1. WyoBaja 2011 SAE Mini Baja Competition Team Leader Suspension Frame
Ken Miech
Suspension
Jason Warner
Kyle Huseth
Jake Thatcher
Frame
Jennifer Daniel
Amy DiRienzo
Drive Train
Dustin Kanada
Kori Cruz
Josh Parker
Bryan Bortner

2. Competition
2011 SAE (Society of Automotive Engineers) Mini Baja Car Competition will be held in Pittsburg, Kansas on May 26th-29th
Single Passenger
-Powered by 10 hp engine
-Must meet SAE design and safety
specifications
5 Event Competition
Acceleration
Sled Pull
Maneuverability
Suspension
Endurance Race

3. Design Goals
Our goal is to design, manufacture, and test a safe, light weight, and competitive off road Baja car. All of the components in the drive train, suspension, and frame were designed to be rigid and lightweight in order to be competitive in the 2011 SAE Baja race in Pittsburg, Kansas.

4. Engineering Specifications
Overall Vehicle Specifications:
Overall vehicle weight under 475 pounds
Comply with 2011 SAE Baja rules and regulations

5. Suspension Specifications
SAE Suspension Requirements:
The vehicle must have four or more wheels not in a straight line.
The maximum vehicle width at the widest point with the wheels pointing forward at static ride height is 64 inches.
The vehicle must have adequate ground clearance and traction.
The vehicle must be capable of safe operation over rough land terrain.

6. Suspension Specifications
WyoBaja Suspension Specifications:
Minimum of 8 inch static ride height
Minimum of 10 inches of suspension travel
Maximum turning radius of 13 feet
Camber angle of -2° at static ride height, up to a maximum of -7° at full compression
Castor angle of 5° for steering return-to-center
Rear wheel frequency 15% higher than the front

7. Suspension Specifications
Suspension Morphology
Solid with Leaf Springs
Solid with Coil Springs
Swing Axle with Coil Spring
Trailing Arm with Coil Spring
Single A-arm with Coil Spring
Dual A-arms with Coil Spring

8. Suspension Detailed Design
Coil-Over Shocks:
Remote reservoir
Dual coil-over springs
Springs are replaceable
Preload adjustment
Adjustable damping coefficient

9. Suspension Mathematical Modeling
Dynamic Modeling of Baja Suspension M Mt k kt b bt Y X U
𝑌(𝑠) 𝑈(𝑠) = 𝑏 𝑡 𝑏 𝑠 2 + 𝑏 𝑘 𝑡 − 𝑏 𝑡 𝑘 𝑠+ 𝑘 𝑡 𝑘 𝑚 𝑡 𝑚 𝑠 4 + 𝑚 𝑏+ 𝑏 𝑡 +𝑏 𝑚 𝑡 +𝑚 𝑠 3 + 𝑚 𝑘 𝑡 +𝑘 + 𝑏 𝑡 𝑏+𝑘 𝑚 𝑡 𝑠 2 + 𝑏 𝑘 𝑡 + 𝑏 𝑡 𝑘 𝑠+ 𝑘 𝑡 𝑘

10. Suspension Mathematical Modeling
Suspension Behavior for a 10 inch bump

11. Suspension Detailed Design
Rear Suspension Specifications
Wheel Travel (inches)
8.8 in
Maximum Vehicle Width (inches)
54.9
Ground Clearance
8.9

12. Suspension Detailed Design
Rear at Full Compression and Full Droop

13. Suspension Detailed Design
Rear Suspension at Ride Height

14. Suspension Detailed Design
Front Suspension Specifications
Wheel Travel (inches)
10.8 in
Max Vehicle Width (inches)
58.1
Ground Clearance
8.9

15. Suspension Detailed Design
Front at Full Compression and Full Droop

16. Suspension Detailed Design
Front Suspension at Ride Height

17. Suspension Specifications
Compliance Testing
Suspension geometry closely matches design specifications
Suspension model testing will be completed once the vehicle is drivable
Suspension strength testing will be completed once the majority of the vehicle components are installed

18. Drive Train Configuration
Problem: Re-use CVT ? Planetary Gear Box ? Differential ?

19. Drive Train Configuration
CVT
Planetary
Gear Box
Rear
Wheel
Engine
Solution:
Differential
Chain & Sprockets

20. Mathematical Modeling
Problem:
Calculate Overall Gear Ratio
-allowed for sizing of new
chain & sprocket set-up →
Need to:
- model speed alteration through drive train
-estimate of drive train efficiency

21. Mathematical Modeling
Solution:
Top Speed & Rolling Resistance Tests
→Average: 19 mph (± 1.5) and 110 lbf (± 5)
Target Speed: 27 mph
Required Chain & Sprocket Gear Ratio: 2:1

22. Additional Testing
Top Speed repeated Braking for compliance testing Towing & Acceleration performance testing

23. Frame Specifications Meet all SAE specifications
Accommodate suspension and drive train components
Protect the driver

24. Recommendations
Tighten the envelope of the roll cage to meet the minimum SAE regulations
Widen the feet/pedal area for a more comfortable position
Determine the best welder to weld the frame
Use different sizes of tubing for primary and secondary members

25. Frame Design All members Minimum 1” diameter 0.18% carbon content
Red members
Minimum 0.12”
wall thickness
Blue members
Minimum 0.035” wall thickness
Driver Clearance
6” above helmet
3” from appendages

26. Component Accommodation
Areas of High Stress
FS=5.80

27. Driver Safety: Front Impact
Areas of
High Stress
FS=4.26

28. Driver Safety: Rollover
Area of
High Stress
Areas of High Stress
FS=6.29

29. Driver Safety: Side Impact
Areas of High Stress
FS=3.00

30. Manufacturing: Welding
90° Weld Sample
30° Weld Sample
Penetration Sample

31. Compliance Results

32. Frame Conclusions Designed rigid, safe, and lightweight frame
Meets design goal of FS≥3
Dropped 25 lb. from last year’s design
Meets all SAE Specifications
Incorporates other subsystems
Protects the driver
Follows all recommendations made by previous team

33. Costs Design labor cost – $54,490.38 New part cost – $4,112.71
Reused part cost – $4,446.62
Prototype cost – $63,049.71
Construction cost – $16,490.00
Production cost - $25,049.33

34. Questions ???