Experimental Verification of Biomechanical Occupant Response Predictions for Front and Rear Seated Passengers Subjected to Rear Impacts

Airbag induced injuries to front seated infants and children have resulted in US government recommendations that suggest, among other things, the placement of children into the rear seat area of motor vehicles. During a rear impact, however, most conventional automotive front seats occupied by adults will collapse into the rear seat area. This exposes the rear-seated children to other risks of injuries. Rearward load strength tests run on a wide variety of commercially available automotive front seat systems, such as the single or dual sided recliner types and the stronger belt integrated types, demonstrate a wide range of occupant load resistance. Digital human simulation offers a cost effective, efficient, and accurate means for predicting occupant response and interactions influenced by various types of non-linear deforming seat systems, as well as various types of restraints, and vehicle interior structures. In this study, several computer simulations of rear impacts were performed with an available ATB (Articulated Total Body) computer code to demonstrate an efficient and accurate means for assessing the safety performance and hazards associated with occupied front seat collapse into a rear seat area occupied by children. The analysis considered a wide range of different sized front-seated adults (i.e. 50 kg females to 110 kg males), various types of front seats with a range of ultimate non-linear collapse strengths (i.e. 3,220 N up to the 14,500 N level of a Belt-Integrated-Seat), and various impact severities with speed changes between 22 to 45 kph. After performing the analysis several actual sled-buck experimental tests were made, with the same parameter range and a full vehicle interior, to verify and validate the human model predictions for the range of parameters described above.