Kinetic and Kinematic Responses of the RID2a, Hybrid III and Human Volunteers in Low-Speed Rear-End Collisions.

An anthropomorphic test device (ATD) which accurately models the kinematic and kinetic responses of human subjects during head restraint contact in low-speed rear-end collisions is needed to evaluate present and future seat and vehicle designs. The primary goal of this study was to quantify the biofidelity of a new rear-impact ATD, the RID2a, by comparing its dynamic response to those of human subjects under identical test conditions. For this study, a RID2a and a Hybrid III ATD were each exposed to 10 low-speed rear-end collisions: five at a speed change of 4 km/h and five at a speed change of 8 km/h. Sagittal plane kinematics of the head and upper torso, head restraint contact forces, and the reaction loads and moment at the atlanto-occipital joint were determined and compared to the response of eleven male human subjects. Both ATDs produced repeatable response corridors. As observed by others, the Hybrid III did not replicate many features of the human response. Aside from the vertical response of the head and T1 in the global reference frame, the kinematic and kinetic responses of the RID2a reproduced most features of the human response. Head restraint forces observed in both the human subjects and the RID2a contained large vertical components that placed the neck in tension during head restraint contact. The results of this study indicated that the RID2a was able to model the overall kinematic and kinetic responses relevant to some recently-proposed mechanisms of whiplash injury.