Analysis of Intervertebral Strain Response during Rear Impact Using Head-Neck Finite Element Model

Minor neck injuries in rear collision accidents have become a huge problem in many countries. Therefore, it is urgent to develop a suitable criterion for assessing neck injury risk. In this study, a detailed head-neck finite element (FE) model was developed. Skull and vertebrae models were created based on CT images of a typical Japanese male. Models of intervertebral discs, ligaments and muscles were also created according to literatures. Furthermore, material properties were taken from the published data. In order to evaluate intervertebral soft tissue strain due to translational rotational coupled motion of vertebrae, a 2D strain analysis method was also proposed. The method was applied to cervical vertebral motion data obtained from previous rear impact tests using human volunteers and from test reconstruction using the head-neck model. A potential correlation between intervertebral strain and neck injury was clarified from the comparison between the intervertebral strain level and existence of neck discomforts. The model’s response is also in good agreement with the volunteers’ response, indicating that the head-neck model is suitable for minor neck injury analysis and that it is possible to analyze the intervertebral strain with a head-neck model.