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

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

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.

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

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.

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

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

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

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

Suspension Mathematical Modeling Suspension Behavior for a 10 inch bump

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

Suspension Detailed Design Rear at Full Compression and Full Droop

Suspension Detailed Design Rear Suspension at Ride Height

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

Suspension Detailed Design Front at Full Compression and Full Droop

Suspension Detailed Design Front Suspension at Ride Height

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

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

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

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

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

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

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

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

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

Component Accommodation Areas of High Stress FS=5.80

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

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

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

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

Compliance Results

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

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

Questions ???