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 | Page770
Scientistsandengineersarealwayslookingformorerigorousdecision makingprocesses,suchasoptimization,to keepupwiththerisingneedtoefficientlycutmanufacturingcostsinordertosurviveglobalcompetitiveness.Techniques for designing and manufacturing goods and systems that are both cost effective and efficient are extensive, with new optimization approaches still being researched. Finite element (FE) based design optimization is now a well established engineering design process. Continual improvements in software and computer speed have made the whole design process more adaptable, reducing the hundreds of hours traditionally devoted in an engineering design to a few, dependingonthetypeofstudy.Withthefastadvancementofcomputertechnology,thenumberofengineeringissuesthat maybesolvedutilisingoptimizationapproachescontinuestogrow.Optimizationtechniquesareusedinconjunctionwith contemporary computer aided design (CAD) tools to improve the process of conceptual analysis and detailed design of engineering systems. While there are a plethora of optimization techniques available, Only a few approaches are chosen andimplementedinFEandCADsoftwareoutofthemanymethodsandalgorithmsnowavailableandunderinvestigation. The current research focuses on demonstrating modern finite element software's optimization capabilities using a few engineering related examples of increasing complexity. ANSYS® 2021R1 was chosen as the analysis' baseline Finite Element software. Furthermore, the chosen information delivery technique is a simulation approach that provides a detailed explanation of the processes required to complete each of the optimization analyses. In comparison to earlier work,thecurrentstudytakesamoreillustratedanddescriptiveapproachtoengineeringoptimization.
o Topological and Parametric optimization modules areexplored. o Mechanical and Aerospace Engineering related optimizationcasesareconsidered. o Post processingisappliedtooptimizedresults.
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Abstract: In today's engineering world, optimization is critical. Advanced optimization techniques and algorithms are used in today's Finite Element and CAD Software to find efficient and cost effective solutions to difficult engineering challenges. For this work, the popular Finite Element programme ANSYS 2021R1 was used as the baseline optimization package. To evaluate the performance and capabilities of contemporary optimization software, a series of escalating complexity cases pertinent to the domains of Mechanical and Aerospace Engineering are selected and then optimised. In addition, for each of the study scenarios studied, a simulation style methodology is built with step by step definitions and recommendations for the optimization process.
Keywords: Ansys2021R1, optimization module, topology optimization module , finite element software , cad software.
Table1:Scopeofthestudy In Scope Out of Scope o Finite element optimization performed in FE softwareANSYS®2021R1.
o Simulation descriptionofoptimizationprocess.
o OptimizationusingadifferentFEorCADSoftware. o Other optimization methods or algorithms not specified.
TOPOLOGY OPTIMIZATION OF A HELICOPTER PITCH ARM Podugu Appalanarasayya*, M.Y.Prasada Rao** Department of Mechanical Engineering, MVGR College of Engineering, Vizianagaram, Andhra Pradesh, India
SCOPE AND OBJECTIVES
Additionally,anumberofassumptionsareconsideredforthisstudyincluding: o ThereaderhasasoundknowledgeorhasbeenpreviouslyexposedtoFiniteElementAnalysis(FEA)software andspecificallyANSYS®version2021R1.
o Optimization cases relevant to other fields or subjects. o Manufacturing analyses, mass production and otherpostprocessingmethods. o DescriptionofCADgenerationprocess.
*+**
1. INTRODUCTION
ThescopeofthisstudyisdetailedinTable1.
Previousliteratureassertsthatoptimizationtechniqueshavereachedasubstantialdegreeofmaturityinrecentyearsand arebeingimplementedinanever increasingspectrumofindustries.Athoroughpastliteratureanalysishasbeencarried outinordertocomprehendtheextentofthisprojectandthus,betterunderstandthetopicandpotentialadvantagesofthe outcomes. The review focuses on engineering optimization from the early concepts to modern techniques and methods employedglobally.Inaddition,theanalysisfocusesonoptimizationintheselectedbaselinesoftwareAnsys®2021R1and whatmilestoneshavebeencurrentlyreachedregardingthecapabilityandpotentialofthealgorithmsimplemented. AND EVOLUTION OF 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 | Page771 o ThereaderisfamiliarwithbasicMechanicaland/orAerospaceengineeringtopics,conceptsandapplicationsas wellasessentialoptimizationprinciples. 2. LITERATURE REVIEW
HISTORY
1687 newtonstudiesthebodyofminimalresistance.
19th Century 1806 legendrepresentstheleastsquaresmethodforoptimization.
1847 a.l.cauchypresentsthegradientmethod.
17th Century 1636 fermatshowsthatlighttravelsbetweentwopointsin minimaltime.
18th Century 1712 j.s.konigshowsthattheshapeofahoneycombisoptimal fortheapplication.
1754 lagrangeformulatestheproblemofminimalsurfaces.
1857 j.w.gibbsshowsthatchemicalequilibriumisanenergy minimum. 20th Century 1917 h.hancockpublishesthefirstbookonoptimization.
1917 d.w.thompsonappliesoptimizationtoanalysetheforms oflivingorganisms. 1947 g.dantzigpresentsthesimplexmethodforsolvinglinear programmingproblems.
1951 h.markowitzpresentshistheorybasedonquadratic optimization. 1954 optimalcontroltheorybeginstodevelop,andthespacerace givesadditionalboosttotheoptimizationfield.
1957 r.bellmanpresentstheoptimalityprinciple.
Table2:OptimizationEvolution Period Date Events Antiquity 300bc euclidconsidersminimumdistancebetweenapointanda line. 100bc heronpostulatesthatbeamsoflightalwaystaketheshortest path.
table3:classificationofoptimizationmethods classification optimizationtechnique newton’smethodandvariations lagrangianmethod least squaresmethod iterative (traditional)methods coordinatedescentmethod conjugategradientmethod steepestdescentmethod ellipsoid interpolationmethodandextrapolation simplex geneticdynamicevolutionarymemeticmethodalgorithmalgorithmsrelaxationalgorithms
OPTIMIZATION METHODS
algorithms(modern) particleswarmoptimization beecolonyoptimization simulatedannealingalgorithm stochasticalgorithms hillclimbing probabilisticalgorithmalgorithms
1980’s polynomialalgorithmsforoptimizationproblemsare developed. 1990’s computersbecomemoreefficientandalgorithmsforglobal optimizationaredeveloped(heuristic). 21st Century modernalgorithmsaredeveloped,andoptimizationsoftware rapidlygainspopularity.
Thereis nota soleoptimizationtechniqueavailablefor efficientlysolvingall engineeringproblems.therefore,a seriesof optimization techniques have been developed for solving different types of optimization cases. there is an increasing number of available optimization methods ranging from century old mathematical models to modern algorithms still under research. optimization techniques can be classified as mathematical programming or traditional techniques that involvetheapplicationofiterativemethodsandmodernalgorithmsthatarecurrentlybeingdevelopedandimproved. table3illustratesthemostcommonoptimizationtechniquesavailable.
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OPTIMIZATION AND ANSYS® FE based design optimization is currently a well recognized and influential practice for engineering design. The applicationofthistechniqueinvolvesseveralstagessuchasgeometricmodelling,meshgeneration,finiteelementmethod implementation, numerical optimization techniques and a number of post processing stages (A. Vaidya, 2005). Software enhancements have made the overall design process more versatile and reliable. Ansys® 2021R1 as the selected finite element software for this study, is one of the leading multi objective optimization software in engineering. Its improved userinterfaceofferseffectiveuser machinecommunicationwheretheengineeringintent,datarelationshipsandthestate oftheanalysiscanbeeffortlesslyunderstood.
DESIGNXPLORER™ MODULE
OPTIMIZATION MODULES
The main purpose of the DesignXplorer™ module is to effectively identify the relationship between the design variables and the desired performance of a model. Based on the output, the analyst can modify and influence the design, so the requiredoutcomesareobtained.DesignXplorer™providesenoughtoolstoperformparametricoptimizationcaseswitha reasonable number of parameters in a single or Multiphysics analysis. In other words, DesignXplorer is a powerful approachtoexplore,understand,andoptimizeanengineeringchallenge.Oncerun,theDesignXplorer™modulecomprises aseriesofstepstoobtainanoptimizedmodel.Assoonasthemodelisgenerated,andtheparametersordesignvariables areset,awhatifstudycanbecarriedout.
As previously mentioned, Ansys® 2021R1 implements two different optimization types. A parametric optimization analysiscanbecarriedoutfromtheDesignXplorer™moduleandaTopologicaloptimizationstudy,alsoaccessiblefromthe Workbenchplatform
TOPOLOGY OPTIMIZATION MODULE
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 | Page773
Themainobjectiveoftopologicaloptimizationistofindthebestpossibleuseofmaterialsforamodelthatis subjecttoa single or multiple load distributions. In other words, the maximum stiffness design is sought, so the minimum efficient material use is achieved. The topology optimization technology implemented in Ansys® Mechanical, provides the necessarytoolstodesignlightweightandefficientcomponentsforawiderangeofapplications.Ansys®2021R1 includes a directtopological optimization module inthe Workbenchinterface which greatly simplifies thesteps requiredto carry out an analysis. The standard procedure for topology optimization involves defining the model and creating a mesh, specifying optimized and non optimized regions, defining load cases and the optimization parameters (objective function/sandconstraints).Thestudyisthenrun,andtheresultscanbereviewedandpost processed.
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 | Page774 Figure3illustratesthestandardprocesscarriedoutinatopologyoptimizationanalysis. Figure3:TopologyOptimizationprocess(imagefromansys.com) PARAMETRIC OPTIMIZATION TECHNIQUES Once the model constraints and requirements are defined and the simulation’s responses are characterized, designxplorer™providesthefollowingtypesofoptimizationalgorithms: 1.Shiftedhammersleysampling 2. Multi objectivegeneticalgorithm(moga). 3.Nonlinearprogrammingbyquadraticlagrangian. 4.Adaptivesingleandmulti objectiveoptimization. OTHER OPTIMIZATION SOFTWARE Whilethereisplentyofcommercialnumerical(mathematical)optimizationsoftwareavailable,afewCADorFEAprograms implementoptimizationaspartofanengineeringanalysis. Mathematicaloptimizationsoftwareofferssimplesolutionsto user definesfunctions,constraints,andvariablesinatheoreticalmanner,andinamodernprogramminglanguage.Inother words,anoptimizationprocedureiscarriedoutforanexplicitmathematicalfunction,generallyfordataanalysispurposes (Chang,2015)Popularsoftwareinthiscategoryinclude: o ALGLIB o GNUmodules o NMath o OptaPlanner o Python(SciPyModule)
3. OVERVIEWMethodologyOFSTUDY CASES
2. SIMULATION
Theaimistooptimizetheproposedshapeandruncalculationtoverifytheoptimizedshapemeetstheexpectation.
3. AGENDA Topology optimizationofpitcharmofahelicopterrotorhead.
1. OPTIMIZATION CASES
the simulation methodology aims to deliver the content in a more descriptive and illustrative manner. the optimization processforeachofthepreviouslymentionedcasesisdescribedinastepbystepbasiswithrelevantimagestosupportthe progress.for most study cases, the simulation begins with the fe analyses followed by the optimization phase assuming thattheinitialgeometryhasbeenalreadycreatedorimportedfromacad software.additionally,thissimulation assumes the reader has a sound knowledge of the finite element method and has been previously introduced to fea and optimizationsoftwaresuchasansys®
ThecasesconsideredcompriseastandardPitcharmofahelicopterrotorhead.Theoptimizationmethodandparameters tobeoptimizeddependoneachindividualcaseanditsoperationalrequirements.
4. INTRODUCTION TO PITCH ARM
The case selection process involved a comprehensive literature review to obtain a clearer idea of what optimization methods and cases have been considered in previous studies as well as which optimization software and algorithms are implemented. The selected cases involve a wide range of Mechanical and Aerospace related areas such as structural and fracture mechanics, materials science (standard and composites), computational fluid dynamics (CFD) heat transfer, and others.Suchstudies,alongwithappropriateoptimizationmethods,arethebaselinecriterionfortestingtheoptimization capabilities of the modern Finite Element software ANSYS® and its current potential for solving complex engineering problems.
Definitionandcalculationofthetopologyoptimization TransferbacktoCADusingcrosssectionextractionandskinsurfaces. Validationcalculationandcomparisonwiththeoriginalstructure
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 | Page775 Table4:CADandFEOptimizationSoftware CADSoftware FEASoftware o Catia™ o Autodesk Inventor (default CAD softwareforthisstudy) o Pro/Engineer o SolidWorks® o Abaqus® o FEMTools o Genesis o Odessy o PareTO o TopOpt
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 | Page776 5. OPTIMIZATION Optimizationofapitcharmofahelicopterrotorhead. 6. PITCH ARM DESCRIPTION OF THE TASK CoordinateSystem Usethesespecificationstocreateabetterdesign. Theinitialideatoreduceweightbycreatingthedeepeningintheyellowregionisnotthebestidea. Createabetterdesignintheyellowregion(theotherregionsshouldbekept),that.
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 | Page777 o Hasaboutthesamemassasthisoriginalmodel. o Ismuchstifferwithrespecttotheloadcasescenario. o Doesnotexceed200Mpa o Wherememberswillnotbelessthan12mm. o Willbymanufacturedwithpowderbedfusion. 7. RESULT OF THE ORIGINAL PITCH ARM
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 | Page778 8. GEOMETRY PREPARATION 9. 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 | Page779 Minmembersize=20mm Remainingvolume 50%ofthedesignspace Maximumstress 200MPa 10. SMOOTHING RESULTS Selectallthreebodiesforexport Generatesmoothingobjecttoexportinavalidationsystem. 11. VALIDATION CALCULATION AND COMPARISON WITH THE ORIGINAL STRUCTURE
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 | Page780 RightclickontheresultscellD7andtransfertodesignvalidationsystem UpdatecellD7 DisplaythepropertiesofmodelcellE3andcheckthesmoothedmodeltobetransferred(item20) RightclickonmodelcellE3andEdit. Carefullychecktheexistingobjectsinthetreeandmakeanyadjustmentifnecessary. Especially,checkexistingcoordinatesystem. Specifymeshsetting,useglobalaswellaslocalmeshsetting. Standardmechanicalqualityisrecommended.
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 | Page781 Defineanappropriatebodysizingforallbodies(e.g.,elementsize:3mm) Patchindependentmethodisrecommendedforallbodies:usedefeaturingandrefinementsettings. Stressoriginal:
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4. CONCLUSIONS
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