SAE Baja Senior Design Project

1. 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

2. Introduction Objective: To design a vehicle for the SAE Baja Competition Competition Events Acceleration Hill Climb Mud Bog Endurance Maneuverability

3. Drivetrain Engine 14.50 ft lbs of Torque ~10 horsepower CVT • 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

4. 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= 7.7551 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-ftavg) = 1.0714 Total FS = (1.0326)(1.0833)(1.0667)(1.0714) ----->Total Safety Factor = 1.2772 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

5. Gear Design- Results Two Stage Reduction Gearbox (8.0:1) Stage 2 - 4.0:1 Size: 20/80 teeth Pitch: 12 Face Width: 1.0 in Stage 1 - 2.0:1 Size: 20/40 teeth Pitch: 12 Face Width: 1.0 in Gear Ratio: A minimum ratio of 7.7551 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.

6. 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

7. 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

8. 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

9. Optimum K • Front suspension modeled in Solid Works • Front suspension modeled in Optimum K • Front suspension has begun testing in Optimum K

10. Frame- Methods • SAE standards • Firewall • Front end • Roll cage • Rear end

11. 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

12. Frame-Results Material-4130 steel tubing Shorter overall length Lighter than previous ODU cars Future: FEA using PATRAN Rollover Test front/rear/ side impact

13. Gantt Chart

14. Questions?