Knee bolsters on the lower instrument panel have been designed to control occupant kinematics during sudden deceleration. However, a wide variability in car occupant anthropometry and choice of seating posture indicates that lower-extremity contacts with the impingement bolster could predominantly load the flexed leg through the knee (acting through the femur) or through the tibia (acting through the knee joint). Potential injuries associated with these types of primary loading may vary significantly and an understanding of potential trauma mechanisms is important for proper occupant restraint. Impacts of the bolster panel against the knee or lower leg were simulated in 10 human cadaver and anthropomorphic dummy tests and anthropomorphic dummy tests and the following aspects were assessed: (1) biomechanical response for lower-extremity impacts, (2) potential mechanisms of skeletal and ligamentous trauma, (3) differences between human cadavers and an anthropomorphic test dummy response, and (4) knee-joint ligament failure characteristics in isolated knee-joint tests.
Abstract