Energy-Absorbing Wheel Tethers for Racecars

Wheel tethers are frequently used on racecars to prevent detached wheels from flying freely away from the car and injuring spectators. Extremely stiff tethers may cause the wheel assembly to be either yanked back toward the car, putting the driver in danger or to be snapped free at an uncontrolled trajectory, exposing spectators, other drivers, and workers to danger. Conceptual design of energy absorbing wheel tether systems was performed using the finite element program LS- DYNA. Two major approaches to energy absorption were explored, both of which involved metal bending. For absorbing energy through sheet metal bending, parametric studies showed that a minimum of 4 through-the- thickness integration points were required to capture good elasto-plastic behavior of shell elements. Additionally, for absorbing energy through solid tube bending, it was found that a circular cross-section in elasto-plastic bending must be modeled with a minimum of 12 solid elements in the cross-section. The developed tether design was able to absorb a total of 10 kJ of kinetic energy from the wheel assembly. This amount of energy is equivalent to reducing the trajectory height and distance of a 68-kg w