Energy absorbing car seat designs for reducing whiplash

Objective. This study presents an investigation of anti-whiplash features that can be implemented in a car seat to reduce whiplash injuries in the case of a rear impact. The main emphasis is on achieving a seat design with good energy absorption properties. Methods. A biofidelic 50th percentile male multi-body human model for rear impact is developed to evaluate the performance of car seat design concepts. The model is validated using the responses of 7 volunteers from the Japanese Automobile Research Institute (JARI) sled tests, which were performed at an impact speed of 8 kph with a rigid seat and without head restraint and seat-belt. A generic multi-body car seat model is also developed to implement various seatback and recliner properties, anti-whiplash devices and head restraints. Using the same driving posture and the rigid seat in the JARI sled tests as the basic configuration, several anti-whiplash seats are designed to allow different types of motion for the seatback and seat-pan. Results. The anti-whiplash car seat design concepts limit neck internal motion successfully until the head to head restraint contact occurs and they exhibit low NICmax values (7 m2/s2 on average). They are also effective in reducing neck compression forces and T1 forward accelerations. In principle, these car seat design concepts employ controlled recliner rotation and seat-pan displacement to limit the formation of S-shape. This is accomplished by using anti-whiplash devices which absorb the crash energy in such a way that an optimum protection is provided at different severities. Conclusions. The results indicate that the energy absorbing car seat design concepts all demonstrate good whiplash reducing performances at the IIWPG standard pulse. Especially in higher severity rear impacts, two of the car seat design concepts reduce the ramping of the occupant considerably.