Neil Barnes

1
ME 450 Analysis of Suspension Rocker and
Redesign

• Presented By
• Neil Barnes
• Nick Hatcher
• Kevin Feeley
• Andrew Taylor

2
Objectives

• To redesign the front suspension rocker for the
  4 Delphi Panther Racing Indycar.
• To reduce weight of front rockers by ½ a pound
  each.
• Constructed using Aluminum rather than Steel.

3
Introduction

• Rocker used in front suspension for Indy Racing
  League
• Maximum Load 7000 lbs
• Verified by DAG team at Panther Racing
• Constructed rocker in Pro-engineer
• Analyzed in ANSYS Workbench
• Analyzed stresses on steel rocker
• Resigned rocker in order to minimize stresses
• Constructed rocker from Aluminum

4
Front Suspension Rocker
Area of Interest
5
Theoretical Background

• Centrifugal
• Force

6
Theoretical Background

• Solid 92 (Tetrahedral Solid)
• 10 Nodes, 3-D Space
• DOF UX, UY, UZ
• WORKBENCH default element

7
Theoretical Background

• Local equation of Force
• f Ku
• Local equation (expanded 2D)
• Transformation Matrix

8
Theoretical Background

• Finding Global Stiffness Matrix (Moaveni)
• Global Equation (expanded 2D)
• Stress-Displacement Relationship

9
Theoretical Background

• Stress-Strain Relationship

10
Model Details

• Pro-Engineer Solid Models
• Converted to SAT format for ANSYS Workbench

4.5213.099 mm
R5.0001.350 mm
R5.0002.000 mm
11
Model Details

• Fine Mesh
• 47,039 Nodes
• 24,657 Elements

12
Boundary Conditions

• Fixed Support
• Zero Displacement
• Rotational Motion
• Only
• Force of 7000 lb
• Directed Outward

13
Results and Discussion

• Original Rocker
• Steel
• Maximum Stress
• 88.4 ksi
• Both sides of
• hoop

14
Results and Discussion

• Modified Rocker
• Aluminum
• Increased Radius of hole by 1.35 mm
• Increased Outside Radius by 2 mm
• Reduced Stress
• 79.28 ksi

15
Results and Discussion

• Further Modified Rocker
• Aluminum
• Increased Thickness by 3.099 mm
• Reduced Stress
• 65.05 ksi

16
Impact Statement

• Redesigning the front suspension rocker has given
  Panther Racing an edge on the competition by
  reducing the weight of the car while keeping the
  driver safe.
• Even though it is a very small amount of weight
  that is being lost, anything that can be lost
  from the car in terms of weight can give that
  extra thousandth of a second that is needed in
  order to beat the competition.

17
Conclusions

• Modifications of Original Steel Rocker reduced
  stresses by approx. 30
• 7000 Series Aluminum could successfully be used!
• Maximum Stress 65 ksi
• Increasing Diameters, Radius, and Thickness
  Reduce Stress Around Hole

18
References

• Incropera, Frank, David Dewitt, and Theodore
  Bergman. Fundamentals of Heat and Mass Transfer.
  6th. Hoboken NJ Wilet Sons, 2007.
• Nematollahi, Khosrow. "Oncourse, ME 450."
  Scheduled Reading and Assignments. IUPUI. 23 Nov
  2007 lthttps//oncourse.iu.edu/access/content/user/
  knematol/Filemanager_Public_Files/ME450LectureNote
  sCh13rgt.

19
Questions?
?