Optimal Restraint Characteristics for Minimization of Peak Occupant Deceleration in Frontal Impact

In automobile frontal impact, given the vehicle motion and the interior free space for the occupant’s excursion, what are the optimal characteristics of restraint systems for the minimization of the peak occupant deceleration? In this paper, based on a lumped-parameter model of the occupant-vehicle system, the optimal kinematics of the occupant in frontal impact is investigated first. The optimal characteristics of passive restraint systems are then investigated in detail for three types of vehicle crash pulse: optimal pulse, constant deceleration pulse, and half-sine pulse. Optimization of the characteristics of active and pre-acting restraint systems is addressed. It is found that the optimal kinematics of the occupant in frontal impact is such that the occupant moves at a constant deceleration. Passive restraint systems are not able to provide required protection for the occupant to attain optimal kinematics, but active and pre-acting restraint systems can achieve that if optimally designed.