SAE Baja Senior Design Project

SAE Baja Senior Design Project Final Presentation • Suspension • Peter Morabito • Michael Paliga • Brian Ross • Drivetrain • Kenny Elliot • Patrick Mooney • Dylan Quinn • Frame • Dan D’Amico • Curtis May • Greg Schafran

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

Drivetrain Goals: • Accomplish 8:1 Gear Ratio through the gearbox • Create the smallest and lightest gearbox possible • Extra design considerations includes machinability • cost, ease of maintenance

Drivetrain: Calculations Hand Calculations were completed for the Lewis Bending stresses, Barth Velocity Stress, and AGMA gear stresses Solidworks FEA was used to model the expected maximum stress and maximum displacement

Gear Design- Methods Our calculations were based on methods found in Shigley’s Design manual. Gear Ratio 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 After determining the specific gear selections we also analyzed each gear for: • Minimum Face Width • Interference • Lewis Bending Stress • AGMA Stress and Strength • Barth Velocity Factor • Basic FEA in Solidworks

Gear Design- Results Two Stage Reduction Gearbox (8.0:1) Stage 2 - 4.0:1 Size: 20/80 teeth Pitch: 12 Face Width: 1.5 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. We chose 8.0:1, a SF or 1.277 Max torque at wheels: 446 lb-ft Top Speed: 35.7 MPH at 3600 RPM. Gear Material: AISI 4130 Minimum Safety Factor of 1.89 6.5 inch diameter output gear allows room for differential mounting to increase vehicle handling.

Drivetrain: Materials, Weight • ANSI 4130 Steel was chosen for the gear material • because of high yield strength and the • and because of surface properties in reducing fatigue • Case material chosen was 6061 Aluminum Alloy for • Ease of machining and its weight properties • Total Conservative weight estimate is 40 lbs

Drivetrain: Mounting and Simulation Hinge style mount Simulation:

Suspension- Overview • 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

Suspension-Optimum K Model REAR FRONT ASSEMBLY

Suspension- Optimum K Output • Steering wheel angle vs. steering angle (front left) • Motion is of a body roll

Suspension- Optimum K Output • Camber angle (rear right) • Motion is of a body roll

Suspension- Optimum K Output • Camber Angle (rear right) • Motion is of a jump

Suspension- Optimum K Output • Camber angle (front right) • Motion is of a jump

Suspension- Geometry FEA - Stress TRAILING ARM FEA - Displacement 1’’ X 0.065’’ 4130 STEEL

Suspension- Geometry FEA - Stress UPPER A-ARM 1’’ X 0.065’’ 4130 STEEL FEA - Displacement

Suspension- Geometry FEA - Stress LOWER A-ARM FEA - Displacement 1’’ X 0.065’’ 4130 STEEL

Suspension- 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

Frame- Methods • SAE standards • Firewall • Front end • Roll cage • Rear end • Finite Element Analysis

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: primary members: 1.25”x.065 secondary members: 1”x.065 Shorter overall length Lighter than previous ODU cars: 63.7 lbs.

Frame-Results

Gantt Chart

SAE Baja Senior Design Project