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Finite Element Modeling and Analysis ofFinite Element Modeling and Analysis ofNASCAR FrameNASCAR Frame

Brock SmithBrock SmithRyanRyan WibleWible

ME 450 COMP UTER ME 450 COMP UTER -- AI DED ENGIN EERIN G ANALY SISAI DED ENGIN EERIN G ANALY SIS

Spring 2003Spring 2003Instructor: Dr. H.U. AkayInstructor: Dr. H.U. Akay

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IntroductionIntroduction

uu National Association for Stock CarNational Association for Stock CarAuto Racing was Created FebruaryAuto Racing was Created February21, 194821, 1948

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Introduction ContinuedIntroduction Continued

uu With the use of computer aidedWith the use of computer aidedanalysis NASCAR Teams Can Save:analysis NASCAR Teams Can Save:

-- TimeTime-- MoneyMoney

-- LivesLives

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Related WorksRelated Works

uu Effects of Angles and Offsets in CrashEffects of Angles and Offsets in CrashSimulations of Automobiles withSimulations of Automobiles withLight TrucksLight Trucks

uu Design of a Winston Cup Chassis forDesign of a Winston Cup Chassis forTorsional StiffnessTorsional Stiffness

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EquationsEquations

uu F=maF=ma

uu a=Va=V22

/ / ??

uu F=aVF=aV 22

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BackgroundBackground

uu Why does NASCAR have rules?Why does NASCAR have rules?

-- Ensure Fair CompetitionEnsure Fair Competition

-- Driver SafetyDriver Safety

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BackgroundBackground

uu NASCAR Chassis RulesNASCAR Chassis Rules-- A minimum weight of 3,400 lbsA minimum weight of 3,400 lbs-- Frame rails are 3 inches wide by 4Frame rails are 3 inches wide by 4inches high with 1/8 inch wall thicknessinches high with 1/8 inch wall thicknessmade of magnetic steel box tubingmade of magnetic steel box tubing-- Frame rails minimum length of 65 inches,Frame rails minimum length of 65 inches,

must be parallel with minimum distancemust be parallel with minimum distancebetween of 50 inchesbetween of 50 inches

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NASCAR Chassis Rules ContinuedNASCAR Chassis Rules Continued

uu 110 inch wheel base, minimum roof height110 inch wheel base, minimum roof heightof 51 inchesof 51 inches

uu Firewall is 22Firewall is 22 -- gauge steelgauge steeluu The rear subframe must maintain aThe rear subframe must maintain a

minimum width of 37 inches at fuel cellminimum width of 37 inches at fuel cellmounting locationmounting location

uu Frame rails must be minimum of 29 inchesFrame rails must be minimum of 29 inchesat steering box and not exceed insideat steering box and not exceed insidewidth of 34 inches at the engine blockwidth of 34 inches at the engine block

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Model DetailsModel Details

uu Approximately 114 KeypointsApproximately 114 Keypoints

uu 169 Lines Connect the Keypoints169 Lines Connect the Keypoints

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Model DetailsModel Details

uu Two Element Types UsedTwo Element Types Used

1. BEAM41. BEAM4-- 33 -- D Elastic BeamD Elastic Beam

2. PIPE162. PIPE16-- Straight PipeStraight Pipe

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Model DetailsModel Details

uu After Entering AllAfter Entering AllKeypointsKeypoints

uu Connect AllConnect AllKeypoints withKeypoints withLinesLines

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Model DetailsModel Details

uu Enter the elementEnter the elementedge lengthedge length

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Model DetailsModel Details

uu Mesh ModelMesh Model

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Model DetailsModel Details

uu At keypoints 1 and 22 the chassis isAt keypoints 1 and 22 the chassis isconstrained in the X, Y, and Zconstrained in the X, Y, and Zdirections.directions.

uu At keypoints 7 and 16 the chassis isAt keypoints 7 and 16 the chassis isconstrained in the Y and Z directionsconstrained in the Y and Z directions

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Boundary ConditionsBoundary Conditions

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Static AnalysisStatic Analysis

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Static AnalysisStatic Analysis

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Bending StressBending Stress

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Von MisesVon Mises

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Dynamic AnalysisDynamic Analysisuu Dynamic analysis is theDynamic analysis is the

modeling of continuallymodeling of continuallychanging forces on thechanging forces on theframe as it goes fromframe as it goes fromstraightaway to curve.straightaway to curve.

uu Using the equationsUsing the equationsmentioned before, wementioned before, wecalculated the forces actingcalculated the forces actingon the chassis before andon the chassis before andin a curve.in a curve.

uu The Forces were in theThe Forces were in thenegative ynegative y -- directiondirection(downforce) and in the(downforce) and in thepositive zpositive z -- directiondirection(normal acceleration).(normal acceleration).

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Dynamic AnalysisDynamic Analysis

uu The graph showsThe graph showsthe ythe y -- displacementdisplacementwith respect towith respect to

time during thetime during thetransient analysis.transient analysis.uu It is easy to seeIt is easy to see

the effects of the effects of damping in thisdamping in thisplot.plot.

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Dynamic AnalysisDynamic Analysisuu The graph showsThe graph shows

zz-- displacement anddisplacement andis very similar tois very similar tothe ythe y -- displacementdisplacementgraph.graph.

uu Much like the yMuch like the y --displacement, it isdisplacement, it iseasy to see theeasy to see theeffects dampingeffects dampinghas on thehas on thetransient response.transient response.

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Von Mises StressVon Mises Stressuu The contour plot of The contour plot of

the Von Mises stressesthe Von Mises stressesis shown below.is shown below.

uu The maximum VonThe maximum Von

Mises stress wasMises stress wascalculated to becalculated to be174266 lb/in174266 lb/in 22 ..

uu The maximum stressThe maximum stresswas located at thewas located at thepoint where the y andpoint where the y andz forces meet at thez forces meet at thesame node.same node.

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ConclusionsConclusions

uu The current design of the NASCARThe current design of the NASCARchassis is very dependable during achassis is very dependable during arace and in crash situationsrace and in crash situations

uu The only problem is the extraThe only problem is the extrabending happening at the front of bending happening at the front of the frame.the frame.

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Impact StatementImpact Statement

uu Finite Element Analysis of NASCARFinite Element Analysis of NASCARchassis can be used to improvechassis can be used to improvedriver safety during a race.driver safety during a race.

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BibliographyBibliographyuu Burt, William.Burt, William. Stock Car Race Shop: Design andStock Car Race Shop: Design and

Construction of a NASCAR Stock CarConstruction of a NASCAR Stock Car . MBI. MBIPublishing, 2001. Osceola, WI.Publishing, 2001. Osceola, WI.

u SAE TECHN I CAL P AP ER SERI ES: 98305 3

Design of a Winston Cup Chassisfor Torsional StiffnessLonny L. Thompson, Srikanth Raju and E.HarryLaw

Department of Mechanical Engineering, ClemsonUniv.