Design Targets of Seat Integrated Restraint System for Optimal Occupant Protection

Unlike the conventional seat belt system wherein the shoulder belt upper anchor is mounted on the vehicle body, Seat Integrated Restraint (SIR) system has the shoulder belt upper anchor mounted on the top of seat back frame. During a vehicle frontal impact, the stiffness of seat and that of the floor underneath the seat play a significant role in the performance of the restraint system in providing protection to the occupants. In this study the effect of the stiffness of seat and floor on the restraint system is investigated with other restraint parameters such as retractor load limit, fire time lag of dual stage inflator and air bag vent size. The stiffness of seat and floor is varied to determine the range of best occupant protection. This study attempts to establish feasible design targets of seat and floor stiffness for optimal restraint performance.