A Study On Neck Injury Mechanism And Occupant Prevention In Rear-end Impacts Based On Muscle Activation

In vehicle traffic accidents, neck injury is one of the most common types of injury with severe consequences. Their long-term consequences lead to great physical harm and huge economic loss to victims. In recent years, great studies have been carried out by the researchers, but the neck injury mechanism is still controversy because of the complex anatomical structure of human neck. Therefore, to find out the neck muscle influence related to neck injury mechanism would be significant to reduce neck injuries.The aim of this study was to develop a head-neck FE model that could simulate neck muscle activation behavior, and to validated this model via volunteer rear-impact tests. The model was then used to study the effect of neck muscle behavior to the dynamic response of human neck and injury mechanism during rear-impact accidents, in order to provide theoretic basis for occupant injury prevention.Firstly, the three dimensional model of human neck muscles was reconstructed via MRI of a 50% male human. The 3D model was scaled and connected to a well-validated head-neck FE model using Kriging method. The neck muscle FE model was developed based on the 3D model and the material behavior was defined via literature data. The head-neck model with neck muscle activation was validated via volunteer impact test contacted by Davidsson et al. Then a FE model for occupant neck injury biomechanics study(the hybrid FE model) was developed. This model consisted of the head-neck FE model, the Bio RID II dummy FE model(torso parts),occupant seat model and seat belt model. The hybrid FE model was validated via rear-impact volunteer test. Finally, the effect of impact impulse and seat design parameters on neck injury risks was investigated by using the developed FE model for occupant neck injury biomechanics study in rear impact.The result shows that the developed head-neck FE model has a good biofidelity and can be used to study real rear-impact dynamic response of human neck. The active response of neck muscles is of a great influence on the neck dynamics in rear impact, especially in low speed impact, that could reduce the injury risks of head and neck. The hybrid FE model could be used to simulate and analyze ligaments elongation, loads and stresses of disks, as well as stresses of vertebrae with a goodbiofidelity. Increasing impact acceleration results in more serious neck injury risks.By increasing the head rest height, reducing headrest distance and softening seat back cushion could reduce neck injury risks.