Topology Optimization Of Front Leaf Spring Mounting Bracket
ISSN: 2455-2631 July 2018 IJSDR Volume 3, Issue 7Topology Optimization of Front Leaf SpringMounting BracketVijay Kalantre1, K. H. Munde2, Ashish Pawar31PGscholar, Mechanical Department, APCOER, Savitribai Phule Pune University, PuneProfessor, Mechanical Department, APCOER, Savitribai Phule Pune University, Pune2,3AssistantAbstract—Automotive industry is the largest growing &widely spread industry today. And the industry iscontinuing to strive for light weight vehicle in improvingfuel efficiency and emission reduction performance. Tooptimize cost and weight parameters, a correct approachof cost management in the product development processis necessary. This paper outlines the various methods oftopology optimization and reviewing the tool of topologyoptimization for the design & development of variousautomotive components. Using various techniques ofshape, size & topology optimization may subsystems ofautomobile can be designed for light weighting withoutcompromising strength of the components with increasein component compatibility. Paper also overviewsvarious areas in which topology optimization is usedsuccessfully to achieve significant weight loss andultimately increasing performance of automobile withconsiderable reduction in cost. Topology optimization ofLeaf Spring Mounting Bracket is performed here as acase study and which results in 19.39 % of weightreduction without compromising strength of the bracket.Topology is scientific tool that provides guideline aboutremoving of inefficient material from the structureIndex Terms—Ansys 16.0 & 18.0, BESO, EvolutionaryStructural Optimization (ESO), Shape Optimization,Size Optimization, Topology Optimization (TO)I.INTRODUCTIONIn the present tough international competition,automotive companies can only survive if they canprovide cost optimized, light-weighted, resourceefficient, and durable and stable products. At the sametime, the product must be introduced quickly into themarket. These demands can only be met ifstructural optimization tools are used in addition toestablished CAE, CAD, DMU and PDM systems.In this paper a suspension bracket (leaf springmounting bracket) of Mahindra Classic Jeep has beenanalyzed and topologically optimized to reduce itsweight but without compromising its strength. Modalanalysis is also carried out and it shows that theminimum natural frequency is much above the roadexcitation frequency range. That means condition ofresonance will be avoided and so as the maximumstress value will exceed the safe value anyway. All theanalysis and optimization is done in Ansys 19.0 asnow Ansys has introduced topology optimizationoption in version 18.0 and above. EvolutionaryIJSDR1807002Structural Optimization Method (ESO) is used here foroptimization.Structure topology optimization design is a ontheory, which can be divided into three categorySizing optimization, Shape optimization and materialselection, Topology optimization according to thestructural optimization model or optimize layers.Topology optimization is usually also known as theoptimization of the distribution (or layoutoptimization, shape optimization of a broad sense),and its importance is to find the best possible topologyor layout in given design objectives and constraints,usually has the most decisive factor in the efficiencyof the development of new products.The light weighting of vehicle is important objectiveof such topology optimization. There are threecommon approaches to minimize vehicle weight inpractice that are; substitution with light weightmaterial, downsizing of vehicle and removingunwanted material from the structural component.Solutions obtained by standard size and shapeoptimization methods keep the same topology of theinitial design. These solutions are often far fromoptimal because other competing topologies cannot beexplored. For this reason, topology optimizationmethods are becoming increasingly important aspotential tools in engineering design. THEORYGenerally, vehicle product development process canbe divided into four stages: 1) Conceptual designstage; 2) Detailed design stage; 3) Product shapingstage; 4) Structure improving design after batchproduction. Domestic and foreign scholars haveconducted extensive researches and applicationexploration, finally worked out the two key factors thatimpact of CAE about car body in conceptdevelopment: the rapid construction of the analysismodel requirements for different design plan and sizemodification; rapid achievement of various planscomparing in performance and structural designInternational Journal of Scientific Development and Research (IJSDR) www.ijsdr.org12
ISSN: 2455-2631optimization. (This aspect has been mature relativelyin technology due to the progress of structural analysismethod and the application of powerful analysissoftware). The fundamental differences betweentopology optimization and the traditional design, CAEanalysis design: Topology optimization separated thetrial production from structure analysis, avoided actualsample car production before the stereotypes of basicproducts, accordingly achieve both cost saving andimprovement of efficiency. Here the basics ofoptimization in general and topology optimization inparticular will be described. Mathematical optimizationThe basic principle of optimization is to find the bestpossible solution under given circumstances. Oneexample of optimization is finding the quickest routewhen using the public transportation system or, as inthe case of structural optimization, finding the optimaldistribution of material that satisfies some givenrequirements. This is most often done by decisionsmade by the passenger or the engineer from their ownexperience and knowledge about the subject. Theobjective of the optimization problem is often somesort of maximization or minimization, for exampleminimization of required time or maximization ofstiffness. To be able to find the optimum solution the goodness' of a solution depending on a particular setof design variables needs to be expressed with anumerical value. This is typically done with a functionof the design variables known as the cost function.Mathematically the general optimization problem ismost often formulated as minimization of the costfunction (which can easily be transformed tomaximization by minimizing the negative function)subject to constraints, this can be expressed as: July 2018 IJSDR Volume 3, Issue 7define the constraints of the problem. This is called aconstrained optimization problem. Structural optimizationStructural optimization is one application ofoptimization. Here the purpose is to find the optimalmaterial distribution according to some givendemands of a structure. Some common functions tominimize are the mass, displacement or thecompliance (strain energy). This problem is most oftensubject to some constraints, for example constraints onthe mass or on the size of the component. Thisoptimization is traditionally done manually using aniterative-intuitive process that roughly consists of thefollowing steps:1. A design is suggested2. The requirements of the design is evaluated, forexample by a finite element analysis (FEA)3. If the requirements are fulfilled, the optimizationprocess is finished. Else, modifications are made, anew improved design is proposed and step 2-3 arerepeated.The result depends heavily on the designer'sknowledge, experience and intuitive understanding ofthe problem. Changes to the design are made in anintuitive way, often using trial and error. This processcan be very time consuming and may result in asuboptimal design.The problem of structural optimization can,according to Christensen and Klarbring, be separatedin three different areas: sizing optimization, shapeoptimization and topology optimization see Figure 1. Sizing optimizationSizing optimization is the simplest form of structuraloptimization. The shape of the structure is known, andthe objective is to optimize the structure by adjustingsizes of the components. Here the design variables arethe sizes of the structural elements, for example thediameter of a rod or the thickness of a beam or a sheetmetal. See Figure (1.a) for an example of sizeoptimization where the diameter of the rods is thedesign variables.Where x is the vector of design parameters and f(x) isthe cost function. The functions gi(x) and hj(x) arecalled the inequality constraint function and theequality constraint function respectively and theyIJSDR1807002International Journal of Scientific Development and Research (IJSDR) www.ijsdr.org13
ISSN: 2455-2631 July 2018 IJSDR Volume 3, Issue 7Fig. 1: Different types of structuraloptimization Shape optimizationAs with sizing optimization the topology (number ofholes, beams, etc.) of the structure is already knownwhen using shape optimization, the shape optimizationwill not result in new holes or split bodies apart. Inshape optimization the design variables can forexample be thickness distribution along structuralmembers, diameter of holes, radii of fillets or any othermeasure. See Figure (1-b) for an example of shapeoptimization. A fundamental difference betweenshape vs. topology and size optimization is that insteadof having one or more design variable for each elementthe design variables in shape optimization each affectmany elements.II.LITERATURE SURVEY:Many research scholars have studied and proposedvarious methods of Topology Optimization foroptimizing different structural components ofautomobile since longer time. They have foundtopology as very effective and powerful tool forstructural optimization. The primary purpose of manyexperiments is found to be weight reduction.Mayur Jagatap and Ashvin Dhoke, two CAEengineers from TechMahindra have used AltairOptistruct as tool for design and optimize cast ironExhaust mounting bracket. Topologically Optimizeddesign was finalized based on manufacturingfeasibility and other practical constraint. They haveachieved 45% mass reduction and 50% of design cycletime and without compromising in strength and fatiguelife criteria. In future they are going to consider shapeoptimization for design. [1]Y. S. Kong, S. Abdullah, M. Z. Omar and S. M.Harisin their paper published in LAJSS (2016), haveIJSDR1807002optimized Automotive Spring Lower Seat usingtopological and topographical techniques. In theirwork 36.5% mass reduction and 27% complianceincrease was achieved. [2]Subhash Sudalaimuthu, Barry Lin, Mohd. Sithikand Rajiv Rajendramin their SAE InternationalPaper (2016) have explained process of designinglightweight track bar bracket right from the scratch.Design of Experiments (DOE) and topologyoptimization is used to decide bolt locations andcritical load path and followed shape optimization tofinalize the shape. [3]Suresh Kumar Kandreegula, Naveen Sukumar,Sunil Endugu and Umashanker Gupta published aSAE International paper in 2015 in which they haveprovided a forum to present new developments instructural Non-linear topology optimization. By thismethod structural optimization on irregular designdomains can be carried out easily. TransmissionHousing has been optimized using Non-linearTopology Optimization technique with the help ofSimulation tool Altair OptiStruct& verifiedexperimentally. They achieved cost reduction withoutsacrificing performance & safety. [4]Guan Zhou, Guangyao Li, Aiguo Cheng, andGuochun Wang,Hongmin Zhang and Yi Liao (2015SAE Paper) have done topology optimization on AutoBody for light weighting. They found weak part inBIW (Body in White) by applying Topologyoptimization and then performed sensitivity analysisto optimize thickness and significant weight reductionwas achieved. Density method of TopologyOptimization is used in this for Optimization. [5]In another SAEresearch article (2015), Bo Tan, YuYang, Jun Huang, Wenhui Liu, and DongqingZhanghave have done structural optimization ofHeavy Truck Propeller Shaft Bracket. Effect ofbracket structure mode on the frequency response andstress on it are studied. In this they combine finiteelement method and the multi-body dynamicstechnology to present NVH vibration improvement ofheavy truck drive shaft system. Topology optimizationtechnology provides support to the structureimprovement. [6]Guangiyo Li, Xiaudong Xu and colleagues havetopologically optimized an Automotive TailorWelded Blank(TWB) Door, tells their ASME paper in2015. Bidirectional Evolutionary OptimizationMethod (BESO) is extended here to optimize TWBInternational Journal of Scientific Development and Research (IJSDR) www.ijsdr.org14
ISSN: 2455-2631 July 2018 IJSDR Volume 3, Issue 7Door with multiple thicknesses then proposedoptimization method for TWBs. This method canprovide guide for light weight design for otherautomotive TWB components. [7]BGN Satya Prasad and M Anil Kumar managersfrom Hyundai Motor India Engineering presented apaper in Altair Technology Conference 2013 Indiaregarding Topology Optimization of Alloy Wheel.They used the technique of topology to design alightweight Aluminum wheel using Hypermesh andOptistruct. Mass reduction of 340 gm per wheel isachieved by them. [8]Parag Nemichand Jain and Satish Pavuluri fromAshok Leyland, Ltd. in 2013 published their work inSAE journal about Experimental and Finite ElementalAnalysis of Bogie Suspension Mounting Brackets.This analysis helped to create a methodology toanalyze bogie suspension brackets. [9]Brake Actuator Mounting Bracket was optimized in2010 by Vasudev Rao S. and Chetan Raval fromMahindra Engineering Services. This shows theirwork in HTC. Altair HyperWorksOptistruct was theiroptimization tool. Objective was to minimize totalstatic deflection of bracket. They achieved it withinreduced time. [10]Some literatures have reviewed various applications oftopology optimization in automotive applications [11]as well as use topology, shape & size optimization atvarious stages of design is also described [14].Tool of topology optimization is mainly used for massreduction in many structural applications like EngineMounting Bracket, Transmission Housing Bracket,Cabin Suspension Bracket, Air filter bracket, SteeringColumn Bracket, tooled transmission mount, andjounce bump bracket. [13], [15], [16].Topology Optimization is becoming more importantin structural design which also can solve multipleloading condition problems. Basic formulation of TOproblem can be found in SAE paper.Main Key Highlights from the literature survey areas follows: Main purpose of most of the researcherswas the weight reduction in individualcomponent. Along with weight reduction complianceminimization (i.e. stiffness increase) andnatural frequency maximization was alsothe important considerations. Shape, Size and topology optimizationsare used in combinations by manyresearchers to get most optimizedstructure.Density method and ESO methods aremore often used for the optimization.Altair Optistruct as most powerfulSoftware package is used.Presently Ansys 18.0 and above versionsare containing Topology OptimizationModule separately which is used in thispresent work.IJSDR1807002 III. TOPOLOGY OPTIMIZATION OF BRACKET:Flow of Topology Optimization:Fig. 3: Flow of Topology Optimization CAD Model Preparation:3-D CAD Model is prepared in CATIA V5 partmodeling. Leaf spring is attached to two brackets oneat front end and other at rear end. Both bracketsmodelled in the software as shown below.Fig. 4: Front End BracketInternational Journal of Scientific Development and Research (IJSDR) www.ijsdr.org15
ISSN: 2455-2631 July 2018 IJSDR Volume 3, Issue 7Fig. 7: Fixed SupportFig. 5: Rear End Bracket Finite Element Analysis (Original Model):Static StructuralFE Analysis is carried out in Ansys R19.0 Academic.It has special module for Topology Optimization.Only Front-End Bracket is optimized here. It iscarried out in following steps.A.Meshing:Ansys default meshing is used to mesh the model. Noany special mesh refining or special element type isused for meshing. Mesh statistics shows 11723number of nodes and 6285 number of elements.Fig. 8: Displacement Loading and Material:Material: Material assigned for bracket isStructural Steel which has followingproperties;Yield Strength Syt 250 MPaUltimate Tensile Strength 460 MPaYoung’s Modulus, E 210 GPaPoisson's ratio, ν 0.3 Load Calculations:Gross Vehicle Weight is 1600 kg. And with occupant& other material we can consider 500 kg extra.Therefore, total vehicle weight is 1600 500 2100 kgForceComingon1wheel 2100/4 525kg 525x9.81 5150.25 N (5200 N Approx.)This force will be transferred from suspension. Frontsuspension is leaf spring type and has two brackets oftwo ends. We will consider Front End Bracket forstatic topology optimization and modal optimizationfor weight reduction.Fig. 6: Mesh ModelB.Boundary Conditions: Supports & DisplacementIn this surface of mounting hole is fixed and thetranslation of upper surface made zero in the directionperpendicular to its surface (i.e. Z direction) and madefree in other two directions. Loading in Ansys:Load of 5200 N is given at the two holes in which boltof the leaf spring eye is supported as shown in figure9 below.Fig. 9: LoadingIJSDR1807002International Journal of Scientific Development and Research (IJSDR) www.ijsdr.org16
ISSN: 2455-2631 July 2018 IJSDR Volume 3, Issue 7C.Results:Total deformation, Equivalent stress and Safety factoris found out in the bracket.Least StressedArea showingscope formaterial removalFig. 10: Total Deformation, Equivalent StressFigure shows that minimum natural frequency oforiginal bracket is 1628.1 Hz which too far from roadexcitation natural frequency ranging from 0 to 20 Hz.Hence bracket is safe in dynamic loading also. Topology Optimization in Ansys:Figure 11 below is showing the design and nondesign area in Ansys. We can make any changes indesign area only. Non-design area is generally areawith boundary condition. Fig 12 is showing thesuggested topology by the software when objective ofcompliance minimization and mass reduction of 30%was given to it. We can see the area with removedmaterial. Suggested Optimization reduces mass ofbracket from 0.525 kg to 0.384 kg which around27% reduced.Fig. 11: Safety FactorTable No. 1: Static Structural Results of OriginalBracketSr.ParameterValueNo.1Total Deformation0.043 mm2Equivalent Stress60.774 MPa3Safety Factor Minimum4.11364Weight of the Bracket0.526 kgFactor of Safety is 4.1136 which is almost over safefor static loading. Hence there is scope foroptimization. Figure of Stress is showing the leaststressed area which is we can scope for materialremoval.D.Modal Analysis:Fig. 12: Modal Analysis of Original BracketIJSDR1807002Fig. 13: Design and Non-Design AreaFig. 14: Suggested topologyIV.BRACKET MODIFICATION AND RE-ANALYSIS:A. Following figure shows the modified form ofthe bracket.Fig. 15: Modified BracketInternational Journal of Scientific Development and Research (IJSDR) www.ijsdr.org17
ISSN: 2455-2631 July 2018 IJSDR Volume 3, Issue 7B. Analysis of Modified Bracket:All the mesh properties and boundary conditions keptunchanged and results simulated again. Followingfigures shows the analysis results.Fig. 18: Modal Analysis of Modified Bracket V.RESULT COMPARISON:Table No. 3: Result ComparisonFig. 16: Total Deformation, Equivalent Stress ofmodified tressSafety FactorMinimumWeightofBracket234Fig. 17: Safety Factor of Modified BracketTable No. 2: Static Structural Results of ModifiedBracketSr.ParameterValueNo.1Total Deformation0.048 mm2Equivalent Stress61.48 MPa3Safety Factor Minimum4.0664Weight of Bracket0.424 kgC. Modal Analysis of Modified BracketModal analysis of Modified bracket shows minimumnatural frequency of 1616.4 Hz means almost nocompromise with natural frequency. Means newbracket is also safe in dynamic loading.IJSDR1807002VI.Value forOriginalBracket0.043mm60.774MPa4.1136Value forModifiedBracket0.048 mmDifference(NewOriginal)0.005 mm61.48MPa4.0660.706 MPa0.526 kg0.424 kg-0.102 kg(19.39 %)-0.047CONCLUSIONFrom the comparison of the result it is concluded thattopology optimization is very effective tool foroptimization. In this case weight reduction of 19.39 %is observed almost without compromising strength andfactor of safety.REFERENCES[1] Mayur Jagtap, Ashvin Dhoke, “TopologyOptimization of Exhaust Mounting Bracket”,Tech Mahindra, Altair Technology ConferenceIndia, 2017.[2] Y.S. Kong, S. Abdullah, M.Z. Omar, S.M. Haris,“Topological and Topographical Optimization ofAutomotive Spring Lower Seat”, Latin AmericanJournal of Structures, 2016.[3] Subhash Sudulaimuthu, Barry Lin, MohamedSithik, Rajeev Rajendran, “Track Bar BracketDevelopment with the Help of AdvancedOptimization Techniques”, SAE Technical Paper2016-01-1387, Apr 2016.[4] Sureshkumar Kadrigulla, Navin Sukumar,“Structural Non-linear Topology Optimization ofTransmission Housing and Its ExperimentalVerification”, SAE Technical paper, 2015-01-International Journal of Scientific Development and Research (IJSDR) www.ijsdr.org18
ISSN: 2455-2631 July 2018 IJSDR Volume 3, Issue 70098, Mar 2015.[5] Guan Zhou, Guangyo Li, Aiguo Cheng,Guochaun Wang, Hongmin Zhang, and Yi Liao,“The Lightweight of Auto Body Basef onTopology Optimization & Sensitivity Analysis”,SAE Technical Paper, 2015-01-1367, Apr 2015.[6] Bo Tan, Yu Yang, Jun Huang, Wenhui Liu, andDongquing Zhang “Structure OptimizationMethod for Heavy Truck Propeller ShaftBracket”, SAE Technical paper, 2015-01-0638,Apr 2015.[7] Guangyao Li, Fengxiang Xu, Xiaodong Huang,and Guangyong Sun, “Topology Optimization ofan Automotive Tailor-Welded Blank Door”,Journal of Mechanical Design, ASME, Vol. 137/055001-1, May 2015.[8] BGN Satya Prasad, M Anil kumar, “TopologyOptimization of Alloy Wheel”, Hyundai,presented at Altair Technology Conference India,2013[9] Parag Nemichand Jain, Satish Pavulari,“Experiemental and Finite Elemnt Analysis ofBogie Suspension Mounting Brackets”, SAETechinical Paper, 2013-01-2789, Nov 2013.[10] Vasudeva Rao. S, Chetan Raval, “Brake ”, Mahindra Engineering, presentedat HTC 2010.[11] Shi Jin-fa, Sun Jian-hui, “Overview on Innovationof Topology Optimization in Vehicle CAE”InternationalConferenceonElectronicComputer Technology, IEEE, 2009.[12] Manoj Ukhande, Bharat Pawar, Girish Shegavi,“Control Arm Weight Optimization UsingHyperWorks”, Bharat Forge, presented at HTC2009.[13] Xiao-Yong Pan and Doni Zonni, Guo-ZhongChai, Yan-Qing Zhao and Cui-Cui Jiang,“Structural Optimization for Engine MountBracket”, SAE Technical Paper, 2007-01-2419,2007.[14] Hong Suk Chang, “A Study on the AnalysisMethod for Optimizing Mounting Brackets”,2006 SAE World Congress, Detroit, Michigan,2006-01-1480, Apr 3-6, 2006.[15] Yugi Ogata, Satoru Suzuki, Masami Hiraoka,“Development of Topology Optimization Methodfor reduction of Transmission Housing Weight”,SAE Technical Paper, 2005-01-1699, 2005.[16] Eduardo Castelo Branco Porto, Geraldo MinoruKato, Rogerio Ribeiro, Walter Wilhem LorenzJunior, “Structural Optimization of Rear CabinSuspension Mounting Bracket and of a Frame AirFilter Bracket”, SAE Technical Paper, 2004-013391, 2004.IJSDR1807002International Journal of Scientific Development and Research (IJSDR) www.ijsdr.org19
Structure topology optimization design is a complex multi-standard, multi-disciplinary optimization theory, which can be divided into three category Sizing optimization, Shape optimization and material selection, Topology optimization according to the structura
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1935-1940 Ford Car & 1935-1941 Ford Truck Rear Leaf Spring Parts Description Part#: 404-4610-00 #1 Leaf Spring mounting kit includes: U-bolts, leaf pads, 5-hole spring plates with lower shock mount and hardware #2 Leaf Springs: 48" center to center multi-leaf springs #3 Leaf Spring Shock kit: 3-hole upper shock mount (pair), shocks (pair) and .
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