抄録
The Active Head Restraint system that was introduced in the market is 'for helpingg to reduce whiplash injury risks by the movable head restraint. This system activate by the inertia force of the occupant when the rear-end collision happened. This effect can be arised by reducing the horizontal and longitudinal gaps between head restraint cushion and back part of thee head. In this research, detailed FEM and multi-body model were constructed for investigating the relation between the gap distance and injury risks. In that modeling, initial load between dummy and cushion when dummy sat on the seat statistically is important. In this paper, the modeling method and the relation between the gap distance and injury risk were introduced.