# SAE Baja Senior Design Project

## Presentation on theme: "SAE Baja Senior Design Project"— Presentation transcript:

SAE Baja Senior Design Project
Midterm Presentation 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
Introduction Objective: To design a vehicle for the SAE Baja Competition Competition Events Acceleration Hill Climb Mud Bog Endurance Maneuverability

Drivetrain Engine CVT Gearbox 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 Gearbox Double Reduction Gearbox 8:1 Ratio

Barth Velocity Factor of Safety AISI 1020 Steel Safety factor
Gear Design- Methods Our calculations were based on methods found in Shigley’s Design manual. 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= Gear Ratio: (8.0/7.7551) = Vehicle Weight: (650 lbs / 600 lbs) = Incline Angle: (40 deg / 37.5 deg) = Torque: (15 lb-ft max / 14 lb-ft avg) = Total FS = (1.0326)(1.0833)(1.0667)(1.0714) ----->Total Safety Factor = After determining the specific gear selections we also analyzed each gear for: Face Width Interference Lewis Bending Stress AGMA Stress and Strength Barth Velocity Factor Lewis Bending Stress Barth Velocity Factor Lewis Factor of Safety Barth Velocity Factor of Safety Stage Pitch Teeth Pitch Angle Dp Face Width Tangential Load (lbf) Lewis Form Factor Stress (psi) stress (psi) AISI 1020 Steel Safety AISI 1020 Steel Safety factor 1 12 20 1.6666 803.88 0.322 16.342 6.658 40 3.3333 0.389 9.871 4.021 2 7.782 4.505 80 6.6666 0.436 2.634 1.525

Gear Design- Results Two Stage Reduction Gearbox (8.0:1)
Size: 20/40 teeth Pitch: 12 Face Width: 1.0 in Stage :1 Size: 20/80 teeth Pitch: 12 Face Width: 1.0 in Gear Ratio: A minimum ratio of was calculated and 8:1 chosen to provide extra torque Top Speed: 35.7 MPH at 3600 RPM. Face Width Required: 1.0 inches Gear Material: AISI 1020 Total Safety Factor (torque output): 1.277 Lewis Safety Factor (minimum): 2.63 6.5 inch diameter output gear allows room for differential mounting and selection.

Differential What Comes Next?
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 - \$ 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

Gantt Chart

Questions?