Analysis of Driver Kinematics and Lower Thoracic Spine Injury in World Endurance Championship Race Cars during Frontal Impacts

This study used finite element (FE) simulations to analyze the injury mechanisms of driver spine fracture during frontal crashes in the World Endurance Championship (WEC) series and possible countermeasures are suggested to help reduce spine fracture risk. This FE model incorporated the Total Human Model for Safety (THUMS) scaled to a driver, a model of the detailed racecar cockpit and a model of the seat/restraint systems. A frontal impact deceleration pulse was applied to the cockpit model. In the simulation, the driver chest moved forward under the shoulder belt and the pelvis was restrained by the crotch belt and the leg hump. The simulation predicted spine fracture at T11 and T12. It was found that a combination of axial compression force and bending moment at the spine caused the fractures. The axial compression force and bending moment were generated by the shoulder belt down force as the driver’s chest moved forward. The axial compression force at the spine was also induced by the forces from the crotch belt and the leg hump. Based on these mechanisms, the modifications were made to help reduce the spine fracture risk. The seat back angle was raised, the shoulder belt anchor was lifted, the crotch belt anchor was moved forward, the seat pad thickness was increased and the seat pad stiffness was reduced. These modifications allowed more forward motion of the pelvis and reduced the shoulder belt down force, and generated no spine fracture.