The most frequently reported injuries resulting from automotive rear impact crashes are neck injuries. More commonly known as whiplash injuries, they are not life threatening though they have been Classified as an AIS 1 injury because of their importance with respect to long term consequences and quantity. There are a multitude of studies carried out to date on human volunteers, cadavers, and animals and still there is no consensus with respect to the injury mechanism. The three mechanisms that have been identified to date are rearward hyperextension, rearward shear or retraction and forward flexion. However, statistical studies have revealed some trends with respect to risk of neck injuries. In particular those that have a higher risk of injury are front seat occupants more so than rear seat occupants, drivers more so than passengers, taller people more so than shorter people and women more so than men. Research evolving from Sweden is proposing that the magnitude of an occupant's rebound velocity may be the major contributing factor when one considers the higher risk situations. Assuming this to be the case, this paper presents an investigation of the physical parameters that influence rebound velocity of a simple torso mass/spring system. Results from a simple MADYMO model indicate that stand off distance, the shape of the crash pulse, occupant weight, and seat stiffness influence the rebound velocity. These results are rationalised against the known higher risk scenarios. The trends that are evident are encouraging and demand further investigation. (a) For the covering entry of this conference, please see ITRD abstract no. E202275.
Abstract