Abstract
The human body dynamics of a belted vehicle occupant in a frontal collision is related to the initial body position and the structural stiffness of the vehicle. Human body dynamics analysis was performed for a 50 percentile male driver restrained by a 3-point seatbelt system under several different conditions. These conditions include five different body positions of the torso, neck and head and two vehicle structural stiffness levels. The human body dynamics analysis involved performing three-dimensional simulations using the Articulated Total Body (A TB) computer program. For the 50 percentile male, the body data set was obtained using the Generator of Body Data (GEBOD) computer program. The acceleration time histories employed in the A TB simulations were based on the results from three-dimensional finite element crash simulations using LS-DYNA3D. The results of the human body dynamics analysis are quantified in terms of linear head acceleration, angular head acceleration, and torque at the occipital condyle. The results of this study indication that: 1) the initial body position is an important factor in the dynamic response of a belted vehicle occupant, 2) due to the asymmetric characteristics of a 3-point seatbelt system, the effect of the initial body position varies with the direction of the initial body rotation, 3) for the initial body rotations as selected for this research, the twisting of the neck and the angular acceleration of the head appear to be the dominant effects in the response and should be considered in the overall injury assessment. Current airbag modifications, such as contour shape and earlier deployment, could minimize the angular motion of the head and neck, therefore reducing the injury potential.