Transcript Slide 1

Suspension
•Peter Morabito
•Michael Paliga
•Brian Ross
Drivetrain
•Kenny Elliot
•Patrick Mooney
•Dylan Quinn
Frame
•Dan D’Amico
•Curtis May
•Greg Schafran
To design a vehicle for the SAE Baja Competition
14.50 ft lbs of Torque
~10 horsepower
•Gaged GX-9 CVT specifically
designed for SAE Baja
•3.85:1 initial ratio
•0.9:1 final ratio
•Double Reduction Gearbox
•8:1 Ratio
Gear Ratio Calculations
Safety Factor Calculations
[Veh. wt]*[Sin(incline angle)] = Repelling Weight
[650 lbs]*[Sin(40 degrees)] = 418 lbs
Rep wt = (tire rad)*(CVT ratio)*(engine tq)*(X min)
418 lbs = (1.0 ft)*(3.85)*(14 lb-ft)*(X min)
----->Xmin= 7.7551
Stage Pitch Teeth
Pitch
Angle
Dp
Face Tangential Load Lewis Form
Width
(lbf)
Factor
Gear Ratio: (8.0/7.7551) = 1.0326
Vehicle Weight: (650 lbs / 600 lbs) = 1.0833
Incline Angle: (40 deg / 37.5 deg) = 1.0667
Torque: (15 lb-ft max / 14 lb-ft avg) = 1.0714
Total FS = (1.0326)(1.0833)(1.0667)(1.0714)
----->Total Safety Factor = 1.2772
Lewis Bending
Stress
Barth Velocity
Factor
Lewis Factor of Barth Velocity Factor
Safety
of Safety
Stress (psi)
stress (psi)
AISI 1020 Steel AISI 1020 Steel Safety
Safety
factor
1
12
20
20
1.6666
1
803.88
0.322
4160.869
10212.609
16.342
6.658
1
12
40
20
3.3333
1
803.88
0.389
6888.431
16907.249
9.871
4.021
2
12
20
20
1.6666
1
1688.148
0.322
8737.826
15092.152
7.782
4.505
2
12
80
20
6.6666
1
1688.148
0.436
25812.660
44584.157
2.634
1.525
Stage 1 - 2.0:1
Size: 20/40 teeth
Pitch: 12
Face Width: 1.0 in
Stage 2 - 4.0:1
Size: 20/80 teeth
Pitch: 12
Face Width: 1.0 in
6.5 inch diameter output gear
allows room for differential
mounting and selection.
Differential
•This year’s more advanced design will incorporate a differential
•Added to increase the vehicles maneuverability
•Wheels will be able to rotate at different speeds
•Better in technical events and in and out of tight turns
•Will be a great help since the vehicle lacks reverse
•Need to determine shaft size to fit differential
What Comes Next?
•Gearbox housing and bearings
•FEA analysis
•Subframe/Mounting
Suspension
Front Suspension
•Basic Double A-arm setup
•Same overall design as previous
years car
•No significant changes, just
modifying to fit newly designed
frame
Rear Suspension
•Using a rear trailing arm set up
similar to the 2012 car
•Eliminating the dynamic toe aspect,
but maintaining the dynamic camber
•Improving wheel travel and reliability
Shock Selection
Fox Float Racing Shocks:
 Adjustable air spring, velocity damping control, and light weight.
 Reduced Cost - $521.25 per pair versus $859 per pair for Custom Works
Shocks.
 Comparable performance
Optimum K
• Front suspension
modeled in Solid
Works
• Front suspension
modeled in
Optimum K
• Front suspension has
begun testing in
Optimum K
Frame- Methods
•SAE standards
•Firewall
•Front end
•Roll cage
•Rear end
Frame- Analysis
• The 2012 ODU Mini Baja (55th place) weighed 479
pounds
• Cornell’s car (3rd place) weighed only 306 pounds
• Reduce frame size and weight
• Eliminate redundant members
Frame- Results
Material-4130 steel tubing
Shorter overall length
Lighter than previous ODU
cars
Future: FEA using PATRAN
Rollover
Test front/rear/
side impact