Experimental analysis of a new flexible neck model for low-speed rear-end collisions.

Whiplash injuries occur frequently in rear-end automobile accidents even at low-speed. The hybrid III dummy has been used for various tests in order to investigate the mechanism of whiplash injuries. However, since this dummy neck is too rigid for low-speed collisions, we developed a new flexible neck model for low-speed rear-end collisions. Each component of this new flexible neck model is made of polymers with material properties close to those of the human body. Sled tests were conducted to measure the displacements of cervical vertebrae of the new flexible neck model at 11 km/h. The figures of s-shape and shear displacement in the plane of the intervertebral disks were observed, and it was recognized that shear displacement resulted from the inconsistency of motion between the head and neck. The regions of shear displacement agreed well with the statistics of the critical regions where whiplash injuries have frequently occurred. It is assumed that shear displacement is one of the causes of the mechanism of whiplash injuries.