Volume 9, Issue 1

2014 CDR summit DVD

C

2014 Vol.9 Iss.1

ollision C The International Compendium for Crash Research

Volume 9 Issue 1

SPRING 2014

Collision: The International Compendium for Crash Research

Validating CDR Data Through Crash Testing

Signs of a Wreck

Volume 9, Issue 1 - Spring 2014

How to Spot a Rolling Disaster and Testing and Simulation

3D Simulation of a Crash Test Series in SIMON Utilizing A, B, C and D Stiffness Coefficients

collisionmagazine.com

Analysis of Motorcycle and Rider Limits on a Curve

An Amazing

Speed Computation

Expert AutoStats®

S I MON

4N6XPRT BioMeknx™

Expert AutoStats® is a computer program containing over 42,000 vehicles cars, vans, utility vehicles, and light pickups. 1945-2012 model years are represented.

This program can be used alone or with our Expert Qwic Calcs® and Expert VIN DeCoder® programs. Also accessible from within REC-TEC.

(Lap top & D esktop W indow s 3 2 & 64 -bit O S C om p atible)

Enter:

M anufacturer and Year

Select:

M odel from pop-up window

Output:

Wheelbase Overall Length Height Wt. Distrib

Curb Weight Width Drive Wheels Front/Rear Track

M id-60's to present output also includes (when available): Front Overhang Rear Overhang Bumper Heights Hood Height Turning circle Wheel radius Bumper-to-Hood Bumper-to-Window

Expert AutoStats® is currently owned by over 700 private individuals and 300 Law Enforcement agencies in the U.S.A., Canada, and South America. Additional information, brochure, and order from can be downloaded from:

www.4n6xprt.com/4n6as.htm

4N6XPRT BioMeknx is designed as a collection of the Biomechanical data of importance to the Accident Investigator into one easily accessible reference location. It is designed as a program to be useful to ALL accident investigators, not just the Biomechanical expert.

The program includes: 1. Over 65 printable illustrations and charts 2. 10 Separate categories or sections of information related to forensic biomechanics 3. Information on walking speeds of people from 17 months to > 65 years 4. Calculation modules for: - segment length from total body height, - segment weights and Centers of M ass (CoM ) based on total body weight, - Predicted M aximum Walking Speed based on total height 5. Information was obtained by review of over 65 scientific texts, several of which are now "out of print"

www.4n6xprt.com/4n6bm.htm

PROGRAM ORDER FORM (Please Print)

SImulation MOdel Non-linear SIMON is a fully 3-dimensional dynamic simulation of the response of one or more vehicles to: • Driver Inputs (steering, braking, throttle, gear shift) • Collisions • Terrain Factors (irregular terrain, curbs, soft soil, slippery regions, hydroplaning, potholes, …)

• Aerodynamics (wind forces, airborne trajectory) SIMON was built using the latest advances in software and simulation technology, based on a new, 3-D vehicle dynamics engine developed by Engineering Dynamics Corporation.

Any number of vehicles may be included in a SIMON simulation. The user assigns initial positions and velocities for each vehicle. The user may also assign driver controls, wheel set-up conditions (tire blow-out, wheel damage, brake adjustment/failure, curb impact) and accelerometers. Using this information, SIMON calculates the forces acting on the vehicle and uses these forces to calculate vehicle position, velocity, acceleration and collision damage at user-specified time intervals. The results may be displayed numerically (in a spreadsheet format) or visually (in 3-D viewers).

SIMON has been validated against numerous well-instrumented vehicle handling studies, including combined steering and braking, severe irregular terrain traversal, rollover tests, staged crash tests and tire blow-out experiments. Program results easily meet Federal standards for the admissibility of scientific evidence.

VISUAL REALITY

Contact Name: ________________________________________________ Company: ____________________________________________________ Street: ______________________________________________________ City:____________________ State:____ Zip:__ __ Country: __________ Phone: (_____) _______________ Fax: (_____) ___________________ E-M ail: ______________________________________________________ Expert AutoStats® 4N6XPRT BioM eknx™ Expert Qwic Calcs® 4N6XPRT Ped & Bike Calcs® 4N6XPRT StifCalcs® Expert VIN DeCoder® (pkg) Expert TireStuf® Order Processing

- $ 625.00 ea.

- $ 495.00 ea.

- $ 275.00 ea.

- $ 375.00 ea.

- $ 650.00 ea.

- $ 550.00 ea.

- $ 85.00 ea.

= ________ = ________ = ________ = ________ = ________ = ________ = ________

- Check = $5.00 / Credit Card = $10.00 / G ovt. P.O . = $15.00 = _______ Notarized Affidavit Requirement $25.00 per required Notarized Signature = _______

Q Deliver via electronic download (Email address Required) Q Ship on USB - $35.00 per disk per program California Sales Tax Enclosed is:

- 8.50%

TOTAL (U.S. Dollars)

= 0.00 = ______

= ________

= ________

Visa ___ MasterCard ___ Am. Ex. ___ Exp ____/____ - Check ___ - Gvt PO ___

Card Number: Name on Card: Signature:

_______________________________________________ _______________________________________________ ________________________________________________

Please M ake Checks*/Purchase Orders Payable to:

4N6XPRT Systems®

8387 University Ave - La M esa, CA 91942-9342 - U.S.A. FAX: (619) 464-2206 Phone: (619) 464-3478 Web: http://www.4n6xprt.com C hecks * M U ST * be draw n on a U.S. bank. O rders are shipp ed within 10 working days of receipt.

Prices subject to cha ng e without notice.

M ultip le orders and Package discounts availab le. Please call for details.

A SOFTWARE SOLUTION FOR EVERY SITUATION:

Total station w/onboard data collection

Robotic total statio n w/Windows CE

Get EVR

□ Reliable □ Compatible See Exhibit A

Evidence Collection Forensic Mapping

Total station or GPS w/data collector

3D Laser Scanner

Evidence Collection Software? w tion n A imacapabilities?

Do we

Yes

No Get Forensic CAD

MapScenes Evidence Recorder • Software for tablets and Windows CE devices • Connect with a total station or GNSS receiver to take measurements and collect evidence • Built for the professional reconstructionist

+ Animation Module

Cloud + Point Module

MapScenes Forensic CAD • A powerful and feature-rich program that provides law enforcement professionals and accident reconstruction specialists with confidence that the evidence they present is precise, compelling, and irrefutable • Produce scaled diagrams for use in cour t, creating a strong visual case for the prosecution or defense. Contains flexible options for point cloud/LiDAR data visualization and anim ation tools • Now with point cloud and animation addon modules • Built specifically for forensic www.MapScenes.com investigators and accident scene reconstructionists 1.800.668.3312

is registered in the U.S. Patent and Trademark Office. All other brand ® MapScenes names, product names or trademarks are property of their respective owners.

Exhibit A

ant

Contents

Spring 2014

Volume 9 Issue 1

inside

10

4

Letter From the Editor

8

NAPARS: Letter From the President

features 10

Three Dimensional Simulation of a Crash Test Series in SIMON Utilizing A, B, C and D Stiffness Coefficients

by Jeffrey Suway, Anthony Cornetto, Ronny Wahba, John Swanson, Fawzi Bayan

222

My Turn At the Wheel: An Amazing Speed Computation

by Erik Carlsson

28

Analysis of Motorcycle and Rider Limits on a Curve

by Nathan A. Rose, Neal Carter, and David Pentecost

38

Signs of a Wreck: How to Spot a Rolling Disaster

by Dan H. Wyatt

75

Signs of a Wreck: Testing and Simulation

by Rusty Haight and Sean Haight

86

Validating Crash Data Retrieval Tool Data through Crash Testing

by James D English

www.collisionpublishing.com

28

86

38

Collision Magazine - Volume 9 Issue 1 3

Letter from the editor Those who follow Collision Magazine closely might have noticed this issue has come out a little later than usual. There are a couple reasons, not the least of which is an effort to tie the feature article by Dan Wyatt about detecting inadequately repaired vehicles with a crash test from this year’s ARC-CSI Crash Conference using a car that was not only inadequately repaired but the flaws in the “repairs” were documented by the author (Wyatt). Being able to tie the two together should, we hope, provide at the very least food-for-thought to our readers who may have encountered vehicles involved in crashes they investigate and analyze which may have been previously crashed and then inadequately repaired.

The next issue will, I’m sure, pick up where we left off sequentially with the previous 8 volumes of Collision; highlighting the content of the CDR User’s content in one issue and the proceedings and tests from the ARC-CSI Crash Conference in the next. This year; however, there is a certain degree of content overlap between the two and, given the anticipated content of the next issue and the necessity of time to compile all the associated data and information, it prompted us to slightly delay this issue in favor of including the related content associated with the inadequate repair article and more complete coverage of other topics in the next issue.

It also gives rise to another topic which has been visited here before and which will be part of the next issue as it relates to the admissibility hearing and “spoofing” EDR data: the ongoing debate over “peer review.” Associated with the admissibility hearing and other companion research which was the basis for the first Special Issue of Collision Magazine (the compendium of Hyundai and Kia EDR data), “peer review” becomes again a point of contention and will be, at least in part, one of the central issues to be found in the next issue.

But what about this issue? As usual, the content of Collision is original material, not regurgitated from a “Bing” search, and covers a range of topics and subjects not found elsewhere. The range of subjects is in keeping with our policy of making as much varied information from a variety of sources available to those capable of independent critical thinking who can read it for themselves and evaluate its usefulness, technical merit and application. That, of course, brings us back to the illusion of “peer review” some would foster as the sole province of a select few...but perhaps that’s a discussion best left for the next issue.

Among the upcoming articles are topics including an evaluation of the effect of wheel slip on reported vehicle speed, Toyota EDR data recording order, information from the mock admissibility hearing from the CDR User’s Summit focusing on the impact of “spoofing” EDR data, and EDR data associated with the Cobalt ignition switch recall; most of which overlap the CDR user’s Summit topics and are the subject of subsequent testing or investigation. In short, the next issue should be pretty amazing.

4 Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

Managing Editor

BACK ISSUES

Collision Publishing Inc PO Box 892885 Temecula, CA 92589 Toll Free: 800-280-7940 Email: editor@collisionpublishing.com Web: www.collisionmagazine.com ISSN: 1934-8681

If you would like purchase back issues of Collision Magazine, please visit www.collisionmagazine.com or call us toll free 800-280-7940.

ADVERTISER INDEX

PAGE

4N6XPRT Systems

Inside Back

COLLISION STAFF

ARAS360

1

Scott Baker Sean Haight Tonya Baker Carla McLeod

ARC-CSI Crash Conference

68-69

CDR User's Summit

19

Collision Magazine Special

7

Collision Safety Institute

26, 83

Crash Data Group (CDR)

6

Engineering Dynamics

Inside Front

FARO

84

Laser Technology Inc

92

MapScenes

2, 49-52

Northwestern University

27

REC-TEC

85

Vericom Computers

37

Visual Statement

20-21, Back Cover

Owner, Managing Editor Senior Editor Advertising Manager Subscription Services

All rights reserved, © 2006-14 Collision Publishing Inc. The opinions and conclusions expressed in this publication and attached data disk and throughout the articles attributed to specific authors are the opinions and conclusions of the authors noted and not necessarily the editorial staff or anyone else for that matter. While some articles have been reviewed for content, the accuracy of reprinted models or equations cannot be fully guaranteed. It is the responsibility of the reader to apply critical thinking to an individual review of the content and make their own personal judgements as to its value to them, individually. At the end of the day, facts belong to everybody, any other opinions to us. The distinction is yours to draw...otherwise, the opinions expressed herein are not necessarily those of any employer, not necessarily ours and probably not necessary. Dis-

senting opinions, discussion or conclusions which may express an adverse position to those expressed herein by specifically cited authors can be addressed in writing by sending an email to the editor at sbaker@collisionpublishing.com or sending a “regular mail” letter to us at PO Box 892885, Temecula, CA 92589. By

sending correspondence to either our email or snail mail addresses listed in this publication you are agreeing that: (1) we are by definition, “the intended recipient” (2) all information in the email is ours to do with as we see fit and make such financial profit, political mileage, or good joke as it lends itself to and, (3) this overrides any disclaimer or statement of confidentiality that may be included on your original message. The entire physical universe, including this publication and attached data disk, may one day collapse back into an infinitesimally small space. Should another universe subsequently re-emerge, the existence of this publication and data disk in that universe cannot be guaranteed.

SUBMIT AN ARTICLE If you would like to submit an article to be published in Collision please email us your article for review or call us toll free 800-280-7940. Email: sbaker@collisionpublishing.com

Included with this issue of Collision

is the 2014 CDR User's Summit data DVD. The DVD includes pdf's of the speaker presentations and any other supporting data compiled in a easy to review, menu-driven data DVD.

ADVERTISING RATES & INFO If you would like to advertise your products or services in Collision Magazine, rates, availability and other information are available online at: www.collisionmagazine.com www.collisionpublishing.com

Next CDR User's Summit January 26-28, 2015 www.cdrsummit.com Collision Magazine - Volume 9 Issue 1 5

Special Edition of Collision

C 2014 SE #1

D OUT MORE

Special Edition #1 - January 2014

TRATION

ec

C ollision

ial

ed

iti

on

The International Compendium for Crash Research

ASH TH US...

ons • Point Cloud

sp

Special Edition #1

Collision: The International Compendium for Crash Research

ON SOFTWARE

released January 2014

JANUARY 2014

HYUNDAI AND KIA CRASH DATA THE INDISPENSABLE COMPENDIUM General Functionality of the Hyundai & Kia EDR Tool(s) A Review of Hyundai & Kia Crash Data from “Real World” Crashes

A Review of Crash Testing Involving Hyundai & Kia Vehicles Coverage Spoofing; Data From Unsupported Hyundai & Kia Vehicles

INCLUDES: “Hyundai & Kia Crash Data A Preliminary Overview” Special edition reprints from Collision Magazine Volume 8

collisionmagazine.com

Order your copy today collisionmagazine.com www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 7

Premier Industry Partner Letter from the President

One of NAPARS goals is to make training opportunities more accessible, as well as to reach out to our members at those training sessions. In addition to the 2014 CDR Summit in Houston in January and the ARC-CSI Crash Conference in Las Vegas in June, NAPARS was present at the Tennessee Highway Patrol Traffic Crash Investigation and Safety Symposium held in Franklin, TN in May. Our next training opportunity will be the 2014 Joint Annual Conference in Portland Maine September 8 – 12th.

It has become virtually a requirement that crash reconstructionists maintain their skill level through regular attendance at quality training sessions. While no one can become an expert in every different specialty area that may be needed in crash reconstruction, training conferences allow you to meet and network with a variety of experts in many different fields. Biomechanical engineers, motorcycle gearheads, EDR experts who know the difference between an SDM Epsilon and a DDEC VI – you will meet them all at crash conferences. And in between sessions they are more than willing to offer advice and wisdom if you just strike up a conversation. They may even become colleagues and friends for life.

The focus of the 2014 Joint Annual Conference is Crush Damage and Energy, which will include an afternoon of live crash testing. Presenters on the main topic will include the legendary Ray McHenry, Principal Investigator on the development of Simulation Model of Automobile Collisions (SMAC) and Calspan Reconstruction of Accident Speeds on the Highway (CRASH)]. Other topics will include How Witness Memories are Formed and Recalled, the Use of Small UAVs for Crash Scene Photogrammetry, Wireless Device Data Forensics, and Digital Forensics of Heavy Vehicle EDRs. Our Thursday night dinner will feature a Casco Bay cruise to Peaks Island where we will enjoy a traditional New England lobster dinner with live music! Special reduced registration rates will be available for active Law Enforcement. Check out all the info at www.crashconference.com.

As always, if you have any questions or suggestions for NAPARS, you can email us at President@NAPARS.org.

Chuck Veppert, President, NAPARS

The National Association of Professional Accident Reconstruction Specialists is a non-profit organization whose members have joined together to share the challenge of dealing with the complex problems of accident reconstruction and to upgrade and ultimately professionalize the accident reconstruction field.

8 Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

www.napars.org

Industry Partners IAARS is one of the oldest associations dedicated to

expanding the knowledge and training of accident reconstructionists. Formed in 1980, we have members from several different countries as well as many different states across the U.S. We have three levels of membership. Our highest level, Fellow, includes a peer review of a reconstruction project. This peer review feature can be very beneficial to a member seeking expert witness qualification in court. One of the criteria a judge can consider when deciding if a person qualifies as an expert is a peer review of his or her work. We offer opportunities for a member to publish work or research in the field of accident reconstruction. This, also, can be very important when qualifying as an expert witness in court proceedings.

Membership in IAARS has other advantages, including a discount (from IAARS) on a subscription to Collision Magazine,

ASPACI is a non-profit society whose members have

joined to share in the challenge of analysing the complicated issues of road collision investigation.

ASPACI was formed in 1991 by a group of police and collision reconstructionists who felt there was a need for information sharing between police and associated institutions in the Australia, South East Asia, New Zealand and South Pacific area.

Its primary function is to assist in the spreading of knowledge and enhancing expertise in the science. The Association seeks to promote a professional approach to collision investigation and to encourage the highest standard of ethics, integrity and honesty among its members.

The ARC Network

was founded in 1998 and since has grown to be the largest and most respected organization for Accident Reconstruction and Traffic Investigation.

The ARC Network is more than just an organization it is a research and communications Internet portal for everything accident reconstruction. The ARC Network provides research tools, Accident Reconstruction Expert directory, event calendar, video database, photoalbum database, article/news database, and a Member's Only area that gives access to various online databases and information.

The ARC Network offers various membership levels to fit your needs and budget. Membership starts at just $89.00 per year.

However, that is where the value of the ARC Network starts.

With your membership you not only get access to everything in the ARC Network, you also receive a, $50 discount to the an-

member discounts at our training seminars and others listed on our web page, www.iaars.org.

We have annual training opportunities at different locations across the country. Our 2013 conference was a joint seminar with SCARS and SeARS and was held in Mt. Pleasant (Charleston), South Carolina. Staged collisions included two pole impacts, some semi-trailer underride crashes, and one offset head-on crash.

Our 2014 conference will also be a joint conference with SCARS and SeARS and will be held from July 20 to July 25, 2014, at the same location. Check our Web site or www.scarsrecon.org for more information.

Sincerely, Fred Rice, President, IAARS www.iaars.com The early days saw the number of members vary with the base of the association in Victoria, Australia. ASPACI became ASPACI Incorporated in 1993 in Victoria. Now we boast members from all over mainland Australia, New Zealand., United Kingdom, and the United States, as well as parts of Asia.

Membership to ASPACI is open to all persons engaged in collision investigation and its allied fields. The association members include Engineers, Police Officers, Independent Consultants, Scientists, Insurance Corporations, Manufacturers and Safety personnel. ASPACI is not a Trade Association or Political Lobby group, nor is it a Police organisation.

nual ARC-CSI Crash Conference, a $50 discount to the CDR User's Summit and a free copy of Greg Russell's Excel Crush Stiffness spreadsheet program. Extend your savings and sign up as a Police Agency member or Platinum member and receive a complimentary subscription to Collision Magazine!

In addition, as a member you have the choice of being listed in the most-visited Accident Reconstruction Directory on the Internet. Our directory gets you exposure and leads.

Scott Baker President The ARC Network (800) 280-7940 www.accidentreconstruction.com expertdirectory.arcnetwork.com arc@accidentreconstruction.com

For information on becoming a Collision Industry Partner send an email - sbaker@collisionpublishing.com www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 9

THREE DIMENSIONAL SIMULATION OF A CRASH TEST SERIES IN SIMON UTILIZING A, B, C, AND D STIFFNESS COEFFICIENTS

A

bstract A method for determining A, B, C, and D stiffness coefficients for simulation in HVE-SIMON using DyMESH has been used to simulate the Yaris crash test series conducted at the 2013 ARC-CSI Crash Conference in Las Vegas. This paper will present a comparison between the real world crash tests and the HVE-SIMON simulations. HVE version 9.1, SIMON version 4.11, and DyMESH version 3.1 were used for the studies presented in this paper.

I

ntroduction A and B stiffness coefficients rely on the basic principle that a vehicles structure absorbs energy and deforms similar to a linear spring. These methodologies rely on a minimum force, energy, or more often, a barrier impact speed required to initiate vehicle crush. Additionally, the results increase in accuracy as the number of crash tests, at varying speeds, increases. Using these standard methods, the crush across the width of the vehicle is used to determine the amount of energy absorbed. This process is a two-dimensional process and does not include the third dimension, crush height.

10 Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

Jeffrey Suway Anthony Cornetto Ronny Wahba John Swanson Fawzi Bayan S-E-A, Ltd. Engineering Dynamics Corporation's (EDC) Human Vehicle Environment (HVE) SImulation MOdel Non-linear (SIMON), using the DyMESH model, allows three-dimensional vehicle meshes and analyses. Based on the methodology that DyMESH uses to calculate collision forces, the height of the crush becomes a factor. Because of this, the stiffness model incorporated in DyMESH is a threedimensional model using A, B, C, and D stiffness coefficients.

Previous work by Cornetto et al. [1] has shown a method for calculating the A, B, C, and D stiffness coefficients for HVE-SIMON, based on the existing crash test data.

In Cornetto et al. the resulting crash pulse and deflectiontime history, as predicted by HVE-SIMON using the derived three dimensional stiffness coefficients, are compared to the data from the NHSTA crash test. Additionally, Suway et al. [2] has shown how the method proposed in Cornetto et al. compares to SIMON with default, 2D stiffness coefficients, as well as EDSMAC4 with default 2D stiffness coefficients.

The authors’ methodology has been applied to a NHTSA crash test of a Toyota Yaris and the resulting stiffness coefficients have been input into HVESIMON. The results of simulations representing the NHTSA crash test and the ARC-CSI crash tests are compared to data recorded during the real world testing as well as post-crash crush measurements. www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 11

M

ethodology The authors have proposed a method for determining the A, B, C, and D stiffness coefficients. This method uses acceleration-time data (crash pulse) from a single vehicle crash test; data that is widely available through the National Highway Traffic Safety Administration (NHTSA). The crash pulse, along with vehicle mass and impact speed are used to calculate the force that is acting on the vehicle and the associated vehicle displacement. An area-displacement function is created from the vehicle mesh. The calculated force (F) divided by the associated area function (A) are plotted versus displacement, creating a F/A versus displacement curve. A third-order polynomial is fit to the F/A versus displacement curve, creating the A, B, C, and D stiffness coefficients. The use of these coefficients can allow for greater accuracy of the vehicle's crash pulse and associated crush in HVE-SIMON using DyMESH. A more detailed explanation and further validation of this method is described in Cornetto et al. [1] and Suway et al. [2].

CG of the vehicle in the HVE simulation to the derived displacement from the NHTSA test (Figure 3).

Figure 1: F/A versus Deflection

Applying this method to calculate the stiffness coefficients, the authors used NHTSA test 5677, a full frontal crash test conducted at 35 mph (56.3 kph) with a 2802 pound (1271 kg) 2007 Toyota Yaris. The x-acceleration recorded from the accelerometer mounted to the left rear floorpan of the Yaris was used to determine the force-time history and the displacement-time history for this crash test.

Since HVE does not have a Toyota Yaris in the existing vehicle database, the authors used a 3D laser scanner to capture the geometry of the undeformed Yaris. The scan data was meshed and imported into HVE. This mesh was used to create the area versus displacement curve; this method is also discussed in Cornetto et al. [1]. The HVE base vehicle used in this paper was a 1995-1999 Dodge Neon, with all relevant parameters altered to match the Yaris data from Expert AutoStats. DyMESH was used with a relaxation rate of 0.05 and the vehicle mesh and barrier mesh were tessellated with 10-inch element size.

Figure 2: NHTSA Crash Test Pulse versus HVESIMON Crash Test Pulse

C

rash Pulse Comparison Results Based on the previously discussed methodology, the authors determined that the A, B, C, and D stiffness coefficients were 25.6, 1.7, 0.044, and -0.0024, respectively. Figure 1 shows the F/A versus displacement curve determined by the author's methodology. Using these stiffness coefficients for the modeled Toyota Yaris, Figure 2 shows a comparison between NHTSA test 5677's crash pulse and the simulated HVE-SIMON crash pulse. For this example, the known impacting velocity from the NHTSA test was used. The authors compared the displacement-time history of the

12 Collision Magazine - Volume 9 Issue 1

FIGURE 3: CG Deflection from the NHTSA Crash Test and the HVE-SIMON Simulation

www.collisionpublishing.com

HVE-SIMON simulations were then completed using the calculated stiffness coefficients to model the full-scale Yaris barrier tests conducted at the 2013 ARC-CSI Crash Conference. There was a Yaris test conducted at 30 mph just prior to the 2013 ARC-CSI Crash Conference, but is part of the same series of testing. Figure 4 shows a comparison between the crash pulse for the 30 mph ARC-CSI Yaris test and the HVE-SIMON simulated 30 mph barrier test. Figure 5 shows the displacement-time histories for the ARC-CSI 30 mph test and the HVE-SIMON 30 mph simulation.

Figure 6 shows a comparison between the crash pulse of the 9.43 mph ARC-CSI test and the HVE simulation at the same impact speed. Additionally, the displacementtime histories for the ARC-CSI 9.43 mph test, determined from the recorded acceleration data and also from video tracking analysis, and the HVE-SIMON 9.43 mph simulation can be seen in Figure 7. Figure 8 shows the comparison between the crash pulse of the 16.36 mph ARC-CSI test and the HVE simulation at the same impact speed.

Figure 9 shows displacement-time histories for the ARCCSI 16.36 mph test, determined from the recorded acceleration data and also from video tracking analysis, and the HVE-SIMON 16.36 mph simulation. Additionally, an HVE-SIMON simulation was created where a Yaris impacted the wall at 9.43 mph, then the vehicle was accelerated to 16.36 mph and impacted the wall again. Figure 10 shows the crash pulse for this case.

Figure 4: ARC-CSI 30 mph Crash Pulse versus HVE-SIMON Crash Pulse at 30 mph

Figure 6: ARC-CSI 9.43 mph Crash Pulse versus HVE-SIMON Crash Pulse at 9.43 mph

FIGURE 5: CG Displacement from the ARC-CSI 30 mph Crash Test and the HVE-SIMON Simulation At the 2013 ARC-CSI Crash Conference, another Yaris was tested at a speed of 9.43 mph. Subsequently, the same Yaris was used in a second test, impacting the barrier at 16.36 mph.

FIGURE 7: CG Displacement from the ARC-CSI 9.43 mph Crash Test and the HVE-SIMON Simulation

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 13

There was one additional Yaris crash test and this test was conducted at approximately 52 mph. Unfortunately, the onboard accelerometers did not capture the crash pulse for this test. Because of this, video analysis is the only tool available to calculate position-time history and then derive a crash pulse. Figure 11 shows the derived crash pulse from the video analysis compared to the HVE crash pulse. Figure 12 shows the calculated CG displacement from the video analysis compared to the CG displacement simulated in HVE.

Figure 8: ARC-CSI 16.36 mph Crash Pulse versus HVE-SIMON Crash Pulse at 16.36 mph

Figure 11: ARC-CSI 52 mph Crash Pulse versus HVE-SIMON Crash Pulse at 52 mph

Figure 9: CG Displacement from the ARC-CSI 16.36 mph Crash Test and the HVE-SIMON Simulation

Figure 12: Displacement from the ARC-CSI 52 mph Crash Test and the HVE-SIMON Simulation

D

amage Comparison Results During the 2013 ARC-CSI Crash Conference, the authors used a three-dimensional laser scanner to capture the Yaris prior to impact and after impact to determine the crush to each vehicle. Figure 13 shows a Yaris prior to any testing.

Figure 10: ARC-CSI 16.36 mph Crash Pulse versus HVE-SIMON Crash Pulse at 16.36 mph, following a 9.43 mph impact 14 Collision Magazine - Volume 9 Issue 1

The average static crush to the bumper bar of the Yaris involved in the 9.43 mph crash and then the 16.36 mph crash was approximately 5.7 inches and the average static crush, including airspace, was approximately 8.7 inches.

www.collisionpublishing.com

For this impact, the HVE-SIMON simulation predicted 9.4 inches of crush. Figure 14 shows a comparison of the HVE-SIMON simulated vehicle crush (top vehicle) to the scan data from the actual ARC-CSI crash tests (bottom vehicle), for the 16.36 mph crash test.

The average static crush to the bumper bar of the Yaris involved in the 30 mph crash was approximately 16.4 inches and the average static crush, including airspace, was approximately 19.4 inches. The HVE-SIMON simulation predicted 19.1 inches of crush, for this impact. Figure 15

Figure 13: Uncrushed Yaris

Figure 14: Scan of the Yaris involved in the 9.43 and 16.36 mph crash www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 15

shows a comparison of the HVE-SIMON simulated vehicle crush (top vehicle) to the scan data from the actual ARC-CSI crash tests (bottom vehicle), for the 30 mph crash test.

The average static crush to the bumper bar of the Yaris involved in the 52 mph crash was approximately 25.8 inches of crush and the average static crush, including airspace, was approximately 28.8 inches. For this crash, the HVESIMON simulation predicted 35.1 inches of crush. Figure 16 shows a comparison of the HVE-SIMON simulated vehicle crush (top vehicle) to the scan data from the actual ARC-CSI crash tests (bottom vehicle), for the 52 mph crash test.

A

nalysis The crash pulse comparisons presented in the figures can be used to subjectively visualize the accuracy of this method; however, to provide an objective representation of the accuracy the Object

Rating Method (ORM) was applied. ORM analysis determines the accuracy at the level of the crash pulse. This method compares the simulation results to the real world tests at a given impact speed in terms of correlation between the following criteria: peak values, peak value occurrence times, and curve shapes. Specifically, the ORM scalar compares the peak values and the ORM shape compares the peak value occurrence times and curve shape. The closer to 100%, the better the correlation [3] [4]. The correlations were calculated for the acceleration time histories for each simulation versus the corresponding real world test.

The author’s did not run the ORM analysis for the 52 mph test case, as the real crash pulse is unknown.

Table 1, 2, 3, 4, and 5 show the results of the ORM analysis for the simulation of the NHTSA test, the 30 mph ARC-CSI test, the 9.43 mph ARC-CSI test, the 16.36 mph ARC-CSI test, and the 16.36 mph ARC-CSI test following the 9.43 mph ARC-CSI test, respectively.

Figure 15: Scan of the Yaris involved in the 30 mph crash 16

Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

ORM scalar ORM shape

SIMON 3D 73% 67%

ORM scalar ORM shape

Table 1: ORM Analysis for the simulation of the NHTSA test

ORM scalar ORM shape

SIMON 3D 80% 67%

ORM scalar ORM shape

Table 4: ORM Analysis for the simulation of the 16.36 mph ARC-CSI Test

ORM scalar ORM shape

Table 2: ORM Analysis for the simulation of the 30 mph ARC-CSI test SIMON 3D 96% 62%

Table 3: ORM Analysis for the simulation of the 9.43 mph ARC-CSI Test

SIMON 3D 89% 46%

SIMON 3D 99% 57%

Table 5: ORM Analysis for the simulation of the 16.36 mph ARC-CSI test following the 9.43 mph test

D

iscussion A good match was obtained between the HVE simulations, with three-dimensional stiffness coefficients, and the corresponding NHTSA crash test. This includes acceleration versus time and crush

Figure 16: Scan of the Yaris involved in the 52 mph crash www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 17

versus time. The level of fit and similarity can be seen in the ORM analysis.

Additionally, a good match was also demonstrated between the HVE simulations, with three-dimensional stiffness coefficients, and the ARC-CSI tests at 9.43 mph and at 30 mph, for both acceleration versus time and crush versus time. Again, the level of fit and similarity can be seen in the ORM analysis.

“

A good match was obtained between the HVE simulations, with three-dimensional stiffness coefficients, and the corresponding NHTSA crash test

"

Although the simulated crash pulse for the 16.36 mph crash test matched the test data well in terms of duration and amplitude, the shape of the crash pulse was not as good as in the 9.43 mph or 30 mph tests. The authors believe that this is because of the fact that the vehicle used for the 16.36 mph test had already been subjected to a 9.43 mph impact. This is noteworthy because, at an impact speed of 9.43 mph, the Yaris is expected to experience some level of permanent deformation to the bumper bar. While the exact amount of deformation was not measured, video analysis of this crash test matched the simulated and derived CG displacement well, confirming the presence of permanent deformation to the bumper bar and crash structure. Additionally, based on video analysis and photogrammetry, it was determined that the front plastic bumper of the Yaris did not significantly deform during the 9.43 mph test. Since there was permanent deformation to the bumper bar of the Yaris prior to the 16.36 mph test, while the front plastic bumper was not appreciably deformed, the point of contact with the front plastic bumper and the barrier would be the same; however, the point 18 Collision Magazine - Volume 9 Issue 1

at which the bumper bar and stiff structure contacted the barrier would change, compared to a vehicle that had not been previously involved in a crash. This would lead to an extended area of airspace and result in important vehicle CG displacement with little to no CG acceleration. Additionally, the pre-deformed Yaris structure would deform differently than an undamaged structure. It is interesting to note that the CG displacement-time history matched well to the crash data. Also, the authors were able to better match the shape of the simulated crash pulse to the measured crash pulse by simulating the 9.43 mph impact prior to the 16.36 mph impact, using the same vehicle (Figure 10). This can also be seen in the ORM analysis, as both the ORM scalar and shape increased in this simulation when compared to the 16.36 mph impact only.

One limitation of this method for calculating three-dimensional stiffness coefficients is that, in fitting a thirddegree polynomial to the F/A versus displacement data for a single impact speed, the curve fit does not accurately predict the F/A versus displacement at displacements substantially greater than those experienced in the crash test used to derive the three-dimensional stiffness coefficients. HVE does allow for a saturation crush value to be input. This creates a zero slope in the F/A versus displacement curve.

This still may lead to a greater amount of simulated crush than would occur in the real world. It should be noted that the authors did not adjust the saturation crush from the default 60 inches used in HVE for any simulation.

This explains the greater CG displacement for the HVESIMON simulation as compared to the CG displacement determined through video analysis in the 52 mph crash test. Based on how modern vehicles are designed and manufactured, the occupant compartment is significantly stiffer than the frame rails, which are designed to absorb energy and deform during an impact. Because of this, F/A should not decrease for any reasonable amount of crush.

At the time of these studies, EDC announced that it will be adding a wheel impact model to HVE-SIMON. This wheel impact model may also improve the correlation for higher speed crash tests.

C

onclusion This paper shows that, using the appropriate three-dimensional stiffness coefficients determined by the author’s method, HVE-SIMON can be used to model vehicle impacts and accurately predict the amplitude, shape, and duration of the crash pulse as well as the vehicle crush. This study showed good correlation between HVE simulations, with three-dimensional stiffness coefficients, and the crash tests performed at lower speeds than the corresponding NHTSA crash test.

At speeds above the NHTSA crash test speed, the accu-

www.collisionpublishing.com

racy decreased with the methodology used in this paper; however, additional studies should be conducted with the addition of the wheel impact model.

R

eferences 1. Cornetto, A., Suway, J., Wahba, R., Bayan, F., “Calculating Three Dimensional Stiffness Coefficients for Use in Three Dimensional Simulation Modeling for Accident Reconstruction” Society of Automotive Engineers Paper (SAE) 2014-01-0473

2. Suway, J., Cornetto, A., Wahba, R., Bayan, F., “Comparison of HVE simulations to NHTSA full-frontal barrier testing: an analysis of 3D and 2D stiffness coefficients in SIMON and EDSMAC4” HVE White Paper – HVEWP-2014-2

3. Hovenga, P. E., Spit, H. H., Uijldert, M., Dalenoort, A. M. 2005 “Improved Prediction of Hybrid-III Injury Values using Advanced Multibody Techniques and Objective Rating” In proceedings of the SAE 2005 World Congress & Exhibition (April, Detroit, MI, USA) Paper No. 05AE222.

4. Eriksson, L., Zellmer, H., “Assessing the BioRID II Repeatability and Reproducibility by Applying the Object Rating Method (ORM) on Rear-End Sled Tests”, Enhanced Safety of Vehicles (ESV) Paper Number 07-0201

rn u T My

l e e h W e h at t

An Amazing Speed Computation By: Erik Carlsson

T

his article is about a 3-vehicle collision that happened in the middle of a February night on a four-lane westbound bridge in New Jersey. There was a light rain at the time, and the bridge was covered with what is often described as black ice. [Of course we all know that black ice is not black. It is completely transparent, and because of this undetectable – except for the fact that at night it reflects brightly the light from tail lamps of vehicles in front.] Water on ice acts like a lubricant, making ice very slippery, and some vehicle drivers on the bridge were unable to control their vehicles. The driver of a minivan, traveling slowly in the far left lane was at the highest point of the bridge when he observed a stopped vehicle some distance ahead in his lane. He applied the brakes, but the vehicle began to slide. It turned around completely and came to rest against the adjacent concrete barrier, facing east, still occupying part of the fourth lane.

(There was no breakdown lane on the left side of the bridge.)

The driver decided to continue his travel, and began his intended U-turn just as a car traveling very slowly in the lane second from the right was abreast.1 When the minivan was halfway through the intended U-turn it was broadsided by a company van traveling in the second lane. The collision was very severe, and the minivan was propelled sideways at such a speed that it not only caught up with the car ahead in that lane, but struck the car with a force high enough to cause its rear window to break. The damage to the car was such that the insurance company subsequently declared it a total loss.

Naturally, there was substantial damage also to the minivan’s left side, though not as extensive as that of the side struck by the company van. The minivan was completely demolished at the two

22 Collision Magazine - Volume 9 Issue 1

impacts, and the rescue crew had to cut off the roof to extract a passenger.

The drivers describe the accident: The driver of the minivan stated at the police investigation that he did not see the company van approaching.2 The driver of the company van stated that the minivan suddenly crossed the travel lanes right in front of him, and that there was nothing he could do to prevent the collision. He did not know how fast he was going, or that the road was icy until he stepped out of his van following the accident (when he slipped and fell.) He had not noticed the warning sign that reads “BRIDGE FREEZES BEFORE ROAD.” The driver of the car stated that he was going no faster than 15 mph due to the slippery road conditions.

Careless driving? There is little doubt that most accident reconstruction analysts would consider the driver of the minivan the culprit, causing the accident by attempting to make a U-turn on an icy bridge right in front of an approaching vehicle.

But what about the other two drivers? Were they merely unfortunate victims of the minivan driver’s attempt to make a U-turn on a slippery highway in the middle of the night? Well, the driver of the car can hardly be accused of having contributed to the accident by driving slowly in the second lane on the four-lane ice-covered bridge. (He was nevertheless named as a defendant in the lawsuit that followed!) Of course, it can be argued that drivers of slow-moving vehicles should al-ways use the lane to the far right, a lane that is often called the “slow lane.” If he had done so, his car would not have been struck by the minivan. But what about the driver of the company van? Was he careless in any way? No, not according to an accident reconstruction firm that analyzed the accident. In their

www.collisionpublishing.com

report, the analysts stated that the driver of the company van was traveling at a speed of 35 mph, and that this was a reasonable speed! Hence the driver of the company van was not careless and did not cause or contribute to the accident.

ergy would be equal to the damage energy of each side of the minivan. But if so, their computation would not show Delta-V, but Equivalent Barrier Speed, which in a case like this are two very different speeds.

Ingenious Speed computations? How did the analysts determine that the speed of the company van was 35 mph when the accident happened?

Well, in their report they stated that when data about the damage to the minivan’s passenger side were entered in the EDCRASH computer program, the computer showed a Delta-V of 25 mph of the company (!) van, and 10 mph when data about the damage to the minivan’s left side was entered. Hence the pre-impact speed of the company van was 35 mph, they stated!

In any case, one can easily see that there is something fundamentally wrong with the speed computation. If indeed the speed of the company van was 35 mph when it broadsided the minivan, and the resulting Delta-V was 25 mph, it would mean that the speed of the company van was reduced to 10 mph during the impact. But this would also mean that during the impact, the broadsided minivan reached a lateral speed of 10 mph. Thus the minivan would have had a Delta-V of 10 mph in the direction of the travel lane, while that of the much heavier company van was 25 mph. This is of course impossible since conservation of linear momentum applies.

How the analysts made the EDCRASH computer program show the Delta-V of the company van based on the damage to the minivan was not explained in the report, nor did they include the creative computations. It may perhaps be reasonable to assume that what the analysts did was to compute the energy dissipated by the deformation of each side of the minivan, and next calculate the speed at which the company van’s kinetic en-

The weight of the company van was 1.6 times that of the minivan. Hence the lateral Delta-V of the minivan had to be 1.6 times the Delta-V of the company van. Thus, if the Delta-V of the latter was 25 mph, that of the minivan had to be 40 mph. But if the company van was moving at 40

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 23

mph following a Delta-V of 25 mph, its speed curred. This damage corresponded to a Delta-v of had to be 65 mph when the vehicles collided.3 10 mph of the company van, the analysts said.

Assuming they meant an equivalent barrier speed It may be argued that due to the elasticity in the of 10 mph, the dissipated energy would be 10 vehicles, especially the impacted side of the mini- squared times the weight of the company van, van, the minivan bounced away from the com- which, as used in the momentum equation above, pany van and therefore began to move away from was 1.6. Thus, the energy required to cause the the company van during the impact, reaching a damage to the minivan’s left side was 160 u, where higher speed. While indeed it is common that an u signifies units of energy.4 impact-ed vehicle moves away from the striking vehicle, especially at low-speed rear end collisions, By the laws of physics, the damage energy dissiby no stretch of the imagination can it be assumed pated in each of two colliding vehicles is inversely that the minivan reached a lateral speed of 40 proportional to their resistance to deformation. In mph at the very instant the speed of the company this case, the resistance to deformation had previously been established for both vehicle models. van had been reduced to 10 mph!

The stiffness coefficient B for the rear end of the Why the inclusion of the driver side damage? actual car model is according to Neptune EngiThe delta-v of 10 mph that according to the anal- neering 61, and that for the sides of the minivan ysis brought the pre-impact speed of the company 53 (lbf/in/in.) When the minivan with its left side van up to 35 mph was based on the damage to struck the car from the rear, the rear bumper of the minivan’s left side. This side was damaged the car came to intrude into the side of the miniwhen the minivan struck the rear end of the car van, causing an impression having a length equal an instant after the first collision. The reason the to the bumper's length. We can therefore consider analysts included the minivan’s left side damage the length of the damaged areas on both vehicles in their computation of the speed of the company to be equal.5 Their resistance to deformation will van is of course that the energy dissipated by that therefore in the computations be directly propordamage had its origin in the company van’s ki- tional to their stiffness coefficient B. With this in netic energy. This is true, but this also applies to mind, the dam-age energy of the car calculates to the damage to the car. This damage, as said earlier, 160*53/61, which rounded down to the nearest was such that the car was considered a total loss. 10’s is 130 u. Thus the combined energy dissiBut in addition, the car’s speed increased when pated by the two vehicles at the second collision the car was hit from behind by the minivan. Thus was 290 u.6 the car’s kinetic energy increased at the impact.

This energy also had to have its origin in the com- The weight of the car was very similar to that of the minivan, so in our computation we can call the pany van’s pre-impact kinetic energy. weight of each one for just 1, or even 1.0, (implyFurthermore, the company van, which had a ing a somewhat higher accuracy in the computamodified front bumper, sustained so much front- tions. (The weights of the two vehicles were 3100 end damage that the estimated repair cost exceed- and 3050 pounds respectively, for a weight ratio ed $7,000 (back in 2001.) It can therefore be con- of 1.02.) Using the speed stated by the car driver, cluded that also the damage energy of the front 15 mph, and a combined energy loss of 290 u at end of the company van was significant enough the collision between the minivan and the car, the to have played a role in speed computations based pre-impact speed of the minivan is found through on dissipated energy. the following simple second-degree equation: What was the speed of the company van, really?

Naturally, the true impact speed of the company van had to be substantially higher than 35 mph, but how much? A good starting point to solve this problem is to consider the second collision, which is when the damage to the minivan’s left side oc24 Collision Magazine - Volume 9 Issue 1

vmv + 15 = 2 vcar, and vmv2 + 152 = 2 vcar2 + 290, where vmv is the pre-impact speed of the minivan and vcar is the post-impact speed the car, which is also the speed of the minivan when it at the end of the impact moved at the same speed as the car.

www.collisionpublishing.com

The equation shows the pre-impact speed of the minivan to be 39 mph, which translates to a deltav of 12 mph for both the car and minivan. (All calculated speeds rounded to the nearest integer.)

Note that the company van is not a factor in the above equation!

car, who to his amusement stated that he saw the driver of the minivan looking behind him just as he started, as if looking out for eastbound traffic on the westbound one-way bridge.

He probably turned his head to the left and kept looking steadily through only his side window However, if we instead of disregarding the com- once he began his left turn, as many drivers do pany van at the second collision consider it being when making a sharp left turn. in direct contact with the minivan, still pushing 3 As shown in COLLISION - FALL 2012 issue: it forward, the computation shows a speed of 35 ”How To Use The Combined Speed Formula, Or mph when the minivan reached the car, and a post-impact speed of the three-vehicle combina- Not,” momen-tum equations can with great adtion of 29 mph. This means a delta-V of 14 mph vantage be simplified as done above, and is also the method that has been used by ACCIDENT of the car, and 6 mph of the two vans.

RECONSTRUCTION JOURNAL in “Test Your For a post-impact speed of 35 mph of the two vans Skill” since 1991. resulting from the first collision, the pre-impact 4 The simplified method used in the momentum speed of the company van calculates to 35*2.6/1.6, which is 57 mph. The corresponding delta-V is 21 equations applies equally well to energy computamph. If the higher post-impact speed, 39 mph, at tions, as was also shown in the Fall 2012 issue of the second collision is used, the equivalent speed COLLISION. of the company van calculates to 63 mph, with a 5 Actually, the length of the damaged area of the delta-v of 24 mph. side of the minivan must have exceeded the length WHAT IF? An issue that was not addressed in the of the car’s rear bumper to some extent. Discountanalysts' report is what would have happened if the ing this additional length of the crush zone of the driver of the minivan had paid attention to the ap- minivan will result in an understatement of the proaching company van and waited with his in- damage energy of the car, and consequently also tended U-turn until the company van had passed. the computed speed of the company van.

In such a case there would of course not have been a sudden reduction of the speed of the company van at the point where it now struck the minivan.

The company van would instead have continued at un-changed speed and struck the car, which at that very moment was only a short distance ahead.

Any suggestion that the driver of the company van might in such a case have avoided rear-ending the car by rapidly changing lane when he observed the car is unreal. It is impossible to make a rapid lane change on a very slippery road.

2

Coefficient A, which is normally used in combination with coefficient B, is not a parameter that has any effect on the collision force and dissipated energy during collisions. It is used in post-crash computation to compensate for the difference between the actual damage during the collision and the somewhat less damage that can be measured after the collision, and which, if not compensated for, would result in an understatement of the dissipated energy and collision force. Note that in the computation above I have presumed that the Any reader of this article who has some questions stated damage energy of the minivan was based on about the veracity of my speed computations is very both coefficients so as to show the actual energy welcome to contact me with his or her thoughts. dissipated at the moment of maximum deformation of the vehicles.

My email address is erikcarlsson@live.com.

6

Footnotes: That so was the case was at the subsequent police investigation confirmed by the driver of that

1

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 25

The Collision Safety Institute is the longest standing provider of

Crash Data Retrieval Tool Training In the world.

Visit our online calendar for a current listing of CDR Courses or contact us to if you would like to host a CDR training course.

CSI has offered unparalleled training and support on the Bosch CDR Tool.since 2000. Current content of the CDR Data Analyst course includes a review of concepts and applications common to all supported auto manufacturers, as well as speciics on the data available from the most current modules found in passenger cars, light trucks, and SUVs.

Collision Safety Institute || http://www.collisionsafety.net || (858) 484 9794

Analysis of Motorcycle and Rider Limits on a Curve Nathan A. Rose, Neal Carter, and David Pentecost Kineticorp, LLC

F

rom 1975 to 1980, H.H. Hurt investigated 4,500 motorcycle accidents – 900 with onscene, in-depth investigations and 3,600 using police reports – to identify common factors that contributed to causing these accidents [1]. The accidents in Hurt’s dataset occurred in the Los Angeles, California area. He found that “the most common motorcycle accident involve[d] another vehicle causing the collision by violating the right-of-way of the motorcycle at an intersection, usually by turning left in front of the oncoming motorcycle because the car driver did not see the motorcycle.” In these intersection collisions, the motorcycle rider was “usually inconspicuous in traffic, inexperienced, untrained, unlicensed, unprotected and uninsured and [did] a poor job of avoiding the collision.”

In addition to these intersection collisions, “approximately one-fourth of [the] motorcycle accidents were single vehicle accidents involving the motorcycle colliding with the roadway or some fixed object in the environment.” Hurt further found that “in the single vehicle accidents, motorcycle rider error was present as the accident precipitating factor in about twothirds of the cases, with the typical error being a slide-out and fall due to overbraking or running wide on a curve due to excess speed or undercornering…” In an earlier article, Hurt had also reported that “environmental problems such as animals in the roadway, oil, water, and gravel contamination of the roadway, grooved freeways, [and] railroad tracks” can contribute to motorcycle accidents [2].

28 Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

Hurt’s findings provide a statistical picture of the factors that can contribute to the occurrence of motorcycle accidents. However, reconstructionists are sometimes asked to determine which of these factors played a role in a particular accident. For example, suppose that a motorcyclist loses control and falls down while traveling through a curve that contains an area of deteriorated roadway.

For this type of accident, questions may arise regarding the role that the deteriorated roadway played in causing the accident. In these cases, the mere presence of deteriorated roadway in the area of the accident does not establish that this deterioration played a direct role in the accident. Other possible factors – such as speed – should be considered, as should the specific characteristics of the deterioration and the effect it would likely have on the motorcycle. In such a case, the motorcycle rider may have lost control because they entered the curve at too high of a speed and this speed led to what Hurt referred to as “overbraking” or “undercornering”. Acci-

dent statistics can certainly provide a useful list of possible factors and worthwhile lines of inquiry in such a situation. However, these statistics cannot enable a determination of which possible factors contributed in a specific instance. Identification of the factors contributing to a particular accident must ultimately rely on the physical evidence from that accident and on the physics that elucidates the meaning of that evidence.

This article focuses on single-vehicle motorcycle accidents that occur on curves and explores the physics that would enable a reconstructionist to determine the role the rider’s actions played in the accident. Specifically, the circumstances that might lead to the following two types of rider error are analyzed: (1) “a slide-out and fall due to overbraking” and (2) “running wide on a curve due to excess speed or undercornering.” These rider errors typically lead to the motorcycle falling down and sliding on the ground or to the motorcycle impacting a roadside object.

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 29

The discussion here explores the circumstances that can lead to these errors and identifies what analysis would show they were present during a particular accident. Other articles have adequately addressed specific methodologies and data for calculating the speed of a motorcycle following an accident. Fricke provides a basic overview of motorcycle reconstruction [3]. Bartlett provides a helpful review and analysis of the available sliding motorcycle deceleration rate data [4]. Many others could be cited. The purpose of this article is not to reopen the discussion of the work performed by these authors. Instead, this article extends the work of these authors by discussing techniques for interpreting the significance of a calculated speed. Was the motorcyclist traveling too fast for the curve or not? What does it mean to travel too fast around a curve? Did the motorcyclist’s speed create a situation that led to overbraking or undercornering? These are the questions addressed here.

“

carriage component contacts the road and by the rider's psychological limits..

M

otorcycle Lean on a Flat Curve Once the initial speed of the motorcycle has been calculated, an important consideration becomes the lean angle that would have been necessary for the rider to traverse their chosen curved path at that speed. The lean angle required for a particular path will be the angle that brings the overturning moment generated by the tire frictional forces into balance with the opposing moment generated by the tire forces perpendicular to the road surface. The required lean angle increases with increasing speed and decreasing path radius. Fricke [3] and Cossalter [5] report that the lean angle of a motorcycle for a particular path and speed can be calculated with the following equation:

(1)

Three factors limit the speed of a motorcycle on a curve – the limit of the available friction, a geometric limit that is defined by the lean angle at which a motorcycle undercarriage component contacts the road and by the rider's psychological limits.

"

Three factors limit the speed of a motorcycle on a curve – the limit of the available friction, a geometric limit that is defined by the lean angle at which a motorcycle under30 Collision Magazine - Volume 9 Issue 1

In this equation, θ is the lean angle of the motorcycle relative to the road surface, vmc is the velocity of the motorcycle, g is the gravitational acceleration, and r is the path radius. This equation assumes that the motorcycle is cornering on a roadway without cross- slope. It also assumes that the motorcycle is traveling a steady speed, that the rider is leaning at the same angle as the motorcycle, and that the part of the tire contacting the road does not change as the motorcycle leans.

Three factors limit the speed at which a motorcycle can traverse a given curve. The first of these is the limit of the available friction between the motorcycle tires and the roadway. The second is a geometric limit that is defined by the lean angle at which the motorcycle’s foot peg – or some other component – comes into contact with the roadway.

The third is the limit imposed by the rider’s psychological limits – their willingness to approach either the geometric or friction limits of their motorcycle. Roadway superelevation decreases both the necessary friction force and the angle a motorcyclist will need to lean in order to traverse a particular curve. Thus, in determining the limits of a motorcycle or rider on a particular curve, the superelevation of that curve can be an important factor to consider. The next section discusses how the roadway superelevation can be incorporated into Equation (1).

I

ncorporating Superelevation To begin, consider Figure 1, which is a diagram of a motorcyclist traversing a leftward curve with a superelevation. As this diagram shows, the superelevation angle has been given the symbol φ and, as in Equation

www.collisionpublishing.com

(1), θ designates the lean angle of the motorcycle relative to the road surface. Thus, the lean angle of the motorcycle and rider relative to the vertical direction is φ + θ. In this derivation, counterclockwise rotations are positive, and therefore, the superelevation and lean angles for a leftward curve are positive. Figure 1 also depicts the forces applied to the cornering motorcycle – the combined weight of the motorcycle and rider applied at their effective center of mass (W), the lateral friction force (Ffriction) applied at the tire contact patch, and the normal force (Fnormal) applied at the tire contact patch.

In order to remain in equilibrium as it traverses the curve, the resultant of the normal and friction forces must act along the line connecting the tire contact patch to the center of mass of the motorcycle and rider. For this to be the case, the friction and normal forces must be related to the lean angle as defined by the following equation:

(3) By examination of Figure 1, it can be seen that (4) Further, for a motorcycle traversing a curved path (5) Therefore, Equation (3) can be rewritten as follows: (6)

(2) Substituting Equation (2) into Equation (6) yields: (7)

As it traverses the curve, the motorcycle depicted in Figure 1 is in static equilibrium in the vertical direction. Therefore, the sum of the forces in the vertical direction is equal to zero. This can be written as follows: (8) Substituting Equation (2) into Equation (8) and solving for Fnormal yields: (9) Substituting Equation (9) into (7) yields the following equation: (10)

Figure 1: Forces Applied to a Cornering Motorcycle Newton’s second law dictates that, for the scenario depicted in Figure 1, the sum of the forces in the lateral direction are equal to the mass multiplied by the lateral acceleration.

Roadway superelevation will not typically exceed 6 or 7 degrees [6]. Given this, we can employ small-angle assumptions to simplify Equation (10). Specifically:

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 31

(11) (12) Substituting Equations (11) and (12) into (10) yields the following equation: (13) Using trigonometric identities, it can be show that (14)

Figure 3: Lean Angles for 500 foot Radius Curve with Various Superelevations

Therefore: (15) Equation (15) shows that the superelevation angle reduces the required lean angle relative to the road surface and that each degree of superelevation reduces the required lean angle by one degree. The graphs of Figures 2 and 3 plot the lean angle for various speeds and superelevation angles.

Figure 2 is for a curve radius of 250 feet and Figure 3 is for a curve radius of 500 feet. For both graphs, speed in miles per hour is plotted on the horizontal axis and lean angle in degrees is plotted on the vertical axis. From these graphs, the following relationships can be observed: (1) As a motorcyclist’s speed around a curve increases, their lean angle must also increase; (2) Superelevation in a curve reduces the magnitude of lean necessary for a motorcyclist to traverse a particular curve at a particular speed; (3) The larger the radius of a curve, the less lean angle required for a motorcyclist to traverse that curve.

Figure 2: Lean Angles for 250 foot Radius Curve with Various Superelevations 32

Collision Magazine - Volume 9 Issue 1

A

ssumptions Equation (15) was developed with several assumptions that reconstructionists using it should keep in mind. First, this equation assumes the motorcycle is traveling a steady speed. Second, this equation assumes that the motorcycle and its rider have the same lean angle.

This will often be an accurate assumption, but clearly a rider has the option of leaning either more or less than they lean the motorcycle and reconstructionists should be attentive to situations where it might not apply. As Cossalter has noted [5]:

The motorcycle roll angle on a turn is influenced, in a significant way, by the rider’s driving style. By leaning with respect to the vehicle, the rider changes the position of his center of gravity with respect to the motorcycle… if the rider remains immobile with respect to the chassis, the center of gravity of the motorcycle-rider system remains in the motorcycle plane…if the rider leans towards the exterior of the turn, the center of gravity is also moved to the exterior of the turn with respect to the motorcycle. As a result, he needs to incline the motorcycle further so that the tires, being more inclined than necessary, operate under less favorable conditions…If the rider leans his torso towards the interior of the turn and at the same time rotates his leg so as to nearly touch the ground with his knee, he manages to reduce the roll angle of the motorcycle plane. When racing, the riders move their entire bodies to the interior of the turn, both to reduce the roll angle of the motorcycle and to better control the vehicle on the turn.

Finally, Equation (15) assumes that the tire has no width, such that the part of the tire contacting the roadway does not change as the motorcycle leans. In reality, as the mo-

www.collisionpublishing.com

torcycle leans, the portion of the tire contacting the road changes and the contact patch moves in the direction of the lean (Figure 4). This results in the effective lean angle of the motorcycle being slightly less than the actual lean angle. Thus, the actual lean angle required for a particular curved path will be slightly higher than that predicted by Equation (15). Further research and testing could explore the magnitude of this effect.

(16) To develop a comparable equation for a curve with superelevation, the lateral forces depicted in Figure 1 can again be equated to the lateral inertial force, as written in Equation (6). When the motorcycle reaches its friction limits: (17) Substituting Equation (17) into (6) yields the following equation.

(18) Returning now to the sum of forces in the vertical direction, Equation (8), and substituting Equation (17) into this equation yields: (19) Substituting Equation (19) into (18) yields the following equation: (20) Again employing small angle assumptions and solving for the maximum, friction limited speed in Equation (20) results in the following equation:

(21)

Figure 4 : Change in Contact Patch Location with Tire Lean

F

riction Limited Speed The first factor that limits the speed at which a motorcycle can traverse a given curve is the limit on the available friction between the motorcycle tires and the roadway. On a curve with no superelevation, this limit will be reached when the lateral acceleration (in gravitational units) of the motorcycle/rider combination is equal to the coefficient of friction between the roadway and the motorcycle tires. Equation (16) expresses this limit.

Lambourn examined friction coefficients between motorcycle tires and dry asphalt roadways and found peak friction coefficients of 1.2 [7]. With this level of friction, a motorcycle traversing a flat, 250-foot radius curve would have a friction limited speed of 67 mph. On a flat, 500foot radius curve, the same motorcycle would have a friction limited speed of 95 mph. If superelevation is present, these speeds would increase. As the next section will discuss, not all motorcycles will have the geometric clearances necessary for the lean angle that these speeds would require. Thus, a motorcycle’s physical limits will normally be determined by its maximum lean angle, not by the friction limits of its tires [8].

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 33

G

eometric Limit on Speed The second factor that limits the speed of a motorcycle around a curve is the geometric limit that is defined by the lean angle at which motorcycle components other than the tires – a foot peg, for instance – will come into contact with the roadway. This limit is defined by the geometry of each particular motorcycle, but will generally be in the range of 25 to 50 degrees [9]. On a flat, 250-foot curve, a motorcycle that can lean 25 degrees will be able to achieve a speed of 42 mph before components begin to contact the roadway. A motorcycle that can lean 50 degrees would be able to achieve the friction-limited speed of 67 mph. Clearly for most motorcycles, the geometric limit will be more limiting than the friction limit.

It is worth mentioning that suspension loading and compression will have a small effect on the geometric limit for a motorcycle on a curve. As the load on the suspension increases, the springs will compress more and the ground clearance of components on the motorcycle will decrease.

To account for this in evaluating the geometry-limited speed of a motorcycle around a curve, an equation can be developed to calculate the suspension load for a rider operating a motorcycle through a particular curve at a given speed. Developing this equation begins by parsing the weight of the motorcycle/rider combination into individual components as follows: (22) In this equation, the weight of the motorcycle has been divided into sprung and unsprung components. The sprung weight of the motorcycle is the portion of the motorcycle weight that is supported by the suspension and the unsprung weight is the weight of the motorcycle components that support the suspension. The unsprung portion of the motorcycle weight will not contribute to compressing the suspension springs. Thus, when the motorcycle is upright, the force compressing the suspension is a follows: (23) The force compressing the suspension will increase during cornering. To quantify this increase, the lateral component of the force on the suspension can be equated to the inertial force of the rider and sprung weight of the motorcycle, as follows:

Substitution in Equation (15) and solving for Fsuspension yields the following equation:

(25)

Equation (25) demonstrates that the force on a motorcycle’s suspension depends on the superelevation of the roadway and the motorcycle lean angle. Since the lean angle depends on the motorcycle speed and the radius of the curve being traversed, so does the force on the suspension, and thus, the compression of the suspension.

This means that the maximum lean angle of a particular motorcycle will depend, to some degree, on the speed and curve radius.

To explore the significance of these suspension effects, we physically tested the suspension on a 2003 Harley Davidson FXD motorcycle and documented the motorcycle’s ground clearance under various loading conditions. For each loading configuration, a Faro Laser Scanner Focus3D was used to document the position of the motorcycle undercarriage relative to the test platform and to measure the ground clearance. With the fuel tank approximately five eighths full, this motorcycle weighed 671 pounds. Without a rider, the motorcycle had 5.34 inches of ground clearance, as measured at the kickstand stop. The following four additional configurations were tested: (1) the motorcycle with a 201 pound rider; (2) the motorcycle with a 201 pound rider and 51 pounds of ballast; (3) the motorcycle with a 201 pound rider and 105 pounds of ballast; (4) the motorcycle with a 201 pound rider and 155 pounds of ballast. Figures 5 and 6 are two photographs of this exemplar motorcycle, with and without the rider. Table 1 lists the ground clearance for the motorcycle undercarriage for the various loading conditions. With the ground clearance that resulted from loading the suspension of this motorcycle with a rider, this motorcycle would have a maximum lean angle of 33 degrees. With the ground clearance that resulted from loading the suspension of this motorcycle with a rider and 155 pounds of ballast, this motorcycle would have a maximum lean angle of 32 degrees. These values show that the suspension load has an effect on the maximum lean angle, but in most instances, this effect is unlikely to be significant.

(24)

34

Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

Given the small effect of the suspension compression, the maximum lean angle for a motorcycle can often be reasonably estimated from what is reported in manufacturer specifications. The maximum lean angle reported in these specifications will typically have been determined according to the procedure described in Society of Automotive Engineers (SAE) Recommended Practice J1168 [10]. This recommended practice specifies that the front and rear suspension systems on the motorcycle be compressed to 75% of their maximum travel. The motorcycle is then leaned until a component contacts the test surface and the lean angle is measured.

Figure 5: 2003 Harley Davidson FXD

Figure 6: 2003 Harley Davidson FXD with Rider

W

illingness to Lean The amount of lean required by a rider as they traverse a curve will be determined by their speed in the curve. Many riders will reach a psychological limit on their willingness to continue to lean their motorcycle before they reach the maximum lean angle of their motorcycle [9]. Watanabe & Yoshida found that the maximum lean angles utilized by novice riders were typically in the range of 15 to 25 degrees and those used by experienced riders were in the range of 34 to 40 degrees [11]. These results imply that the experienced riders in the study by Watanabe & Yoshida used maximum lean angles that would approach the lean angle limits of many motorcycles, whereas novice riders stopped well short of the motorcycle limits. Using the middle values of these ranges, these results further imply that on a flat, 250-foot curve, an experienced rider would be willing to lean far enough to traverse the curve at a speed of 53 mph whereas a novice rider would only be willing to lean far enough to traverse the curve at a speed of 37 mph.

Thus, particularly for inexperienced riders, it would be possible for speed to contribute to causing a motorcycle accident in a curve even if the motorcyclist’s speed has not reached either the friction-limited or geometric limited speeds. If a motorcyclist enters a curve at a speed that requires them to lean beyond the angle they are willing to achieve, then the motorcycle will tend to drift toward the outside of the curve and the rider may take action in response to the situation that leads to a crash.

D

iscussion and Conclusions This article has identified the following three limits on the speed at which a motorcyclist can traverse a curved path: (1) the friction limit; (2) the geometry limit; and (3) the rider’s willingness limit. These limits are expressed by the following equations.

Table 1: Harley Davidson FXD Ground Clearance Under Various Loading Conditions

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 35

Friction-Limited Speed (21) Geometry or Willingness Limited Speed (26) Equation (26) is equivalent to Equation (15), with the exception that the maximum lean angle is utilized. This could be the maximum lean angle of the motorcycle or the maximum lean angle the rider is willing to achieve.

“

The rider’s response to reaching one of these three limits can determine if they successfully traverse the curve

2. Hurt, H.H., “Human Factors in Motorcycle Accidents,” Paper Number 770103, Society of Automotive Engineers, 1977.

3. Fricke, Lynn B., Traffic Crash Reconstruction, Second Edition, Northwestern University Center for Public Safety, 2010.

4. Bartlett, Wade, et al, “Motorcycle Slide-to-Stop Tests: IPTM data through 2006,” Accident Investigation Quarterly, Spring 2007.

5. Cossalter, Vittore, Motorcycle Dynamics, Second Edition, 2006.

6. A Policy on Geometric Design of Highways and Streets, 1990 Edition, American Association of State Highway and Transportation Officials.

"

The rider’s response to reaching one of these three limits can determine if they successfully traverse the curve. When a motorcyclist is operating at one of these limits around a curve and crashes, it would be reasonable to conclude that the rider was operating their motorcycle at too high a speed for the curve, or at least, too fast given their ability level.

When a motorcycle rider drives too fast into a curve, at least two possible accident scenarios exist. One possibility is that they will brake to slow down. If they utilize their rear brake, the combined demands of braking and cornering can result in this tire losing traction. The rear of the motorcycle can slide out and fall down. Another possibility is that the motorcyclist will simply not lean the required amount for the speed and curve radius they are traversing.

This will result in the motorcycle traversing a larger radius curve that what the rider intended or what is required by the roadway geometry. This, in turn, can lead to the motorcycle exiting the outside of the curve and striking an object on the outside of the curve, such as a guardrail.

36 Collision Magazine - Volume 9 Issue 1

R

eferences 1. Hurt, H.H., “Motorcycle Accident Cause Factors and Identification of Countermeasures, Volume I: Technical Report,” Prepared for the U.S. Department of Transportation, January 1981.

7. Lambourn, Richard F., Anna Wesley, “Motorcycle Tire/Roadway Friction,” Paper Number 2010-010054, Society of Automotive Engineers, 2010.

8. Bartlett, Wade, “Time and Distance Required for a Motorcycle to Turn Away from an Obstacle,” Paper Number 2014-01-0478, Society of Automotive Engineers, 2014.

9. Bartlett, Wade, “Lean Angle Selection by Motorcycle Riders,” Accident Reconstruction Journal, Volume 21, No. 2, March/April, 2011.

10. “Motorcycle Bank Angle Measurement Procedure,” SAE Surface Vehicle Recommended Practice, J1168, March 2012.

11. Watanabe & Yoshida, “Motorcycle Handling and Performance for Obstacle Avoidance,” International Congress on Auto Safety, 1973.

A

cknowledgements We would like to acknowledge and thank Steven Beier of Kineticorp for producing several of the graphics used in this article. We also thank William Neale, David Danaher, and Dorothy Kelly of Kineticorp for their helpful comments on draft versions of this article.

www.collisionpublishing.com

SIGNS OF A WRECK How to spot a Rolling Disaster Dan H. Wyatt

Collision Service Investigators of North Carolina, LLC.

Editors Note

How often has a crash been investigated where the assumption was made that the involved vehicle(s) were in “essentially good as new” condition but, unknown to the investigator, one or more of the involved vehicles had been subjected to a prior repair which wasn’t necessarily up to par or which didn’t leave the involved vehicle in anything close to the same shape it was in when it was new? Dan Wyatt of Collision Service Investigators of North Carolina has over 25 years of auto body repair experience and has been licensed as a Motor Vehicle Damage Appraiser by the North Carolina Department of Insurance since 2003. He has obtained more than 17 training certificates from the Inter-Industry Conference Auto on Collision Repair (I-CAR), which was formed by the collision industry in 1979. This authorized reprint of part of his book “Signs of a Wreck” together with the discussion of a crash test involving one of the vehicles Mr Wyatt evaluated is offered as, at least, “food for thought” for the next time a vehicle involved in a crash you’re working doesn’t seem to have performed “quite as anticipated.” His work here includes some basics of auto body repair and offers some valuable insight on what to look for toward trying to identify inadequate repairs which might affect vehicle performance in a crash in a straight-forward, easy-to-read first person approach. The complete book is available from Mr Wyatt at 704-216-0081; www.csiofnc.com or email: dwyatt@csiofnc.com 38 Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

I

ntroduction The original book “Signs of a Wreck” was designed to provide general information and insight for consumers as well as used auto dealers in an effort to help them avoid unknowingly purchasing a damaged and inadequately repaired vehicle. At least some of the material is applicable to the crash investigator or reconstructionist who may want to evaluate whether or not one or more of the vehicle(s) involved in a crash may have been previously repaired and that repair’s effectiveness may play a role in the performance of that vehicle during the subsequent crash.

The original book includes suggestions for the potential used car buyer with respect to the condition of a vehicle including what to look for when buying a used car and sources of information with respect to that vehicle’s history. This excerpt of “Signs of a Wreck” is focused on those portions of the original book which relate to the techniques best suited to the crash investigator rather than the consumer.

V

ehicle Exterior Inspection Assuming the reader is involved in investigating a crash where one or more of the involved vehicles may have been involved in a previous crash and repaired to one degree or another, the logical place to start would seem to be to conduct a visual inspection of the vehicle in an effort to determine if it might have been previously repaired. The effectiveness of the repairs would come later.

One way to identify previous repair(s) made to a vehicle is to spot color variance or mismatched paint. At some point in time, we have all looked at a vehicle and wondered if there was a mismatch in the paint—a color variance. Depending on the amount of sunlight and the angle you are viewing the car from, a color variance in the paint may be obvious or may not show up at all.

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 39

Figures 1 and 2 are of a gray 2007 Honda Odyssey which show, in the author’s opinion, noticeable color variance.

The author was fortunate to be able to photograph the van both on a cloudy day and on a sunny day to show how lighting may change the way we see a color variance. On both days, the color variance was noticeable. The color variance in the paint is at the top edge of the fender to the A-pillar (Figure 3). The painter “blended” the front doors, but he did not blend the paint onto the A-pillars. Blending means to paint onto the next adjacent body panel so that a color match occurs. The painter DID NOT blend the paint onto the A-pillar, so a mismatch of paint or color variance is particularly noticeable.

Figure 1: 2007 Honda Odyssey

Figure 2: 2007 Honda Odyssey showing color variance Similarly, the rear bumper color doesn’t match the rear quarter panels which could be an indication of a simple repair or the replacement of the whole rear end of the vehicle (Figure 4). One should keep in mind that vehicle manufacturers may even have some color variance in their bumper covers when they are matching paint to the front fenders or to the rear quarter panels. Many vehicle manufacturers have companies supply them with pre-painted bumper covers and a color variance may occur that way.

One should be careful to not jump to the conclusion that the vehicle has been damaged just because the bumper covers are not the exact color of the original paint.

Another characteristic of repair would be paint finish defects. These can range from the obvious (for example a paint run or sag) or to the more subtle (such as an “orange 40

Collision Magazine - Volume 9 Issue 1

Figure 3: 2007 Honda Odyssey showing The color variance in the paint is at the top edge of the fender to the A-pillar

www.collisionpublishing.com

Figure 4: Indication of a simple repair or the replacement of the whole rear end of the vehicle peel” appearance which can be a common effect seen on many new vehicles, so one should not assume that a vehicle has been damaged simply because of the presence of orange peel.

scratches in the paint finish as seen in Figure 5. Vehicle inspections can be very effective when done under very adequate florescent lighting particularly when one is looking for paint defects.

Sunlight can hide other defects in the paint such as dirt, fisheyes, orange peel, pinholes, runs or sags, as well as sand

Paint flaking or cracking occurs is often most visible on a replaced bumper cover. When you see this, it means the

Figure 5: efects in the paint such as dirt, fisheyes, orange peel, pinholes, runs or sags, as well as sand scratches in the paint finish www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 41

replacement bumper cover was not properly prepared for refinishing or painting. A simple thing like a stone hitting the bumper cover can cause the clear coat to begin to flake or crack off from the bumper cover. Look closely at the pictures in Figure 6 and one can see the clear coat flaking off the edge of this bumper cover.

Figure 6: Clear coat flaking off the edge of this bumper cover

Figure 7: Overspray that occurred when the painter did not properly “mask” the vehicle

One should also look for paint tapelines and paint overspray on parts that should not have paint on them. The photos in Figure 7 are of overspray that occurred when the painter did not properly “mask” the vehicle. Tapelines are a buildup of paint against the masking tape during the spraying process. Tapelines can be obvious even to the untrained eye. One might find tapelines inside the fender edges under the hood, doorjambs (see Figure 8) or the quarter panels and trunk lid openings and may be found in other places and along other edges of surfaces of the vehicle. A good painter will take extreme pains not to have tapelines and overspray.

or plate, one may also find Federal Anti-Theft Standard (FATS) Labels in various places around a vehicle.

While the author assumes that skilled crash investigators sufficiently trained to look for a vehicle’s VIN plate and identify whether or not it is the original plate or sticker or may have been replaced, it is worth mentioning that, in addition to the “normal” locations of a VIN sticker 42

Collision Magazine - Volume 9 Issue 1

On should look for the “FATS” labels although not all vehicle manufacturers place FATS labels on their vehicles, so one should not jump to the conclusion that if there is no FATS label, the part has been replaced. For the vehicles that do have FATS labels, the numbers on all the labels will match the VIN plate of the vehicle. If the numbers do not match, it means the vehicle has been wrecked and the odd FATS number is from a salvaged vehicle. FATS labels are not reproduced and do not come attached to new replacement Original Equipment Manufacturer (OEM) body panels. However, with today’s technology, counterfeiting VIN and FATS labels is, of course, possible.

FATS Label examples are seen in Figure 9. The photos in Figure 9 show FATS labels on a Toyota fender and on a

www.collisionpublishing.com

Figure 9: FATS Label examples

Figure 8: Tapelines inside the fender edges under the hood, doorjambs or the quarter panels

Figure 10: where FATS labels may be placed by those vehicle manufacturers who use them

Honda hood with an information warning label. The diagram (Figure 10) shows where FATS labels may be placed by those vehicle manufacturers who use them.

•

Emissions information

•

Cooling information

Another potential indication of a previous repair might be the absence of “Under-the-Hood Information Labels.”

Information labels under the hood provide just that: information. However, these labels are not always attached to the underside of the hood, one may find them attached to the radiator core support or to other parts of the engine compartment. Examples of information which may be found on under-hood labels (as seen in Figure 11) includes:

•

Engine belt layout

•

Engine size

•

Recall campaign completion stickers and more

The Service Parts Identification label (example as Figure 12) is found on GM vehicles (not those of other manufacturers) and includes 3 digit Regular Production Options (RPOs) specific to a particular vehicle. RPOs are codes for many of the things that were done when a specific vehicle

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 43

Figure 11: Examples of information which may be found on under-hood labels was being built and are associated with a specific, individual vehicle by way of the VIN which is found on the Service Parts Identification label.

If the VIN from the VIN plate and the one found on the Service Parts Identification label don’t match, that can be a good indication of “used parts” or perhaps even a VIN switch on a repaired or salvaged vehicle.

Replacement parts, in particular body panels, often have an “R DOT Label” on them such as seen in Figure 16. Depending on the location of the R DOT label, many body shops will either remove or paint over it. Figure 16 shows an aftermarket body panel R DOT label. The manufacturer of this aftermarket body panel is TYK. This particular R DOT label was on the inside of a fender hidden by the splash shield.

Figure 12: Service Parts Identification Label The Service Parts Identification label – again specific to General Motors vehicles - is often found in the trunk either on the inside of the lid (Figure 13, right) or under the carpeting near the spare tire (Figure 14) in passenger cars.

It may also be found in the glove box or door jamb of light trucks or SUVs (Figure 15).

44

Collision Magazine - Volume 9 Issue 1

The vehicle manufacturers do not make aftermarket parts; parts from the manufacturer’s parts supply chain are referred to as “OEM parts.” Depending on whom one asks, the aftermarket parts used may be equal, better or worse in quality than original manufacturer parts (the original text of “Signs of a Wreck” includes examples of public statements by vehicle manufacturers such as GM regarding suitability of aftermarket parts).

The photos seen as Figure 17 are the underside of two 2007 Honda Odyssey hoods. The one on the left is the aftermarket hood, and the one on the right is the Honda OEM hood. The aftermarket manufacturer stamped its logo and part number on the hood, whereas the Honda OEM hood

www.collisionpublishing.com

Figure 13: The Service Parts Identification label (specific to General Motors vehicles)

Figure 16: “R DOT Label”

Figure 14: The Service Parts Identification label under the carpeting near the spare tire

Figure 15: The Service Parts Identification label in the glove box or door jamb of light trucks or SUVs www.collisionpublishing.com

Figure 17: Underside of two 2007 Honda Odyssey hoods Collision Magazine - Volume 9 Issue 1 45

had an information label and the FATS label. The photos in Figure 18 are of Honda Odyssey left fenders—an aftermarket and the Honda OEM original top and bottom, respectively. Sometimes R DOT stickers may be found behind other panels such as in Figure 19 where the sticker was seen on a bumper bar behind the bumper cover.

“Fit and Finish” is a term often used to describe how well parts of a vehicle are mated up or come together at seams or joints. A misalignment at a point where two parts come together (unless it’s associated with the crash being investigated or can be attributed to the “current crash”) can often be an indication of a prior repair. Bad “fit and finish” generally indicates a lack of attention to detail and precision during repair (although it can be found lacking on some new cars as well). It might even be an example of pre-existing and unrepaired damage however minor (as seen in Figure 20, the seam between the bumper cover and fender behind the headlight should mate up better than that).

Figure 20: seam between the bumper cover and fender behind the headlight Figure 18: Honda Odyssey left fenders—an aftermarket and the Honda OEM original top and bottom, respectively

Other examples of misalignment between panels on a previously repaired vehicle (Figure 21) and those same joints seen on a new, undamaged vehicle (Figure 22) are subtle but are potential indications of (a) parts that are out of adjustment, (b) improperly replaced parts or (c) aftermarket parts which don’t really match OEM parts well.

The repaired 2005 Ford Explorer seen in Figure 21 had an aftermarket bumper cover installed rather than a Ford OEM. Observe the difference in shape and fit in Figure 23. The upper portion of the aftermarket bumper cover is a little shorter and has a tighter fit to the right fender than of the OEM fender does. The rear edge of the aftermarket fender does follow the same curve as that of the Ford OEM bumper cover, but the upper bodyline in the aftermarket bumper cover does not meet the upper bodyline of the OEM left fender (Figure 24).

Figure 19: R DOT sticker on a bumper bar behind the bumper cover 46

Collision Magazine - Volume 9 Issue 1

Sometimes identifying a replacement bumper cover can be as easy as looking for masking tape or duct tape left on the vehicle after the repair as seen in Figure 25 (taken of a

www.collisionpublishing.com

Figure 21: Example of misalignment between panels on a previously repaired vehicle

Figure 22: Joints seen on a new, undamaged vehicle

Figure 23: Example of he difference in shape and fit

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 47

Figure 24: The rear edge of the aftermarket fender does follow the same curve as that of the Ford OEM bumper cover, but the upper bodyline in the aftermarket bumper cover does not meet the upper bodyline of the OEM left fender

Figure 25: Identification of a replacement bumper Jaguar XJ8). Along with this indication we find obviously inadequate fit between the bumper cover and fenders as seen in Figure 26 (of the same car).

Attention to detail is also evident where there are obviously missing parts. Where a small part could conceivably come loose or fall off, fasteners falling off a vehicle are almost unheard of. In Figure 27, we see the lower side of the bumper of the same vehicle seen in Figures 25 and 26 where one of the bumper fasteners is missing and there is no indication it was ever installed.

Similarly, all vehicles have front fender splash shields and those come in all shapes and sizes. You may need to turn the wheels to see any signs of missing or odd fasteners in the splash shields but finding that may indicate a repair from a previous crash. Full lower splash shields can and will hide prior damage made to a vehicle’s upper and lower

unibody frame rails and radiator support, so removal of the splash shield may be necessary for an adequate inspection.

Many vehicles will use a combination of plastic “push-in” fasteners along with “bolt-on” fasteners. Be prepared to either lie on the ground or find a garage with a lift so that they can raise the vehicle to remove the lower splash shield and inspect underneath. When you are checking underneath, make sure all the fasteners match up and none are missing (see Figure 28).

H

idden Damage Splash shields can mask significant inadequate repairs within the “crumple zone” on a vehicle. During the inspection of repairs made on a 2007 Acura MDX which reportedly had more than $12,000 in repairs made to the front-end and after removing the front lower splash shields, along with the right and left fender splash shields, the author found that front lower

continued on page 51 48 Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

ACCIDENT RECONSTRUCTION AND FORENSIC MAPPING SOLUTIONS DESKTOP MAPPING & ANIMATION SOFTWARE | EVIDENCE COLLECTION SOFTWARE & HARDWARE | TRAINING

WHEN YOU’RE LOOKING FOR THE BEST ACCIDENT RECONSTRUCTON SOFTWARE, YOU NEED TO LOOK AT

NOW WITH ADD-ON MODULES MapScenes Forensic CAD with your choice of point cloud and animation options to ensure you get precisely what you need.

FORENSIC CAD Law enforcement and accident investigators use MapScenes Forensic CAD. MapScenes Forensic CAD is the most precise desktop forensic mapping software available in the world. This powerful and feature-rich application provides law enforcement professionals and accident reconstruction specialists, like you, with confidence that the evidence they present is precise, compelling, and irrefutable.

Turn the page for more information about our powerful animation and point cloud modules.

ANIMATION FOR THE REAL WORLD

ANIMATION MODULE Full-featured forensic animation software for creating precise and compelling animations.

The animation module gives you incredible flexibility to accurately animate your scenes - look at your data in ways you never thought possible.

Our rendering capabilities give you the tools you need to analyze, edit, and build engaging animations.

Timeline and advanced object movement, animated cameras, real surfacing, vaulting and other physics tools - you will be amazed at the possibilites!

POINT CLOUD MODULE An incredible point cloud visualization tool to assist with mapping and animation.

Imagine being able to walk through a point cloud, in real-time, in order to complete your line work or conceptualize your dramatic re-creation.

With the point cloud module you can draw lines right in the point cloud viewer, which will show up in your CAD drawing. You can also include the point cloud itself in your final animation for added realism at NO extra effort. Mapping through to animating, your efficiency will soar!

LET THE SCENE SPEAK FOR ITSELF

is registered in the U.S. Patent and Trademark Office. All other brand ® MapScenes names, product names or trademarks are property of their respective owners.

www.mapscenes.com

1.800.668.3312

THE REST OF THE

SYSTEM

EVIDENCE COLLECTION SOFTWARE:

EVIDENCE COLLECTION HARDWARE:

CERTIFIED TRAINING:

Reduce errors, save time, and eliminate frustration.

Incredible hardware options and support.

When accuracy and precision are non-negotiable – there is MapScenes.

Evidence Recorder is the world’s best selling evidence collection software built specifically for the professional reconstructionist.

Using a Windows Mobile or tablet device, Evidence Recorder allows you to experience the power, precision and productivity gains associated with being able to visually verify your ongoing field evidence collection – on-the-spot, right in the palm of your hand. Then, for maximum results, it can seamlessly integrate with the MapScenes desktop software.

Evidence Recorder is supported with more total stations, data collectors, and GNSS receivers than ever.

Training is essential in all facets of law enforcement. MapScenes acknowledges its responsibility to the industry by ensuring that all trainers and educational courses are kept up to date through a base educational standard, preserving quality and integrity.

Combine with your existing hardware, or choose from one of our hardware bundles. Evidence Recorder is included on all hardware configurations and offers the absolute best in value.

We have set an industry benchmark by developing a comprehensive framework that provides investigators with the knowledge and skills required to use the MapScenes system easily, efficiently, and expertly.

Choose from numerous options, including: Nautiz X7, Algiz 7, Archer field PC, or Allegro MX.

THE

SYSTEM:

Evidence Collection Software Evidence Collection Hardware Desktop Mapping Software

is registered in the U.S. Patent and Trademark Office. All other brand ® MapScenes names, product names or trademarks are property of their respective owners.

www.mapscenes.com

Training

1.800.668.3312

Figure 26: Inadequate fit between the bumper cover and fenders

Figure 27: The lower side of the bumper of the same vehicle where one of the bumper fasteners is missing and there is no indication it was ever installed www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 53

Figure 28: Check the fasteners match up and see if any are missing unibody frame rails still had damage to both sides—they HAD NOT BEEN repaired (Figure 29).

to exterior panels such as door skins, roof panels, quarter panels and the rear body panel although they may be used to weld other panels if “recommended” by the vehicle manufacturer.

One alternative is “GMA” (MIG) plug welding. MIG Welding is generally considered an “easy task” and little training is required to become minimally competent to “MIG Weld.” Figure 32 depicts wholly inadequate manmade plug welds made on the Acura MDX example.

Figure 29: front lower unibody frame rails still had damage to both sides The left lower unibody frame rail also should have been replaced but had not been. On closer inspection, one will see (Figure 30) the remaining buckle in the unibody frame rail. Had this Acura MDX sustained a second front-end impact, the unibody frame rail would have failed to collapse as designed by the manufacturer. As a result, the air bag system may not have responded as designed and may have sensed the impact as a relatively softer impact resulting in deployment of the air bags later than designed or not at all.

Other indications of inadequate repairs which might significantly affect the strength of a vehicle in a subsequent collision include improper or omitted welds. What appear as circles in Figure 31 are factory spot welds that CANNOT BE DUPLICATED by body shops. Many body shops have a STRSW Welder (Squeeze-Type Resistance Spot Welder), and those cannot duplicate the same type and size weld as the vehicle manufacturer’s robotic welders can. STRSW welders are generally limited primarily 54

Collision Magazine - Volume 9 Issue 1

The Acura MDX repairs were made under the owner’s collision policy by the recommended repair shop of his auto insurer. The owner demanded a re-inspection of his Acura MDX by his auto insurer after repairs were completed and after the auto insurer representatives re-inspected the vehicle, they declared the Acura MDX a “total loss.” Of course, one might wonder how often this actually happens and, instead, how often that car would have been “back on the road” and then involved in the later crash the reader would be investigating and, in that later crash, how would the vehicle have performed in terms of crashworthiness not to mention the potential effect on the air bag system’s design criteria.

M

ore in the “Crumple Zone” Also within the “crumple zone” is the engine compartment where one can often find indications of a damaged then repaired vehicle including after-market fenders and hood, missing “FATS” or information labels, shims or flat washers under the fenders, or scars on the bolts securing the hood and fenders.

The majority of all bolts and nuts under the hoods of vehicles are “painted” at the factory. One should look for “scarring” of the paint on the hood hinge bolts and fender bolts. These “witness marks” are a quick way to spot signs of repair or replacement of the component being held in place by the scarred bolt. Sometimes a painter may try

www.collisionpublishing.com

Figure 30: The remaining buckle in the unibody frame rail

Figure 31: Factory spot welds that CANNOT BE DUPLICATED by body shops

Figure 32: Wholly inadequate man-made plug welds made on the Acura MDX example www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 55

touching-up the scarred bolt or nut but if one looks closely enough, scaring is visible (see Figure 33).

Some manufacturers place plastic moldings on an inside fender-edge or hinge which may cover up the bolts. This may hinder direct inspection of the bolts for possible scars (Figure 34) and require a little more effort to detect.

Although mentioned in the context of the bumper repair (Jaguar example, Figure 27), missing fasteners under the hood may be observed and would suggest a repair technicians in such a hurry that they forget to put the fasteners (bolts, nuts, screws and clips) in place. Compare similar right and left parts when you see that a bolt, nut or screw is missing. In Figure 35, we see the headlamp assembly which is normally secured to the radiator support by nuts but, by comparing the two, we can see that one nut is missing.

In some fashion or form, vehicle manufacturers will hide a portion of the radiator core support, which is located behind the front bumper and in front of the motor if only for apparent aesthetic reasons. The radiator core support secures the cooling system (radiator and air conditioning condenser) in place along with other front-end parts. There may either be a full front bumper cover, combination front bumper and plastic cover on the radiator support, or a partially opened area of the radiator support. Look to see if all of the fasteners match up or if any fasteners are missing.

Also look for scarring on any bolt heads. In Figure 36, we see a missing bolt.

Figure 37 is of a Toyota Camry upper radiator support that does not have a full bumper cover or plastic cover hiding the cooling system, in this case by design. Many parts are exposed for inspection to reveal possible repairs. Figure 38 is of a Honda Pilot with a full front bumper cover and a

Figure 33: Example of touching-up the scarred bolt or nut but if one looks closely enough, scaring is visible 56

Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

Figure 34: Some manufacturers place plastic moldings on an inside fender-edge or hinge which may cover up the bolts

Figure 35: headlamp assembly which is normally secured to the radiator support by nuts

Figure 36: Example of a missing bolt www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 57

plastic cover, again here by design. Looking closely at the cover and one will see the plastic fasteners securing the cover.

A

lignment Holes When inspecting a vehicle under the hood, check for parts that are out of alignment by looking for, among other things, “alignment holes.” Many vehicle manufacturers have alignment holes in the fenders and radiator supports. In the autobody-repair industry, the alignment holes serve as one of many measuring points used to check to see if the upper portion of the unibody frame is square, or aligned. In Figure 39, we see the right and left fender of a Toyota Tundra pickup that was involved in a left-side impact. Looking just above the fender bolt on each side of the vehicle we can see how the fender alignment holes match to the alignment hole of the radiator support (Figure 39). Note that the larger black hole is not used as an upper-body alignment point, it is an access hole for technicians. Here, the right fender is more in alignment than the left fender.

The left fender is slightly pushed inboard and needs to be pulled out so that the left fender and radiator support holes align properly. This Tundra’s radiator support is over to the right and needs to be moved to the left.

Figure 37: Toyota Camry upper radiator support that does not have a full bumper cover or plastic cover hiding the cooling system

Figure 38: Honda Pilot with a full front bumper cover and a plastic cover

In Figure 40, one can see that the hood of this vehicle is out of alignment by comparing the location of the leftside hood-hinge bolts to the right-side hood-hinge bolts and the gap (holes) around where the bolts are installed.

Whether or not one sees hood-hinge bolts appearing to be out of alignment, one should always perform the open and close test (assuming the condition of a vehicle permits this and is otherwise unaffected by the crash being investigated). Simply, open and close the hood slowly to see and feel if the hood latch closes evenly. When closing the hood, if you feel a noticeable push to the right or left when the hood striker locks in place to the hood latch, this can indicate prior repairs made to the front end of the vehicle.

P

rior Location of Parts and Shims Other indications of misalignment will be seen where bolt-on parts don’t match up with the original bolt-head position. Several vehicle manufacturers have listed tolerances for the fitting of bolt-on parts. The technician may bypass the tolerances and make the hole larger to achieve a better fit. Making adjustments like this can be an indication of hidden upper unibody damage. The photos in Figure 41 are parts that were realigned to fit. One can see the indications of realignment to make the parts fit highlighted and where the

58

Collision Magazine - Volume 9 Issue 1

Figure 39: Right and left fender of a Toyota Tundra pickup that was involved in a left-side impact

www.collisionpublishing.com

Figure 40: Hood is out of alignment by comparing the location of the left-side hood-hinge bolts to the right-side hood-hinge bolts and the gap (holes) around where the bolts are installed

Figure 41: Parts that were realigned to fit rust from the original bolt remains (even those not present in the photos!).

provide the reader with a better understanding of why and how shims and washers are used.

Vehicle manufacturers used to use metal shims under front-end bolted-on body parts to achieve a better overall fit. Today, vehicles are much more precise in terms of fit and finish, and if a vehicle manufacturer does use shims, they are not often easily noticeable. However, in the collision repair industry, shims and round flat washers are all too commonly used in repairing a damaged vehicle. Figure 42 offers an example the author created intentionally to

In this example, the author used washers to lift up the front part of the fender from the radiator core support as the radiator support is still down in the front. Had this example actually existed, it would have meant that other front-end structural parts were not installed properly, were not repaired properly and/or were still damaged. When one sees this type of “repair,” it’s very likely that there are other problems with the vehicle as a function of a previous crash and less than adequate repair.

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 59

lower “A-pillar” (or “front pillar”) by hinges. On four-door vehicles, the rear door hinges are attached to the structural “B-pillar” (or “center post” or “rocker panel”). Both the A-pillar and B-pillar serve as integral structural parts to a vehicle.

Figure 42: An example the author created intentionally to provide the reader with a better understanding of why and how shims and washers are used

P

illars, Hinges and Doors The automotive industry uses the term "pillar" for a body panel that offers structural support to other body parts. For example, the “A-pillar” at the windshield and “B-pillar” behind the front doors.

On all vehicles, regardless of whether they are two-door or four-door, the front doors are attached to the structural

There are two types of door hinges, “Bolted-on” and “Welded-on” (Figure 43, left and right respectively), used in the manufacturing of vehicles. Bolted-on door hinges are adjustable whereas Welded-on door hinges ARE NOT. Depending on the level of damage to the door and hinge pillar area and even the type of hinge, technicians may have difficulty achieving a good fit and alignment. One should compare all door hinges on the vehicle to ensure they are consistent.

Many times there can be indications of scarring on the bolt heads and/or an imprint of the former location of the bolt itself, due to either repair or replacement of the door. One may even see rust developing on the bolt head. The photos in Figure 44 show a door adjustment and rust on the bolt heads and witness marks from post manufacturing door adjustment.

Figure 43: Two types of door hinges, “Bolted-on” and “Welded-on”

Figure 44: Door adjustment and rust on the bolt heads and witness marks from door adjustment 60

Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

The two photos in Figure 45 are the left-rear door hinges of a 2002 BMW M5. BMW does install “shims” similar to these between the door and hinge, but not to this degree; not this many. This BMW was severely damaged on the left side, and the repair technician could not get the doors to align properly due to remaining problems at the B-pillar. While there might then be other problems that you may not be able to see, one has to wonder how this vehicle might perform in a side impact later.

Door edge seam sealers are designed to help prevent moisture from entering between the inner edge of the outer door panel and the doorframe along with other areas in a vehicle. Not all vehicle manufacturers apply seam sealer around the inside edge of the doors, so NOT seeing it shouldn’t be considered an indication of prior repair.

The photos in Figure 46 depict the difference between a replacement driver side door and an original passenger door.

In this example, the manufacturer DID use a seam sealer, as evidenced on the original passenger door. The repair technician installed a replacement driver’s door without applying the seam sealer. This kind of discrepancy could indicate other hidden damage and, again, a weakened state as it might relate to a later side impact.

The previously described Jaguar XJ8 had damage to the right side doors and both of its right side doors had the outer door panels replaced. Reapplying seam sealer so that it appears consistent can be tricky for even a good repair technician. This particular technician used masking tape around the edge of the doors when he applied the seam sealer, leaving a visible tapeline edge and inconsistent

Figure 45: Left-rear door hinges of a 2002 BMW M5

Figure 46: Example showing difference between a replacement driver side door and an original passenger door www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 61

thickness of the seam sealer (Figure 47). One should check inside all of the door edges to see if they are consistent.

When a vehicle is damaged on the unibody side of the A-pillar, B-pillar or a quarter panel, it may require a little closer inspection to detect prior repair. If one suspects that a unibody panel has been replaced, a good approach would be to pull the weather-strip seal down to check the welds as previously described (see also Figure 48, another illustration of factory welds). By comparison, in Figure 49, one may see a partial view of a unibody side panel of a 2007 Infiniti QX56 which was in a rollover accident and then repaired. The repair technician made the welds too far apart from each other indicating that there are fewer welds than were present originally, and did not finish smoothing the welds he did make.

In Figure 50, we can see that some spot-welded areas of a vehicle are easy to see, so it is not hard to spot a replaced panel. Compare the left photo from a 2007 Infiniti QX56 that was never damaged to the photo on the right of the damaged and repaired 2007 Infiniti QX56.

An improper repair or replacement of the A-pillar, B-pillar and/or quarter panel will cause the doors not to align or close properly and will affect bodylines and gap openings not to mention the potential impact on side strength and door integrity in a crash or rollover.

In the previously described rollover then repair of the 2007 Infiniti QX56, the repair technician did not properly align the doors. The inadequate repair is first detected by simply opening the doors; one would feel a “sag or drop” as the

Figure 47: Masking tape around the edge of the doors when he applied the seam sealer, leaving a visible tapeline edge and inconsistent thickness of the seam sealer 62

Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

Figure 48: Illustration of factory welds

Figure 49: Partial view of a unibody side panel of a 2007 Infiniti QX56 which was in a rollover accident and then repaired

Figure 50: Some spot-welded areas of a vehicle are easy to see, so it is not hard to spot a replaced panel

“

doors opened. When checking the other side of the Infiniti, the author detected the same problem/feeling. Check for “sag or door drop” by opening the door SLOWLY to see and feel if the door drops down. To detect misalignment, one should SLOWLY close the door to the point where it almost locks into place at the striker to see if the door raises up. In the example of the 2007 Infiniti QX56, the driver’s door had a “drop” in it when it opened, hitting the upper part of the rear door.

It might be easier to detect and is surely easier to show in photos if one were to use something as simple as a paint paddle as a simple gauge to measure the gaps between the doors. In the example of the QX56, the author could not insert the paint paddle between the doors of the repaired

The inadequate repair is first detected by simply opening the doors; one would feel a “sag or drop” as the doors opened

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 63

Infiniti (Figure 51, left image); however, it did go between the doors of the other Infiniti QX56 with no effort (Figure 51, right image).

As seen in the repaired versus undamaged (left and right respectively in Figure 52) the author also compared the door/fender gaps of the damaged and repaired 2007 Infiniti QX56 to another one lower down along the edges of the doors. Taking he paint paddle and placing it between the fender and door of the repaired Infiniti, the paddle slid only about halfway down the door and fender before it stopped. Doing the same test to the undamaged Infiniti the author was able to slide the paddle all the way down without any effort.

I

nterior Panels and Spaces Interior trim panels can hide inadequate or often wholly incomplete repairs, too. Figure 53 shows structural damage on the inner front A-pillar detected after removal of the right side trim panel which remains significantly distorted.

After seeing the condition of the right-front inner A-pillar, the author then removed the seats and other trim panels on the right side of the Highlander for a more thorough inspection. Keeping in mind that the B-pillar is a structural part of the vehicle, in this case, it turned out to be one of the weakest points after “repair.”

The body shop technician sectioned the B-pillar’s outer, center and inner panels, replacing them with only a small portion of other B-pillar(s) rather than the whole parts, as required for a proper repair. In Figure 54, between the areas of the “red lines” one can see this “repair.” With this

type of inadequate repair, if the vehicle were involved in another impact or rollover, it’s entirely possible if not likely that the right side could collapse faster than designed by Toyota, possibly causing the side-impact airbags not to deploy in time - or at all - endangering the person riding in the right-front and right-rear passenger seats not to mention the effect of the now reduced roof strength.

Q

uarter Panels and the Trunk When looking the vehicle over, one should check all gap openings and bodylines to the quarter panel and door, quarter panel and trunk lid and/or rear hatch; previously described as “fit and finish.” If a repair technician does an inadequate job, poorly installed or repaired panels should be immediately evident.

On cars, compare the upper edges, the quarter panel and trunk lid for proper alignment. On SUVs, compare the height to see if the hatch is higher, lower or flush with the quarter panels. Compare the gaps on both sides of the trunk lid or rear hatch down to the rear bumper. Open the trunk lid or rear hatch, then slowly close it to see if it pushes either to the right or left or closes easily.

Figure 55 is a pair of photos of a 2005 Lexus 330 that had repairs made to the left rear. The replaced trunk lid had a noticeable push to the right after opening and closing it several times. The gap is even more pronounced in Figure 56. The rear bumper cover does not match up gap wise to either the right or left side of the rear tail lamps.

Below are close-up views of the left and right rear section of the quarter panel / rear-body panel water trough, of the

Figure 51: Using a paint paddle as a simple gauge to measure the gaps between the doors 64

Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

Figure 52: Comparison of the door/fender gaps of the damaged and repaired 2007 Infiniti QX56 to another one lower down along the edges of the doors

Figure 53: Structural damage on the inner front A-pillar detected after removal of the right side trim panel which remains significantly distorted

Figure 54: Replacement with only a small portion of other B-pillar(s) rather than the whole parts

Figure 55: Photos of a 2005 Lexus 330 that had repairs made to the left rear www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 65

Figure 56: Photos of a 2005 Lexus 330 that show a gap that is even more pronounced Lexus. Compare both sides, and you will see seam sealer “brushed on” the left side and none on the right side. This is an indication of either a recently replaced or repaired left quarter panel. The rear-body panel is welded to both right and left quarter panels and rear trunk floor pan.

Inside the trunk one might see where seam sealer has been “brushed on” on the left side and not on the right side (Figure 57). This is an indication of either a recently replaced or repaired left quarter panel. The rear-body panel is welded to both right and left quarter panels and rear trunk floor pan. The photos in Figure 58 are from the water troughs of the previously described 2007 Infiniti QX56 (left) and that of an undamaged 2007 Infiniti QX56 (right). One can easily see the difference in the seam sealer between these two examples.

T

ruck Beds Repaired damage to pickup trucks should be easy for anyone to see once they know what to look for. Perhaps one of the easiest places to see a previous repair or a less than ideal condition of the truck bed is to examine the space between the cab and the leading edge of the bed (Figure 59). One should compare the apparent space on the left with that on the right.

Looking again for tape lines, sanding marks, and overspray, removing the seam sealers such as those found at the tailgate (Figure 60) and looking for appropriate (factory) welds as opposed to those previously described would be an indication that repairs have been made to the bed and/ or tailgate.

Bumper alignment on trucks is another area where the investigator might be able to detect a previous repair which might involve the frame in addition to the bed of the truck.

Care should be given to be sure that the misalignment isn’t 66

Collision Magazine - Volume 9 Issue 1

simply a function of the bumper’s alignment independent of any other damage.

H

idden Dangers As previously discussed, splash shields, interior trim panels and other trim panels can hide poorly repaired or improperly replaced structural parts. The 2005 Lexus 330 previously mentioned had hidden dangers after it was considered “repaired.” The author also found that the left quarter panel had been “glued on” around the “mating flanges” of the quarter panel and outer wheelhouse panel. The Toyota/Lexus and Honda/ Acura Motor Companies clearly state in repair and service literature that “the quarter panels are not to be glued or adhesive bonded; they are to be welded on.” They go on to add that gluing or adhesive bonding is considered “reengineering the design of the vehicle’s structural integrity.”

Yet many auto body shops throughout the U.S. continue to glue quarter panels in place.

Gluing or bonding can be detected with a careful examination of the joints between panels and parts. As seen in Figure 61, one can easily see how the glue oozed out around the quarter panel and outer wheelhouse mating flanges and was then painted over. Figure 62 shows how the quarter panel should look around the wheel opening when factory welds have been applied.

In the context of a crash, it doesn’t take much to contemplate the difference between parts glued together and those welded to a factory spec when considering how the vehicle components will hold up in a crash.

When the wheelhouse inner-liner of this vehicle (Figure 62) was removed, the author found the outer wheelhouse still damaged. This is a structural panel, and - following proper repair process - it MUST BE “restored back to the

www.collisionpublishing.com

Figure 57: Inside the trunk one might see where seam sealer has been “brushed on” the left side and not on the right side

Figure 58: See the difference in the seam sealer between these two examples

Figure 59: Space between the cab and the leading edge of the bed

Figure 60: Removing the seam sealers such as those found at the tailgate

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 67

Figure 61: Quarter panel and outer wheelhouse mating flanges and was then painted over

Figure 62: Outer wheelhouse still damaged original shape and form for structural integrity and crashworthiness.” In the event of another rear-end impact, this outer wheelhouse will collapse faster than it should, when compared to the original Toyota/Lexus design. In Figure 62, in the around the green circle, one will see the damaged outer wheelhouse panel as it was found “after repair.”

While it seems only logical that parts glued together can’t be as strong as those welded together, that doesn’t address when the welds aren’t done according to factory spec. Figure 63 depicts the area where the back glass seals to the quarter panel. When the repair technician replaced the left quarter panel, he made only six welds to it instead of the 11 factory welds made by Lexus; standard for the same area. The dark areas in the figure near the back glass are “weld burns.”

In the example depicted in Figure 64, depicting the inside the doorjamb of the described Lexus, the author counted 15 of the repair technician’s welds against 22 factory welds

70

Collision Magazine - Volume 9 Issue 1

made by Lexus. The repair technician is probably completely unaware that this Lexus will not react as designed in another rear-end crash after he unwittingly “re-designed it.”

In the photos in Figure 64, the author marked holes that needed welds with a black arrow. The dark gray discoloration is bare metal.

U

nderside Uniformity and Structural Integrity While the narrative thus far has focused largely on panels and identifying inadequate surface repairs, the underside of the vehicle can be a source of evidence of inadequate repair and associated weakening of the vehicle structure. Identifying under vehicle repairs and the potential for weakened structural vehicle integrity.

All vehicles have their own distinct uniform appearance on the underside, from front to rear. The factory undercoating and seam sealers are applied in a uniform fashion. The un-

www.collisionpublishing.com

Figure 63: Area where the back glass seals to the quarter panel

Figure 64: Holes that needed welds with a black arrow

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 71

derside is generally painted the same color as the outside, but with a flatter finish. Very few body shops attempt to match the underside of a vehicle after repairs. The “quick fix” for the underside of the vehicle by most body shop technicians is to using an aerosol can of black undercoating, to get the vehicle out the door.

Figure 65 is the underneath-side floor pan of the previously described 2005 Lexus 330. The original underneath paint color is flat gray and white from the front to the rear of this Lexus. Here is a clear example of the lack of uniformity performed by a repair technician. The 2005 Lexus 330 had a portion of the left rear frame and the entire trunk floor pan replaced. The repair technician sprayed black undercoating on everything from the rear suspension to the back of the trunk floor pan. The small amount of white paint on the trunk floor pan came from the painting of the rear-body panel (Figure 66).

The repair technician who worked on the Lexus previously described at least tried to cover up his inferior quality work, but others don’t. The photos in Figure 67 show work performed by other auto body technicians, who did not even attempt to cover up the mess they created, probably assuming no one would look. Rust inside weld burns and sheet metal screws and holes which remain not welded make clear the inadequacy of the repairs.

Figure 65: Underneath-side floor pan of the previously described 2005 Lexus 330

Black undercoating and the associated potential for overspray of that undercoating material onto adjacent components can be an indication of an attempt to hide sloppy repairs (Figure 68).

Finding the signs of frame repair is not that difficult on many frame vehicles whether a car, truck or SUV. When re-aligning a unibody frame or full frame, the vehicle is secured in-place by four “clamping fixtures” (two seen highlighted in Figure 69). On unibody frame vehicles the clamping fixtures or clamps are attached to the lower part of the rocker panel called the “pinch weld.”

The clamp marks this sort of repair may be very visible, depending on the amount of pressure applied to secure the unibody clamping fixtures to the rocker panel-pinch welds. The clamping fixtures will leave either “horizontal, round indenting or slash” marks in the rocker panel-pinch welds. Figure 70 compares a slash mark with the clamp.

Often, auto-body technicians do not take the time to repair the clamp marks or scars. If they do, they usually spray them with black undercoating. Special clamping fixtures secure several European vehicles in place such as the Mini Cooper, BMW and Mercedes, and in those cases, there will not be any signs of clamp marks. BMW

72

Collision Magazine - Volume 9 Issue 1

Figure 66: The small amount of white paint on the trunk floor pan came from the painting of the rear-body panel

www.collisionpublishing.com

Figure 67: Work performed by other auto body technicians, who did not even attempt to cover up the mess they created, probably assuming no one would look

Figure 68: Black undercoating and the associated potential for overspray of that undercoating material onto adjacent components can be an indication of an attempt to hide sloppy repairs

Figure 69: Vehicle is secured in-place by four “clamping fixtures” www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 73

and Mercedes require their vehicles unibody frames to be aligned on either a Car Bench, Celette or CAR-O-LINER system.

Full-frame truck and SUV clamp and hook marks are generally simple to repair or cover; however, the telltale signs will still often be there. Look for black undercoating or black paint sprayed in the area that the clamping fixtures were located. If over-tightened on application, the clamps may also have left noticeable dent(s) in the frame.

All frames, whether they are uni-body or full-frame vehicles, MUST BE RESTORED back to the original shape and form, When they are not restored back to their original shape and form, then their “crash worthiness” is clearly compromised. Think of it this way, if you bend a piece of metal and then push on it again the same way, it’s easier to bend the second time, once it’s already bent.

Figure 71 is a photo of a 2007 Honda Accord right-rear unibody frame rail. The auto-body shop did not completely repair all of the frame damage. The black vertical line between the white round dots indicates a “buckle” in the unibody frame rail. The other black vertical line located between the two white vertical lines is where the auto-body shop replaced a “section” of the unibody frame rail. As with our previous examples, if this vehicle were to sustain another rear-end collision, this frame rail would not perform as designed by Honda engineers and could possibly “collapse faster,” causing other systems to not react or fail due to the buckle.

C

ase Example The author found himself involved in a “failure to disclose (damage)” case involving a Subaru WRX which had mismatched VIN plates and stickers and there was the suggestion of inadequate repair to the vehicle as a function of a crash involving the left front area of the vehicle.

The author examined the vehicle and observed and identified several areas of substandard or wholly inadequate previous repair. Included in that examination, he identified that the body shop repaired the vehicle from the initial crash with parts from a salvaged vehicle (obviously with a different VIN) leaving the other vehicle’s VIN parts on some of the components which were in conflict with the VIN plates on original components of the vehicle.

Further examination revealed incomplete parts replacement, inadequate welds (in terms of quantity and location) and frame components left damaged among other flaws. Where the “repaired” vehicle was declared a “total loss,” the author was able to secure it for subsequent

74

Collision Magazine - Volume 9 Issue 1

Figure 70: Comparison a slash mark with the clamp

Figure 71: 2007 Honda Accord right-rear unibody frame rail testing in an effort to demonstrate the effect of the inadequate repair.

The actual vehicle was used in a pair of crash tests at the ARC-CSI Crash Conference where observations regarding the post test condition make clear the effect of the inadequate repairs.

C

onclusion The author hopes that some of the information found in this excerpt of “Signs of a Wreck” will be useful to crash investigators who may, when examining an involved vehicle, identify indications of prior damage and subsequent potentially inadequate repair which might play a role in the evaluation of a post-repair crash.

www.collisionpublishing.com

While common sense tells us that an improperly or inadequately repaired vehicle wouldn’t have the same properties as a vehicle in its original condition, quantifying that in some way requires testing that isn’t generally done. The follow up to this excerpt of the author’s larger discussion will review one such test.

be some sort of “number” one can assign broadly to these deficiencies in the previously “repaired” vehicle, the very knowledge of such condition should give the investigator some basis for better understanding the “why” or “how” of certain aspects of a crash.

Crash investigators should be able to use the information here together with information from the crash test to evaluate the potential for structural or performance related deficiencies in a case vehicle. While there may not

SIGNS OF A WRECK Testing and Simulation Rusty Haight and Sean Haight Collision Safety Institute With Contribution from:

Dan H. Wyatt

Collision Service Investigators of North Carolina, LLC.

I

ntroduction The accompanying article “Signs of a Wreck” in this issue of Collision describes various repair techniques some of questionable value or effectiveness - and what the crash investigator may look for in an effort to identify a vehicle which has been subjected to a previous collision then less than adequate repair with an eye toward better understanding the vehicle’s performance in a subsequent crash. The follow up to that would be: what is the potential net effect of the less than adequate repairs on various components and systems of a “previously repaired vehicle,” particularly on with less than adequate repairs?

This companion article first examines the potential for quantifiable differences in a direct comparison between a test with the full suite of factory spot welds and a vehicle with missing spot welds (similar to the Subaru WRX). To accomplish such a comparison, without having to physically conduct additional pre-tests, Finite Element simulation tools were used.

By way of a second type of evaluation, the Subaru WRX mentioned as the “case example” in the primary article (“Signs of a Wreck”) was used in two crash tests at the

2014 ARC-CSI Crash Conference. While there is no full scale crash test to compare these tests with, observations about the condition of the vehicle after the crash test are valuable in light of the observations made in the simulation and the suggestions found in “Signs of a Wreck.”

M

ethodology For the simulation phase of this evaluation, the LS-DYNA Finite Element code was used to simulate two vehicle to barrier tests: one control case with all of the factory spot-welds in place, and one test case with some spot-welds removed from the main frontal frame rail beam. Because a Subaru WRX Finite Element model was not available, a 2010 Toyota Yaris model (Figure 1) was available from George Mason University’s Center for Collision Safety and Analysis (CCSA). Notably, the simulation offered isn’t offered to test the performance of this particular, specific vehicle, rather, to examine the theory advanced in “Signs of a Wreck” and as suggested by some of the manufacturer statements referenced in that article that inadequate repairs and/or aftermarket parts might impact a vehicle’s crashworthiness in a subsequent

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 75

crash. The Yaris was then selected as a similar class vehicle from those available from the CCSA database.

This particular model was reverse engineered, by hand, and validated for frontal crash test configurations (Marzougui et. al., 2012). The reverse engineering process for this model was completed by creating physical scans of each vehicle component, using the scan data to create finite elements, locating and assigning component connections (such as bolts and welds) and conducting material tests and applying those results to each component. In total this model contains over 977,000 elements connected by over 998,000 nodes. It is important to note that the welds in this simulation were modeled as beam elements that do not include failure criteria. In other words, the welds are not designed to fail and vehicle components will not separate at the location of the spot weld. Because of this approximation, the actual deformation could be slightly greater in an actual crash test. Similarly, there is no information available regarding the performance of the joined/ welded components done using other than factory methods during a follow up repair. The comparison here is then based solely on the presence of versus the lack of welds in the “stock” versus what would be called the “repaired” or “non-stock” condition.

The control simulation was configured to replicate a NHTSA Frontal NCAP crash test (Figure 2). For this simulation, all of the factory spot-welds and connections were intact and the vehicle was left in stock condition. The impact speed was 35 mph (56 km/h) and the vehicle was oriented so that it impacts a rigid NCAP barrier at zero offset and angle.

The test case was configured in the same way as the control case, but with some spot welds missing from the frontal frame rail support. In order to replicate an inadequate repair scenario as described by Wyatt in “Signs of a Wreck,” the stock welds to be “removed” (from the simulation) were

Figure 1: 2010 Toyota Yaris Finite Element model 76

Collision Magazine - Volume 9 Issue 1

selected so that there was an evenly distributed reduction of welds over the length of the structural member. Simply put, every other weld along each side of each frontal frame rail was removed from the model. This method of weld reduction resulted in a removal of 12 out of 30 total welds for each front frame rail beam (Figures 3 – 5). The full vehicle model has approximately 4500 OEM weld connections/points. In the underlying Subaru case example, there were 19 MIG plug-welds found in in the area of the left front door of the WRX where there would have normally been 38 factory spot-welds in the same area (Figures 6, 7 and 8).

For this evaluation, while the type of weld can’t easily be compared as previously discussed, it was theorized that changing the quantity alone might provide insight into vehicle performance after such a repair assuming the strength of an individual weld in the simulation wouldn’t change from one run to the next although the quantity of welds would. In the simulation, the welds won’t fail; they remain connected regardless of the deformation. If “real world” welds were/are in some way “inferior” to OEM welds; if they were to fail “easier” than OEM welded points, then one could easily assume that area of the vehicle to be further weakened (more than by reducing the number of welded points alone).

O

bservations form the Simulations Given assertions in the Wyatt article, one might theorize that the reduction of spot welds in the test case might result in (a) a different deformation pattern in the frame rail, (b) an overall increase in peak acceleration, and (c) an overall reduction is energy absorption during the crash. Quantifying that would then be the goal of the comparative simulations. A visual evaluation of the performance of the vehicle structures after an actual crash test on the “repaired” Subaru would follow.

Figure 2: Simulation configuration (NCAP)

www.collisionpublishing.com

Figure 3: Frontal frame rail beams for 2010 Toyota Yaris

Figure 4: Original spot weld configuration

Figure 5: Reduced spot weld configuration www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 77

First, the deformation pattern of the frame rails can be visually analyzed. Figures 9 and 10 are comparisons of the two configurations at 90ms after impact.

One can clearly see, based on a visual comparisons of the components in the two simulation cases alone, that there is a considerable difference in the deformation pattern of the frontal frame rail beam component. Since this change in deformation pattern could alter the shape and magnitude of the crash pulse, a comparison of the simulation crash pulse data would might next be examined. Figure 11 shows the comparison of the crash pulse for each of the simulations.

The crash pulse comparison clearly shows that there is a difference in the overall shape of the acceleration during the crash particularly in the time period starting at about 20ms through about 45ms. While the overall duration of the crash pulse is essentially the same, the peak acceleration at the center of gravity is different.

Figure 6: Only 19 MIG plug-welds were made versus 38 factory spot-welds in the same area on the right side

As it relates to the assertions found in the “Signs of a Wreck,” the slope of the projected acceleration in the 2045ms period - that period when an airbag control module would typically be likely to deploy front airbags - is notably different. Where an airbag control module looks at the developing crash pulse in the range of 15 to 50ms in a typical barrier test, the change noted in this simulation suggests a “softer” crash during that time frame. In fact, in the simulation where the spot-welds had been removed, acceleration is markedly less than in the simulation where the original spot-welds would remain in place. Keeping in mind that the weld properties between the simulations remained the same from one to the next, only the quantity changed, if, in a case vehicle, the quality of the welds in a “repaired” vehicle were to be “less effective” than in the OEM vehicle, the difference noted between these two simulations suggests there might be an even greater disparity in the observed acceleration levels.

Figure 7: Weld burns

Figure 8: More weld burns on the under side of the left upper frame rail 78

Collision Magazine - Volume 9 Issue 1

The maximum acceleration for the full spot weld configuration simulation is 52.5 g. The maximum acceleration for the reduced spot weld model is 56.9 g. This corresponds to a difference of roughly 7.5% between the two configurations. This difference may or may not have a significant impact on occupant safety. However, it does show that a poor repair which does not include the full array of spot-welds could increase the acceleration in the vehicle and the occupant.

While the peak accelerations occurred at about the same time, the magnitude of the peak g’s is, as noted, different but also different is the slope between the previously mentioned 20-45ms period and peak acceleration. If we were

www.collisionpublishing.com

Figure 9: Visual comparison of full spot weld configuration (left) and reduced spot weld configuration (right) at 90 ms after impact

Figure 10: Top view visual comparison of full spot weld configuration (left) and reduced spot weld configuration (right) at 90 ms after impact (right side rail)

Figure 11: Comparison of the CG acceleration pulse for the full spot weld configuration (black) and the reduced spot weld configuration (red) www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 79

to adopt that a primary criteria for deployment were the changing slope of the acceleration pulse in a given crash and the slope in the 20-45ms period were essentially “positive” (or “less negative”) then a deployment might be delayed as much as 10-20ms between these two simulations.

ously conducted crash test involving a vehicle of this type was at a higher closing velocity to a barrier and, while one might make some notable comparisons, a reasonable direct comparison given the differences in the test speed would be less valuable.

A comparison of the overall internal energy of the vehicle can be plotted and compared for each load case as well.

Figure 12 shows that there is, at its widest divergence, about a 4% difference between the two simulation configurations. The largest difference occurs at 30ms, where the frame rails are being deformed the most. At this time step, the difference in internal energy is 2812 Joules. Since the primary purpose of these components are to absorb energy at a specific rate and magnitude, changing the OEM configuration/quantity of the spot-welds clearly has an effect on how the vehicle distributes the energy during a crash.

It is possible that this difference can have an effect on the occupant, especially during the 20 to 50ms range where the occupant would be beginning to move toward contact with vehicle components and airbag deployment would most probably be anticipated.

In the second test configuration, the Subaru was stationary, struck in the driver’s side by a Crown Vic. This matched the previous damage area on the Subaru; “previous” as in before the repairs deemed “inadequate” by Wyatt in “Signs of a Wreck.”

F

ull Scale Crash Test Observations Specific to the Subaru WRX mentioned in “Signs of a Wreck,” that particular “repaired” vehicle was used in a pair of crash tests at the 2014 ARCCSI Crash Conference. The first test was a full frontal barrier test with the Subaru striking the barrier at 20mph (32km/h). The affected area on the Subaru didn’t extend beyond the front wheels and the main area of inadequate repair was the door sill/body panels at the left/driver door (Figure 13). The only available comparison with a previ-

In this test, there were two notable characteristics. One had to do with the apparent strength of the door frame around the driver’s door in the area of the repairs made as a function of the MIG welds done during the repair after the Subaru’s original crash and the other, associated effect, had to do with the deployment of the driver’s side (torso) airbag.

Figure 14 shows one of the areas on the Subaru where there were fewer weld points made during the inadequate repair after the initial crash and before the test. Only one of the four visible weld points had been welded during the “repair” and it remains intact whereas the areas where there were no welds have demonstrably separated. Similarly in the comparison shown in Figure 15 (a “before” and “after” of the same area on the Subaru showing painted over repair weld points), the attached components have separated along the repair lines.

In Figure 16 one can see the driver’s side bag. While it clearly deployed in the crash test, it is also very clear from the photos that at least the lower portion of the bag has

Figure 12: Comparison of the energy absorption for the full spot-weld configuration (black) and the reduced spot-weld configuration (red) 80

Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

Figure 13: Main area of inadequate repair was the door sill/body panels at the left/driver door

Figure 14: One of the areas on the Subaru where there were fewer weld points made during the inadequate repair after the initial crash and before the test www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 81

Figure 15: Comparison of “before” and “after” of the same area on the Subaru showing painted over repair weld points

Figure 16: Driver side airbag 82 Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

been pinned or restricted by the intruding door and frame area – the area subjected to less than adequate repair.

While there is no information available related to the specific timing of the side airbag, it’s clear that the intrusion into the side of the Subaru was such that the deployment was restricted at least at the lower portion of the bag if not also toward the top where marking on the interior of the door suggests the limits of the forward expansion of the side bag to be about even with the side “wings” on the driver’s seat. Given the observations made previously about the weakened state of a vehicle with fewer welded points than would be “stock,” and the fact that the area in which this intrusion is observed was left with fewer weld spots than anticipated by the OEM, the logical conclusion would be that the magnitude of the intrusion was greater than it would have been had the vehicle been “intact” (stock).

C

onclusions Between the simulations and the observations made of an inadequately repaired vehicle after a crash test, it’s clear that inferior or inadequate repairs – specifically including here inadequate weld points in quantity if not quality – effect the performance of a vehicle in a subsequent crash. The difference observed in

terms of acceleration measured at the center of gravity, the energy absorption and observations regarding the separation of structures and restriction of the side airbag in the test suggest that inadequate repairs can play a significant role in the safety of a “repaired” vehicle.

While crash reconstructionists often “assume” a vehicle is in a sufficiently similar condition when involved in a case collision as its sister vehicle would have been during a test (on which, for example stiffness coefficients might be based), that might not be the case. The information found in “Signs of a Wreck” may then be useful in determining if a given vehicle had been subjected to inadequate repairs; however, it would still be left to the reconstructionist to evaluate the quantitative or qualitative effect of the vehicle’s condition on their analysis.

R

eferences 1. Dhafer Marzougui, Randa Radwan Samaha, Chongzhen Cui, Cing-Dao (Steve) Kan, Kenneth S. Opiela. "Extended Validation of the Finite Element Model for the 2010 Toyota Yaris Passenger Sedan". Working Paper # NCAC 2012-W-005. July 2012.

Validating Crash Data Retrieval Tool Data thRough Crash Testing James D English James D English and Associates

S

ooner or later everyone in the collision ence, and move methodically through how your reconstruction world will find themselves investigation was performed and your foundation testifying in a deposition or on the witness for your conclusion, but what about a question stand offering an expert opinion about how along the lines of “How has the CDR Tool been a given crash occurred. Whether on the private side validated?” or the law enforcement side, there’s a point where As your mind starts to race on how stall for a few each of us will research and prepare for just about precious seconds and how to answer, you may wonany question. But no matter how well we prepare der, is he asking about the “validation” of the CDR or try to predict what questions may be coming, Tool itself, about the “validation” data recorded there may still be something coming “out of left in the module, or could it be the “validation” of field” that we may not have thought of. You can source of the data?

86 Collision Magazine - Volume 9 Issue 1 www.collisionpublishing.com handle questions about your training and experi-

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 87

P

rocess When an automobile manufacturer (OEM) designs a passenger vehicle such as those supported by the Bosch Crash Data Retrieval Tool, specifications for the supplemental restraint system (SRS) are set forth to ensure safety, functionality and meet regulatory compliance. The OEMs rely on and work with their first tier suppliers to design and test the various module(s) and the suppliers then work closely with the OEM to ensure their control module is performing to specifications laid out by the OE as it related to it recognizing a physical occurrence, sensing a crash and making an appropriate deployment decision.

When appropriate, recording data to the EEPROM within the module is ultimately a matter of whether or not the binary data - the 1’s and 0’s - has been recorded when/as appropriate. The data recording function within the module is part of the supplier’s responsibility to the OE. The supplier works with the OE on the module/vehicle interface and “validation” of this aspect of the final data product extends to ensuring whatever data the module had in RAM was recorded properly when that module “becomes an ‘EDR’.”

Bosch designs the CDR Tool – essentially a scan tool – to communicate with an appropriate module(s) in a passenger car, light truck or SUV. Most of the functions of the CDR Tool are basically those found in other scan tools.

The Tool takes advantage of industry standard communications protocols and routines to access and retrieve data from supported modules.

The CDR Tool supported OEM’s provide Bosch with a set of specifications describing the desired function of the CDR Tool relative to that OEM’s system(s) to be supported. Bosch implements the specifications and together they test the functionality of the tool to access and retrieve the module’s recorded data and translate it according to the OE’s specification(s). Bosch’s “validation” of the CDR Tool in this respect relates then to ensuring that the Tool functions as called for in the OEM’s specification in terms of communicating with the module(s), retrieving the specified data elements, and then translating and reporting that translation properly.

Bosch’s “validation” of the performance of the Tool does not relate to the underlying accuracy of the data in an OEM’s module(s) and Bosch isn’t involved in anything that relates to what goes on in the vehicle/module(s) before retrieval.

In evaluating the underlying retrieved data (vehicle speed, delta-V, belt use, for example), other aspects might be ad88

Collision Magazine - Volume 9 Issue 1

dressed separately meaning that the data transfer within the vehicle, reception of the data by the module(s), and the function of recording within the module all take place prior to the Tool’s retrieval process. For example, a signal from a sensor travels across the vehicle’s communication bus to a control unit which then processes the signal then uses the result on the output side. The signal output is then received by another unit. Crash data output is generally held in RAM in a Tool supported module until the EDR function calls for it to be recorded.

A simple example might be when a car door is left open.

The “Door ajar warning switch” is “open.” The sensor’s “open” signal gets to the Body Control Module (BCM), where it is directed to the dash to turn on the “door ajar" warning lamp. In some Tool accessible modules, that signal is also received by the module as an element to be held in RAM in case a recording is triggered.

For most other meaningful data elements in a CDR report, the process is essentially the same. With an understanding of the process, we can better evaluate the reliability of the data by comparison to crash test data and can determine the degree to which the data is an accurate representation of the “real world.”

That evaluation encompasses: • • • •

original sensor(s) functioning properly control unit(s) using the sensor information properly module(s) recording the data properly CDR Tool retrieving and interpreting the data properly

This article will look at some data parameters from crash tests comparing the retrieved data with external control instruments or other “real world” direct observations. In a sense, this approach addresses all three potential interpretations of the “lawyer’s question”

H

istory Over the last 14 years, the Bosch Crash Data Retrieval Tool has increased in popularity and is an invaluable tool in crash reconstruction and analysis. Today, with about 110,000,000 CDR supported vehicles on the roadways, it has become an important component in collision analysis. In addition to the countless hours that OEMs and Bosch have invested to design, test, and validate the results translated and reported by the CDR Tool, there have been a number of independent projects to validate those results through crash testing. This article will examine the results of 18 such crash tests, and compare the data parameters reported by the CDR tool

www.collisionpublishing.com

to data collected by external instrumentation and visual observations.

For the last 12 years, fully instrumented vehicle crash testing has been performed at the annual ARC-CSI Crash Conference held in Las Vegas. During the conference, all available modules in the test vehicles are imaged during pre-crash preparations. The vehicles are then fitted with precision instrumentation as well as both high-definition and high-resolution cameras. Virtually hundreds of still pre-crash and post-crash images are taken as well. The carefully planned crash tests are then performed and well documented. The modules are again immediately imaged to retrieve any recorded crash data. The CDR data parameter results are analyzed and compared to data captured and reported by the external instrumentation. The data is also presented and distributed to conference attendees.

For this study, tests from several ARC-CSI Crash Conference test series as well as crash test data from the Insurance Institute for Highway Safety were examined. Specific data parameters were studied and compared where applicable.

Not all of the tests captured and/or reported all of the chosen parameters. Only data points that could be fully

Test # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Model Year 2007 2005 2011 2005 2006 2011 2011 2013 2013 2014 2013 2013 2013 2014 2007 1998 2007 2007

Make Toyota Chevy Chrysler Chrysler Buick Jeep Chevy Chevy Dodge Fiat Buick Chevy Ford Jeep Toyota Saturn Ford Ford

corroborated or compared were reported here. Some of the parameters reported by the CDR Tool were able to be compared to external instrumentation, while some were only able to be compared to observations by either the vehicle operator or crash test staff. In the IIHS tests studied, data was compared with IIHS data tables and reports while observations were made using digital images from which the parameter could be clearly observed.

Time-series values, such as pre-crash vehicle speeds, reported in the EDR data and retrieved using the CDR Tool were compared with the reported data from external control instrumentation. Some allowance had to be made for resolution differences between the two instruments. The data parameters with discrete values, 1’s and 0’s, such as seat belt parameters, “buckle switch position,” were also examined. The EDR data collected was compared against direct observations by the operator and crash team members The following vehicles were randomly chosen for the study based on what data was captured and reported out by the CDR Tool and what data parameters were available for comparison with external data and/or observations.

Tested Vehicles Model Test Location Yaris ARC-CSI Impala ARC-CSI Town & Country ARC-CSI 300 ARC-CSI LaCrosse ARC-CSI Grand Cherokee ARC-CSI Volt IIHS Spark IIHS Dart IIHS 500L IIHS Encore IIHS Malibu IIHS Escape IIHS Grand Cherokee IIHS Yaris ARC-CSI SL7 ARC-CSI Crown Vic ARC-CSI Crown Vic ARC-CSI

Test Type into barrier into stationary bus as stopped vehicle head-on with Pontiac vs parked vehicle rollover into barrier (40% overlap) left side 90° impact left side 90° impact into barrier (40% overlap) left side 90° impact left side 90° impact into barrier (40% overlap) into barrier (40% overlap) into barrier into stationary bus into stationary vehicle into moving vehicle

Table 1: Test Vehicles Selected

www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 89

The following data parameters were examined and compared: • • • • • • • • • • • • • • • • • • • •

Speed, Vehicle Indicated @ T0 Accelerator Pedal Position (% or V) Engine RPM Brake Switch Status Buckle Switch - Driver Buckle Switch - Pass Passenger Occupant Status Driver Seat Position Ignition Cycle @ Crash Ignition Cycle @ Investigation SIR / SRS MIL status Cruise Control Shift Position Frontal AB - Driver Frontal A/B - Pass Pre-tensioner - Driver Pre-tensioner - Passenger Knee A/B - Driver Side A/B Driver Longitudinal Δv

In the pre-selected discrete values reported for the 18 tests, where data was reported, it correlated with the direct observations in all of the cases. In some of the cases, a “Phantom Driver” system was installed to perform the crash test.

In the cases where it was or was not buckled using the vehicle’s factory seatbelt, the CDR Tool reported that state correctly.

For the parameters that reported continuous, time-series values, all correlated very closely between the CDR data and the external data that was reported. In the case of the “Vehicle, Speed Indicated,” the pre-crash vehicle speeds were confirmed by a Racelogic VBOX and/or a timing gate, or both. The test vehicles were not equipped with onboard instrumentation capable of capturing engine RPM’s or accelerator pedal position. The engine RPM parameter was observed to be increasing or decreasing as expected.

The pedal position was reported in voltage or percentage.

Both parameter data points were confirmed by the operator. In the “Ignition Cycle” categories, two of the modules were imaged just prior to and immediately after the tests, and were incremented as expected.

Data Comparison of Discrete Values Parameter

CDR

Direct 17 18

Reported correctly 17 18

Reported Incorrectly 0 0

Brake Switch Status* Buckle Switch - Driver

17 18

Buckle Switch – Passenger Passenger Seat Occupied Driver Seat Position SIR/SRS MIL Status Cruise Control Shift Position* Frontal Airbag - driver Frontal Airbag - passenger Pretensioner - driver Pretensioner - passenger Knee Airbag - driver Side Airbag - driver

16 10 6 4 15 10 15 13 9 7 8 10

16 10 6 4 15 10 15 13 9 7 8 10

16 10 6 4 15 10 15 13 9 7 8 10

0 0 0 0 0 0 0 0 0 0 0 0

Side Airbag - passenger

5

5

5

0

Notes

Phantom Driver installed and buckled in some cases

includes roof rail data parameters where applicable

*includes PCM data reported for 2 tests

Table 2: Discrete Values are compared by category and number of tests in each parameter 90

Collision Magazine - Volume 9 Issue 1

www.collisionpublishing.com

EDR data retrieved using the CDR Tool was compared with reported data from external control instrumentation to examine the correlation of the reported data. Data parameters with discrete values as well as continuous, timeseries values were examined. Parameters that were reported as discrete values, such as “buckle switch position,” were verified by direct observations by the operator or other testing personnel. Parameters that reported as continuous or looped values, such as speed, were captured with external control instrumentation. That data was examined and compared against data retrieved by the CDR Tool.

All of the data retrieved by the CDR Tool in this limited study correlated well to the results from the other sources.

In terms of one context of “validation,” these tests illustrate the degree to which the data is an accurate representation of the real world events from the perspective of the intended use of the recorded and retrieved data. Moreover, in terms of specific quantifiable validation, as in an answer to the question “was the data valid?” this type of testing would seem to be useful toward answering that question.

I

ndividual Skills Your individual “qualifying training and experience” and how it might be used in some way to “confirm the data retrieved from the module” is “reliable,” but that it has been “verified,” starts with the idea that you’ve done everything in the imaging process in accordance with what you learned in a Technician Course and then evaluated the data as taught in the Analyst course. Couple that with your separate direct observation and a vehicle inspection together with comparison of CDR reported parameters and actual crash test data using an imaged pre-collision module for a baseline, witnessing the tests, and comparing the CDR report and control data from external instrumentation helps you better explain the various aspects of what

might be seen as “validation.” The annual ARC-CSI Crash Conference is an ideal model where one can be involved in such tests.

C

onclusion So if the question were posed: “how has the CDR been validated?” How would you respond?

The logical first thought is “what does the question mean or imply?” Which previously described aspect of “validation” is being contemplated in the question? Beyond that, with some of the information from this article, on should be able to address the various aspects of validation as they might be applied in the context of the CDR Tool and its application(s).

The module manufacturers, OEs and Bosch work closely together to ensure accurate data capture, recording, and translation. The data recorded in the module and then retrieved using the CDR Tool is a piece of a complete collision analysis and is correlated with the collision dynamics and physical evidence.

Overall “validation” can been done through actual crash testing with external control comparison instrumentation, along with direct observations, and then compared to the CDR Tool data and that data then reliably – but within limits – is an integral part of a solid collision analysis.

In the end, the “validation” of the method(s) of capturing and recording data in a module, the “validation” that Bosch Tool to retrieve the data such that the data was imaged/retrieved properly using the Bosch Tool and then the “validation” that the translation was done properly by the Tool are all supported by the comparison of observed or control data and that retrieved from a module.

Data Comparison of Continuous Values Parameter

CDR

Vehicle, Speed Indicated1 Accelerator Pedal Position Engine RPM1,2 Ignition Cycle @ Crash Ignition Cycle @ Investigation

18 13 9 2 2

External data 18 13 9 2 2

Reported correctly 17 13 9 2 2

Reported Incorrectly 1* 0 0 0 0

Notes

IIHS tests not included IIHS tests not included IIHS tests not included

*in 17 of the tests the CDR reported speed was within 1 mph of external data, 1 was 1.3 mph difference and was likely conversion and rounding variances between instruments 1 in 2 cases, vehicle speed and engine RPM's reported by PCM in addition to EDR 2 no external instrumentation but was increasing/decreasing as expected

Table 3: Data Comparison of Continuous Values www.collisionpublishing.com

Collision Magazine - Volume 9 Issue 1 91

I AM

CRASH INVESTIGATION It’s not like it looks on TV. Crash scene investigations are never cut and dry. Time is always of the essence.

No two scenes are alike, so I need my mapping equipment to be easy to run and versatile enough to handle any situation I’m up against.

We hear you.

Look into our TruPulse® 200X laser with TruAngle® and QuickMap 3D, an easy to operate and less expensive alternative to total stations.

Watch our recorded Crash Scene Mapping Webcast.

Request a quote or demonstration.

www.lasertech.com/collision 877.696.2584

Expert AutoStats®

S I MON

4N6XPRT BioMeknx™

Expert AutoStats® is a computer program containing over 42,000 vehicles cars, vans, utility vehicles, and light pickups. 1945-2012 model years are represented.

This program can be used alone or with our Expert Qwic Calcs® and Expert VIN DeCoder® programs. Also accessible from within REC-TEC.

(Lap top & D esktop W indow s 3 2 & 64 -bit O S C om p atible)

Enter:

M anufacturer and Year

Select:

M odel from pop-up window

Output:

Wheelbase Overall Length Height Wt. Distrib

Curb Weight Width Drive Wheels Front/Rear Track

M id-60's to present output also includes (when available): Front Overhang Rear Overhang Bumper Heights Hood Height Turning circle Wheel radius Bumper-to-Hood Bumper-to-Window

Expert AutoStats® is currently owned by over 700 private individuals and 300 Law Enforcement agencies in the U.S.A., Canada, and South America. Additional information, brochure, and order from can be downloaded from:

www.4n6xprt.com/4n6as.htm

4N6XPRT BioMeknx is designed as a collection of the Biomechanical data of importance to the Accident Investigator into one easily accessible reference location. It is designed as a program to be useful to ALL accident investigators, not just the Biomechanical expert.

The program includes: 1. Over 65 printable illustrations and charts 2. 10 Separate categories or sections of information related to forensic biomechanics 3. Information on walking speeds of people from 17 months to > 65 years 4. Calculation modules for: - segment length from total body height, - segment weights and Centers of M ass (CoM ) based on total body weight, - Predicted M aximum Walking Speed based on total height 5. Information was obtained by review of over 65 scientific texts, several of which are now "out of print"

www.4n6xprt.com/4n6bm.htm

PROGRAM ORDER FORM (Please Print)

SImulation MOdel Non-linear SIMON is a fully 3-dimensional dynamic simulation of the response of one or more vehicles to: • Driver Inputs (steering, braking, throttle, gear shift) • Collisions • Terrain Factors (irregular terrain, curbs, soft soil, slippery regions, hydroplaning, potholes, …)

• Aerodynamics (wind forces, airborne trajectory) SIMON was built using the latest advances in software and simulation technology, based on a new, 3-D vehicle dynamics engine developed by Engineering Dynamics Corporation.

Any number of vehicles may be included in a SIMON simulation. The user assigns initial positions and velocities for each vehicle. The user may also assign driver controls, wheel set-up conditions (tire blow-out, wheel damage, brake adjustment/failure, curb impact) and accelerometers. Using this information, SIMON calculates the forces acting on the vehicle and uses these forces to calculate vehicle position, velocity, acceleration and collision damage at user-specified time intervals. The results may be displayed numerically (in a spreadsheet format) or visually (in 3-D viewers).

SIMON has been validated against numerous well-instrumented vehicle handling studies, including combined steering and braking, severe irregular terrain traversal, rollover tests, staged crash tests and tire blow-out experiments. Program results easily meet Federal standards for the admissibility of scientific evidence.

VISUAL REALITY

Contact Name: ________________________________________________ Company: ____________________________________________________ Street: ______________________________________________________ City:____________________ State:____ Zip:__ __ Country: __________ Phone: (_____) _______________ Fax: (_____) ___________________ E-M ail: ______________________________________________________ Expert AutoStats® 4N6XPRT BioM eknx™ Expert Qwic Calcs® 4N6XPRT Ped & Bike Calcs® 4N6XPRT StifCalcs® Expert VIN DeCoder® (pkg) Expert TireStuf® Order Processing

- $ 625.00 ea.

- $ 495.00 ea.

- $ 275.00 ea.

- $ 375.00 ea.

- $ 650.00 ea.

- $ 550.00 ea.

- $ 85.00 ea.

= ________ = ________ = ________ = ________ = ________ = ________ = ________

- Check = $5.00 / Credit Card = $10.00 / G ovt. P.O . = $15.00 = _______ Notarized Affidavit Requirement $25.00 per required Notarized Signature = _______

Q Deliver via electronic download (Email address Required) Q Ship on USB - $35.00 per disk per program California Sales Tax Enclosed is:

- 8.50%

TOTAL (U.S. Dollars)

= 0.00 = ______

= ________

= ________

Visa ___ MasterCard ___ Am. Ex. ___ Exp ____/____ - Check ___ - Gvt PO ___

Card Number: Name on Card: Signature:

_______________________________________________ _______________________________________________ ________________________________________________

Please M ake Checks*/Purchase Orders Payable to:

4N6XPRT Systems®

8387 University Ave - La M esa, CA 91942-9342 - U.S.A. FAX: (619) 464-2206 Phone: (619) 464-3478 Web: http://www.4n6xprt.com C hecks * M U ST * be draw n on a U.S. bank. O rders are shipp ed within 10 working days of receipt.

Prices subject to cha ng e without notice.

M ultip le orders and Package discounts availab le. Please call for details.

2014 CDR summit DVD

C

2014 Vol.9 Iss.1

ollision C The International Compendium for Crash Research

Volume 9 Issue 1

SPRING 2014

Collision: The International Compendium for Crash Research

Validating CDR Data Through Crash Testing

Signs of a Wreck

Volume 9, Issue 1 - Spring 2014

How to Spot a Rolling Disaster and Testing and Simulation

3D Simulation of a Crash Test Series in SIMON Utilizing A, B, C and D Stiffness Coefficients

collisionmagazine.com

Analysis of Motorcycle and Rider Limits on a Curve

An Amazing

Speed Computation