A brake is a mechanical device that inhibits motion by absorbingenergyfromamovingsystem.Itisusedtoslowor stopamovingvehicleortopreventitsmotion,mostoften accomplished by friction. It is an energy converting mechanismthatconvertsavehicle'skineticenergyintoheat while stopping the rotation of the wheels. All braking systemsaredesignedtoreducethespeedandstopavehicle. Frictionconvertsthekineticenergyintoheat.Thegreater thepressureappliedtotheobject’ssurface,themorefriction &heatisproduced,&thesoonerthevehiclewillbebrought torest.Kineticfrictionactsinthebrakesandstaticfriction acts between the tire and road to slow down the vehicle. Most brakes commonly use friction between two surfaces pressedtogethertoconvertthekineticenergyofthemoving objectintoheat,thoughothermethodsofenergyconversion may be employed. For example, regenerative braking convertsmuchoftheenergytoelectricalenergy,whichmay bestoredforlateruse.Othermethodsconvertkineticenergy intopotentialenergyinsuchstoredformsaspressurizedair orpressurizedoil.Eddycurrentbrakesusemagneticfields toconvertkineticenergyintoelectriccurrentinthebrake disc,fin,orrail,whichisconvertedintoheat.
Themainobjectiveofouranalysisistocomparetheresults oftheinitialandfinaldesignofthebrakediscthroughfinite elementanalysisonAnsyssoftwareandverifythereduction in weight of the disc after optimizing it with the help of a topologyoptimizationtool.Thematerialselectedforanalysis isSS410whichissuitableforvariousparametersofthebrake
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 08 Issue: 12 | Dec 2021 www.irjet.net p ISSN: 2395 0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1256 Design, Analysis and Optimization of a Brake Disc for 4WD All-Terrain Vehicle Ranjeet Machale1, Tejas Tale2, Ashish Patil33, Atharv Kulkarni4 1 4Team Resonance Racing, AISSMS COE, Pune, Maharashtra, India. *** Abstract Disc brake system is one of the most advanced braking systems with the highest braking efficiency. It results in successfully stopping the vehicle at the minimum distance possible thereby increasing safety and performance. The Kinetic energy of the vehicle is converted into thermal energy due to the friction between the brake pads and the disc. Thus the brake disc becomes one of the most critical components of a disc brake system. Hence it is important to ensure its durability and performance using advanced computer aided analysis tools. This research paper includes the designing of brake discs for a 4WD All Terrain Vehicle and optimizing the design using analysis software such as ANSYS and Solidworks to majorly reduce weight while keeping the strength and temperature control at optimum level. Key Words: Brake disc, 4WD, SAE Baja, Inboard brakes, weightreduction,andtopologyoptimization.
1.1 Disc Brakes
Itwasn'tuntil 1955thata mass productioncarcamewith disc brakes.The1955CitroënDScamewith inboardfront disc brakes. In the years that followed, disc brakes would becomethenormonthefrontaxleofroadcars. Wenowhavevarioustypesofdiscbrakeswiththemost common type being the conventional cast iron disc setup. Cheaptoproduce,andmorethanadequateforyouraverage commuter, the cast iron disc brake dominates the market. Butwhathappenstocastironbrakeswhenabused,sayfor example,whenusedonsportscars?Castirondiscbrakescan suffer from 'brake fade' when used repeatedly and under high speedconditions.Thisphenomenoncomesinvarious formsandpresentsitselfasareductioninstoppingpower (mechanical fade) or a 'long' brake pedal (fluid fade). Mechanicalfadeiswhenthetemperaturesgetsohigh,thata layerofgascanbuildupbetweenthediscandpad,reducing stopping power. Fluid fade is when the same high temperaturefindsitswaytothebrakefluidwhichcanboil. This changes the properties of the fluid meaning that the brake pedal can go to the floor, reducing braking performance.
1. INTRODUCTION
TopologyOptimizationisusedtooptimizethedistribution ofmaterialwithinthedesiredboundaryknownasthedesign space for a given set of load cases to maximize the performancealongwithminimizingthemassthusreducing thecostformanufacturing.Topologyoptimizationutilizesa 3D design space and removes away material within it to achievethemostefficientdesign.Themethoddoesn'tcare aboutaesthetics,traditionalapproaches,oranyotherofthe usual design constraints that are normally used in the design. In conclusion, if we define the loading and the constraintsystem,itwillfigureoutthematerialneededto developthatloadpath.
Thediscbrakewasfirstpatentedin1902byLanchester Cars, however, it used copper brake pads which wore too quickly, and wasn't very practical. Various versions and adaptationswereuseduntiladiscbrakethatresembleswhat weseenow courtesyofJaguarwiththeirC typeracecar was introduced in the ‘50s Jaguar first showcased the advantages of their disc brakes at Le Mans in 1953. The reductioninfadeduetotheopen discdesignmeantthatthe carscouldbrakelaterandharderthandrum equippedrivals.
2. OBJECTIVES
1.2 Topology Optimization
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 08 Issue: 12 | Dec 2021 www.irjet.net p ISSN: 2395 0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1257 discsuchasdiscdiameter,Pattern&Materialcomposition. Thestaticstructuralandthermalanalysiswillbeconducted onbothinitialandoptimizeddesignstoevaluatetheresults. 3. MATERIAL SELECTION WehaveselectedstainlesssteelAISI410forourdesign. This material was selected considering the structural requirements, availability, machinability, and cost. Also, chromiumcontentinthematerialhelpswithbetterthermal conductivity and is less prone to rusting at high temperatures.ThepropertiesofSS410areasfollows: Table 1: materialproperties. Parameters Value Density 7750kg/m³ Meltingpoint 1480 1530°C Specificheatcapacity 460J/kg·K20°C Young’smodulus 190 210Gpa Thermalconductivity 24.9W/m·Kat100°C 4. DESIGN METHODOLOGYChart1 :Singlesamplingplan 5. CALCULATIONSTable2: Prerequisitesforcalculations VehicleWeight(withdriver=60) 250kg HeightofCG 22.50inch Wheelbase 58inch TireRadius 0.29m Pedalratio 6:01 PedalForce 350N µ(rotorandpad) 0.35 µ(tireandgravel) 0.7 TMCDiameter mm 20.64 ForceinTMC 2100N AreaofTMC 334.59mm^2 CalliperPistonArea 635.26mm^2 PadArea 2inch^2 PadLength 67.6mm PadBreadth 25.4mm Deceleration 0.9g WeightDistribution 47:53:00 StaticWeight 1 Front=(VehicleWeight*47/100) 117.5kg 2.Rear=(VehicleWeight*53/100) 132.5kg WeightTransfer WeightTransfer=VehicleWeight*Deceleration*(Heightof CG/Wheelbase)=87.28448276kg DynamicWeight 1.Front=StaticWeight+WeightTransfer 204.7844828kg 2.Rear=StaticWeight+WeightTransfer 45.21551724kg AxleLoad 1.Front=(Dynamicweight)*(9.81) 2008.935776N 2.Rear=(Dynamicweight)*(9.81) 443.5642241N Torqueonthewheels 1.Front=(Frontaxleload/2)*(TireRadius) 293.4050701 2.(Nm)Rear=(Rearaxleload/2)*(TireRadius) 64.78255494 Force(Nm)onTMC 1925(N) PressuregeneratedinTMC 5.75(N/mm2)
Aftertheanalysis,weproceedwithtopologyoptimizationby combining both the factor of safety and the thermal load cases.IterativeAnalysisandOptimizationwerecarriedout togetanoptimumresult.TopologyOptimizationwascarried outinthesamesoftwareasbeforei.e.Ansys19.2.Topology Optimizationhas a rangeof results,wewill betakingthat resultwhichsuitsourresultforfurtheranalysis.Targeted weightreductionwasatleast35%ofthetotalmassofthe disc Thefigurebelowshowsoneofthesolutionsfromthe rangeoftopologyoptimization.
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 08 Issue: 12 | Dec 2021 www.irjet.net p ISSN: 2395 0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1258 Forceinthecircuit 1.Front=5600.689(N) 2.Rear=2559.47(N) Pressuregeneratedinthecircuit 1.Front=4.405(N/mm2) 2.Rear=2.013(N/mm2) Kineticenergy(absorbedbythedisc) 8109.133(J) 6. INITIAL CAD DESIGN Fig 1:CADmodeloftheinitialdisc 7. FEA ANALYSIS 7.1 InitialFiganalysis2 :Equivalentstressofinitialdisc. Fig 3:Temperaturedistribution. Fig 4:Factorofsafetyfortheinitialdisc. 7.2 Topology Optimization
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 08 Issue: 12 | Dec 2021 www.irjet.net p ISSN: 2395 0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1259 Fig 5:Topologyoptimization. Hence by observing the removable area of the disc a new designwascreatedandanalyzedinAnsys19.2forvalidation ofpreviousresults 7.3 Optimized brake disc Fig 6:CADmodelofinitialdisc Fig 7:Equivalentstressoffinaldisc Fig 8:Temperaturedistribution Fig 9:Factorofsafetyforthefinaldisc. 8. RESULTS Table 3: resulttable. Parameters Beforeoptimization Afteroptimization mMinimu Maximum Minimum Maximum Mass(g) 761 493.18 stress(MPa)Equivalent 0.051 61.558 0.046 51.104 Total ndeformatio(mm) 0 0.0599 0 0.0158 Factor of safety 4.0612 4.892 Temp.°C 95.6 100 92 100
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 08 Issue: 12 | Dec 2021 www.irjet.net p ISSN: 2395 0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1260 9. CONCLUSION It is evident that there was a significant reduction in the weight of the brake disc of about 35%. It is also observed thatstressanddeformationwerereducedintheoptimized design. Also increased surface area due to the addition of slotsinthecontactpatchhasledtobetterheatdissipation andlowerdisctemperature. REFERENCES [1] FredPuhn,DiscBrakes,InBrakeHandbook,2ndEdition. Tucson,USA:HPBooks,1985,pp.23. [2] RudolfLimpert,ThermalAnalysisofFrictionBrakes,In BrakeDesignandSafety,3rdEdition,Warrendale,PA, USA,SAEInternational,2011,pp.65 67. [3] Sudin, M.N. Musthafah Mohd Tahir, Faiz Redza Ramli, ShamsulAnuarShamsuddin.“TopologyOptimizationin Automotive Brake Pedal Redesign”. International Journal of Engineering and Technology (IJET). 6. 398 402.Vol 6,2014,pp398 402. [4] “ANSYSMechanicalAPDLforFiniteElementAnalysis” Book by John M. Thompson and Mary Kathryn Thompson [5] “Finite Element Simulations with ANSYS Workbench 2019”PublishedJuly2,2019,ByHuei HuangLee BIOGRAPHIES Ranjeet MechanicalGraduateAtharvMechanicalGraduateAshishMechanicalGraduateTejasMechanicalGraduateMachale,Student,EngineerTaleStudent,Engineer.Patil,Student,EngineerKulkarni,Student,Engineer.2nd 4th Author Photo 3rd Author Photo
