Experimental Analysis and Validation of Torsional Stiffness of Tubular Space Frame Chassis.

Abstract Chassis is the pat that integrates all components of the vehicle and withstands the load. This load includes the weight of each component and the force that occurs when the vehicle is moving (acceleration, deceleration, and cornering). Chassis should also absorb energy when a collision occurs. The chassis provides a path for the forces that act on it. The suspension pickup points on the chassis are an important parameter in determining the suspension geometry of the vehicle. Torsional Stiffness is determined by the amount of Torque required to deflect the chassis by unit degree. The differences in forces from the suspension linkages that leads to a Twisting Moment. The moment will deflect the chassis about its Roll Axis. Predictable handling of a race car may be achieved by tailoring sis stiffness so that roll stiffness between sprung and un-sprung masses is due almost entirely to the suspension. In this work, the effects of overall chassis flexibility on roll stiffness will be determined using a finite element model (FEM) of a Formula Student Chassis and suspension. The Validation of the model is done by designing and fabricating a test rig to experimentally determine the Torsional Stiffness. The Suspension linkages are replaced with equivalent length solid tubes to eliminate the suspension compression. The test rig will be capable of applying force through one of the front wheel hubs, the other end of the front axle is kept at zero load. The deflection in chassis can be calibrated using a dial gauge. The objective of this project is to Design and optimize the design of the chassis for meeting the Chassis Stiffness target value to obtain the best Lateral Dynamics. Increasing the Torsional Rigidity will reduce the twist in the Chassis, improving vehicle handling by allowing the suspension components to control a larger percentage of a vehicle's kinematics.