In this poster presentation, it is stated that cervical spine distortion (CSD) injuries in passenger car rear-impact accidents, in particular at low speeds with a delta V (velocity change) of 15 km/h or less, are becoming increasingly problematic. Basically, there are by now two different systems for CSD injury reduction on the market: active headrest and yielding backrest. Both systems reduce the relative movement between the head and thorax in rear impact; the latter one by reducing thorax acceleration. The yielding backrest has the advantage of reducing head rebound speed and offering protection with wrongly adjusted headrest, as well. Based on the yielding backrest working principle, the authors developed a neck protection system called "Anti Whiplash System" (AWS; will be available for a first car model from Fall 2001). Because aftermarket installation of an energy-absorbing recliner in an existing seat design appeared unsuitable, the authors decided to integrate the deformation element in the seat rail. In this solution, the entire seat moves backwards with the desired motion. The AWS installation also means optimum protection for both small, lightweight and large, heavy persons. The benefit of this aftermarket CSD system was assessed by sled tests using a BioRID II as dummy and by MADYMO simulation using HIII 5th percentile female and 95th male.
Abstract