Redesign of Lotus Europa Redesign of Lotus Europa Front SuspensionFront Suspension

ME 450: Finite Element AnalysisME 450: Finite Element AnalysisSpring 2007Spring 2007

Presented by: Presented by: Bart Sudhoff, Zachary Lightner, Jim Bart Sudhoff, Zachary Lightner, Jim

Milligan, Brian Schludecker, David GilesMilligan, Brian Schludecker, David Giles

Dr. NemaDr. Nema4/30/20074/30/2007

Summary & IntroductionSummary & IntroductionRedesign Front Suspension Upper Control Redesign Front Suspension Upper Control

ArmArmTop Speed Increase: 120 to 200 MPHTop Speed Increase: 120 to 200 MPHDesign Issues:Design Issues:

New weight of car due to increased engine New weight of car due to increased engine sizesize

New handling characteristicsNew handling characteristics

Original DesignOriginal Design Built in 1970Built in 1970 1470cc OHV 4 1470cc OHV 4

Cylinder Engine – Cylinder Engine – 78HP78HP

Front Wheel DriveFront Wheel Drive 4-Speed 4-Speed

TransmissionTransmission Curb Weight: 1320-Curb Weight: 1320-

1570lbs1570lbs Top Speed 120 MPHTop Speed 120 MPH

New DesignNew DesignEngine: Lexus V8 4.0L Quad CamEngine: Lexus V8 4.0L Quad CamTransmission: Porsche 5-SpeedTransmission: Porsche 5-SpeedSuspension: New Design of Lower/Upper Suspension: New Design of Lower/Upper

Control Arms, Springs, ShocksControl Arms, Springs, ShocksFactor of Safety of 5Factor of Safety of 5Light WeightLight WeightMinimal DeformationMinimal Deformation

Theoretical BackgroundTheoretical Background Decomposition of Decomposition of

model into stiffness, model into stiffness, force matricesforce matrices

Solution in form of Solution in form of nodal displacement nodal displacement matrixmatrix

4-node tetrahedral 4-node tetrahedral element element displacement displacement solutionsolution

Model DetailsModel DetailsUpper and Lower Control arms modeled Upper and Lower Control arms modeled

using Pro/Eusing Pro/EConstraintsConstraints

Fix – about the mounting holesFix – about the mounting holesForces applied at ball jointForces applied at ball joint

Model DetailsModel Details

Model DetailsModel Details

Load Case: X Y Z

Vertical Bump 0g  3g 0g 

Rebound 0g  2g 0g 

Pothole 0g  4g 1.5g

Force (N)

Load Case: X Y Z

Vertical Bump 0 -1024.5  -3166.3

Rebound 0 683 2110.9 

Pothole -4221.8 -1366 -768.3

Model DetailsModel Details

ResultsResults2” thick arm2” thick arm

Stress - 20.06 MPa Stress - 20.06 MPa Deformation - .102 mm Deformation - .102 mm Safety Factor – Greater than 10Safety Factor – Greater than 10

ResultsResults1.75” thick arm1.75” thick arm

Stress - 25.1 MPa Stress - 25.1 MPa Deformation - .128 mm Deformation - .128 mm Safety Factor – Greater than 5Safety Factor – Greater than 5

ResultsResults1.75” thick arm with relief1.75” thick arm with relief

Stress - 18.9 MPa. Stress - 18.9 MPa. Deformation - .131 mm Deformation - .131 mm Safety Factor – Greater than 5Safety Factor – Greater than 5

ResultsResults1.5” thick arm with relief1.5” thick arm with relief

Stress - 24.4 MPa Stress - 24.4 MPa Deformation - .184 mm Deformation - .184 mm Safety Factor – Greater than 5Safety Factor – Greater than 5

ResultsResults1.5” thick arm with relief1.5” thick arm with relief

Vertical BumpVertical BumpStress - 3.82 MPa Stress - 3.82 MPa Deformation - .0229mm Deformation - .0229mm Safety Factor – Greater than 10Safety Factor – Greater than 10

ReboundReboundStress - 14 MPaStress - 14 MPaDeformation - .106mm. Deformation - .106mm. Safety Factor – Greater than 10Safety Factor – Greater than 10

ConclusionConclusionChose 1 ½” control arm with relief cutsChose 1 ½” control arm with relief cutsPassed factor of safety testsPassed factor of safety testshas allowable deformationhas allowable deformationWill allow car to go 200 mphWill allow car to go 200 mph