Occupant Responses in High-Speed Rear Sled Tests: Focus of Initial Position, Seat Strength and ATD Size

This study evaluates ATD responses in high-speed rear sled tests with various seat designs. Seat designs included modern conventional seats (non-SIR), second row seat integrated restraints (SIR), and rigidized SIRs. Sixteen tests were conducted with the lap-shoulder belted 50th male Hybrid III ATD at 40 km/h, 10 with nominal position and 6 with the ATD leaned forward. The biomechanical responses were below IARV. Lower neck Nij was higher with SIR than non-SIR seats. Head, lower neck and chest responses were higher in the SIR seats when the ATD was leaned forward. Compared to nominal position, the responses were higher with the forward position, increasing the gap between the head/upper torso and seat/head restraint, irrespective of seat type. Six tests were conducted at 56 km/h with the 5th female Hybrid III, 4 in nominal position and 2 leaned outboard. The biomechanical responses were higher in SIR than non-SIR seats in the nominal position. When the ATD was leaned outboard, the head engaged the SIR rigid structures, resulting in high head responses. Two tests were conducted with the 95th male Hybrid III at 56 km/h in two SIR seats. The seatback more than 60 degrees. The ATD kinematics was well controlled when the head, neck and torso were supported early in the 40 and 56 km/h rear sled tests. Overall, seat rotation was higher in non-SIR seats and with heavier ATDs. The responses were similar for the 5th ATD in a conventional seat and for the 95th in a stronger SIR at 56 km/h.