FSAE Suspension
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Transcript FSAE Suspension
ME 191 Final Presentation
Spring 2009
Team Members:
Jarret Vian
Bryan Rowley
John Murray
Introduction
Re-Design
Manufacturing
Testing
Conclusion
Minimum 60” wheel base
Unequal front & rear track widths
Minimum 1” ground clearance
Minimum 2” total suspension travel
Template must pass through frame
Spherical bearings must be in double shear
Design must handle applied loading
Rate of camber angle change with respect to
both body roll and wheel displacement
Original
Final Design
Manufactured at CSUS, by FSAE team
A - Arms
Bearing Holder
Hub & Spindle
Upright
Camber
Caster
Wheelbase
Track Width
Rate of camber angle change per degree
body roll
3.50
3.00
y = 0.7494x - 0.5621
R² = 0.9983
2.50
2.00
1.50
1.00
Camber
0.50
Linear (Camber)
0.00
-0.50
-1.00
0.00
2.00
4.00
6.00
Body Roll (Degrees)
Camber Angle vs. Body Roll
(Experimental)
Camber Angle (Degrees)
Camber Angle (Degrees)
Camber Angle vs. Body Roll
(Theoretical)
1.00
y = 0.7857x - 1.5119
R² = 0.9973
0.50
0.00
-0.50
Camber
-1.00
Linear (Camber)
-1.50
-2.00
0.00
1.00
2.00
3.00
Body Roll (Degrees)
Rate of camber angle change per inch of
wheel displacement
1.00
0.50
y = -0.7564x - 0.5463
R² = 0.9969
0.00
-0.50
Camber
-1.00
Linear (Camber)
-1.50
-2.00
-2.00
-1.00
0.00
1.00
2.00
Wheel Displacement (Inches)
Camber Angle vs. Wheel
Displacement (Experimental)
Camber Angle (Degrees)
Camber Angle (Degrees)
Camber Angle vs. Wheel
Displacement (Theoretical)
0.00
-0.50
-1.00
y = -0.8085x - 1.2266
R² = 0.9633
-1.50
Camber
-2.00
Linear (Camber)
-2.50
-3.00
-1.00
0.00
1.00
2.00
3.00
Wheel Displacement (Inches)
Strain Gages
Degrease
Abrade
Burnish
Condition
Neutralize
M-Bond 200
Solder
Connect to
instrumentation
Apply the load, and maintain a constant force on the tire
139lbs, 300lbs, 400lbs
Read the strain from each channel on the instrumentation
Load
(lbs)
Gage(s)
Rosette 1
139
Rosette 2
Rosette 3
Instrument
Channel
1
2
3
4
5
6
7
8
9
ε
γxy
ε1
ε2
(microstrain) (microstrain) (microstrain) (microstrain)
4
-18
-13
13
12
29
4
-5
-8
σ1
(psi)
σ2
(psi)
Von
Mises
(psi)
-27
11
-20
179
-556
663
-18
33
9
1,156
601
1,001
-6
5
-9
71
-238
280
Rosette 1
Von Mises Stress (psi)
3,000
2,500
y = 5.9793x
R² = 0.9812
2,000
1,500
1,000
500
0
0
50
100
150
200
250
300
350
400
Load (lbs)
Load (lbs)
759
Gage
Rosette 1
Rosette 2
Rosette 3
Von Mises (psi)
4,538
6,415
1,565
Elastic
450
Rosette location
Probe
Theoretical
Stress (psi)
Rosette 1
1,611
Rosette 2
3,358
Rosette 3
565
Gage
Experimental
Percent
Stress (psi) difference
4,538
95%
6,415
63%
1,565
94%
Sy = 50,800psi
Assumption: rigid
Assumption: smooth
Strain
gauge and accelerometer data logged
during driving
Mychron 3 data logger
with internal Accelerometer
Strain gauges
Requirement:
Wheel Base
Unequal track length
Smaller track at least 75% of larger
Minimum 2" total travel
Theoretical
≥ 60"
Experimental (Actual) Pass/Fail or % Diff
61.5"
Front: 48" Rear: 45" Front: 49" Rear: 45"
Pass
Pass
94%
92%
Pass
3"
2.625"
Pass
Template must pass throuh frame
Pass/Fail by design
Pass
Spherical bearings must be in
double shear
Pass/Fail by design
Pass
See test and analysis section
Pass
Material must not fail
Camber vs Displacement goal
-.7654 deg/in
-.8085 deg/in
6.89%
Camber vs Body Roll goal
.7494 deg/deg
.7857 deg/deg
4.84%
PREDICTED COST
ACTUAL COST
MATERIALS
1545
610
BEARINGS
246
130
HARDWARE
232
135
TOTAL
2023
875
Engineering is challenging and rewarding
Never underestimate the scope of a project
Always test to verify assumptions