MIE.22 – Design and Validation of Sway Bars for an FSAE Race Vehicle

• Gerardo Almazan
• Jose Erazo
• Jason Garcia
• Lauren Keiser
• Michael Tith

The UIC Formula Society of Automotive Engineers is experiencing an imbalance in their Formula race car’s suspension dynamics during cornering on a track. As the vehicle races around the track, the rear suspension produces oversteer. Oversteer is caused when the rear tires lose traction and spin out the rear end of the car. When this happens, the race car takes a much sharper turn than necessary and can cause the vehicle to experience body roll. Body roll is when the force of the cornering vehicle is pushed towards the outside tires, potentially causing the vehicle to flip outward about its central axis. Oversteer and body roll affect lap times and could lead to more severe problems like crashing. The purpose of this project is to design a component that will rebalance the dynamics of the vehicle’s suspension, specifically by preventing oversteer and decreasing body roll. The components that were chosen to solve this problem were front and rear sway bars. Sway bars are also known as anti-roll or torsion bars. These two different components are customized to fit within the small yet intricate frame of the Formula race vehicle. The sway bar creates a connection between the left and right sides of the vehicle’s suspension, absorbing a vertical force that can be caused by body roll in cornering or bumps as the car moves at high speeds. The vertical force is transferred through torsion applied on the connecting bar that transfers a proportionally inverse vertical force to the opposite side of the suspension. For example, if one tire loses traction and comes off the track, the sway bar will transfer a force to keep the opposite tire down. The sway bars created required two different designs according to available space and connecting components in both the front and rear suspensions. These designs provide stability and control with adjustable stiffness that allow the FSAE vehicle to reach desired lap times but more importantly, support efficiency and safety.