Lightweight Knee Bolster Assembly for Belted and Unbelted Occupant Restraint in a Frontal Crash

Automotive knee bolster requirements have changed substantially in recent years due to expanded safety requirements. A three-piece cellular structural knee bolster assembly has been evolved to meet this matrix of requirements while being extremely lightweight (as low as 0.7 Kg), low in cost and easily tunable to work in various car/truck programs. The energy absorber is the primary component of this assembly and allows for a range of occupant sizes and weights to be restrained (from 50 Kg/152 cm 5^th percentile female to 100 Kg/188cm 95^th percentile male occupants). The evolution of this knee bolster assembly design is described using crush analysis, component testing to validate the crush analysis, instrument panel assembly level analysis with occupant models and sled tests. Steel and aluminum versions of this knee bolster are compared - in terms of weight, cost, design tunability for various crash conditions, structural stiffness etc. It is shown that this lightweight cellular structural knee bolster can help the OEMs meet various safety requirements and achieve 4 or 5 star frontal crash rating.