Optimized Restraint Systems for Various-Sized Rear Seat Occupants in Frontal Crash

Of the injuries sustained by belted rear occupants in a frontal collision event in Japan, the neck and the head are the regions of the body most likely to be injured, while children and female occupants are accounting for the highest rate of injuries. For the purpose of reducing rear seat occupant injuries, the occurrence mechanism of neck and head injuries is clarified by sled tests with the current rear seat belt system. When a high load is applied to the occupant via the seat belt, the occupant experiences sudden deceleration of the chest, resulting in a great relative velocity difference between the head and the chest. This causes injury to the occupant's neck and head. To reduce occupant injuries, therefore, it is important to minimize the relative velocity difference by control of belt load. This paper proposes the concept of optimal belt load control and summarizes parameter study results that have been conducted to verify the validity of the concept using occupant simulation, MADYMO, ranging from 6-year-old dummy (hereinafter “6Yo”), AF05, and AM50 to AM95. Also, in this paper is mentioned the optimal belt control characteristics found through the study.