Seat back and head restraint response during low-speed rear-end automobilecollisions

Automobile seat backs and head restraints play a key safety role during low -speed rear-end collisions, yet few studies have explored the effect of col lision variables on seat response. In this study, the effects of vehicle sp eed change and seat belt use on dynamic seat back and head restraint respon se during low-speed rear-end automobile collisions were examined. Four huma n subjects were repeatedly exposed to vehicle-to-vehicle rear-end collision s with speed changes of 2, 4, 6 and 8 km/h. Seat back force and deflection, and head restraint force were measured. The point of application of the re sultant force applied to the seat back and head restraint were determined. The magnitude and time of peak kinematic and kinetic response parameters we re used in a two-way repeated-measures analysis of variance (ANOVA) for spe ed change and seat belt use. The results showed that 20 of the 24 seat back and head restraint response parameters varied with speed change and none o f the parameters varied with seat belt use. Head restraint forces, seat bac k forces and seat back deflections increased approximately linearly with sp eed change, whereas time to peak response, direction and moment arm of the forces remained either constant or varied only slightly over the range of s peed changes tested. (C) 2000 Elsevier Science Ltd. All rights reserved.