A Study On Occupant's Brain And Cervical Spinal Cord Injury In Rear-end Vehicle Collision

Thanks to the rapid development of the economics,people's living standard has been improved and the number of people who own cars has gone through a great increase,the traffic situation in our country is extremely complex as well,which have led to the high frequency of traffic accidents.Up to now,related researches about passenger's injury have been performed,while the injury mechanisms still remain controversial,especially the head-neck injury tolerance of soft tissues under various impact intensities and effects from the constraints system.Hence carrying the related researches is of great meaning of theory and reality.The research was aimed at developing a mixed dummy finite element model with high bio-fidelity and utilizing the model in studying injuries of head and neck under various rear-end impact intensities.In addition,the research also studied the influence of the seat on passenger's head-neck injuries.Firstly,a cervical spinal cord FE model was developed based on the MRI images of a volunteer' neck and the model was validated under axial tensile,radial compression and radial impact according to previous researches.The validated spinal cord model was integrated into the basic head-neck model developed by Hunan University and the head model with detailed brain structures developed by Yan JK was utilized in replacing the rigid head of the basic head-neck model.The improved head-neck model was validated by the volunteer test performed by Davidsson et al.In order to improve the compute efficiency and the bio-fidelity,the improved head-neck model was used to replace the head-neck part of BioRID?dummy to develop a mixed dummy FE model.The mixed dummy FE model coupled with the seat and seatbelt,were validated according to Davidsson's research.Then the mixed model was utilized in studying the kinematic and biomechanical responses of head neck under various rear-end impact intensities.Finally,the model was impacted by the pulse from FMVSS202 regulation and the effects of the seat on head neck injuries of passenger were studied,which may help in improving the safety of seat.The results showed that the spinal cord model had high bio-fidelity under axial tensile and radial compression as well as radial impact condition.The dynamic responses of the improved head-neck model and the mixed dummy model were in well agreement with the experimental corridors and the models had good bio-fidelity in passenger's injury researches.The skull mainly suffered the shear stress and contained high injury risks in medium rear-end impact intensity.The soft tissues of head and neck mainly suffered pressure stress under various rear-end impact intensities.The pressures of both cerebrum and cerebellum increased as the impact intensity improved and they suffered the highest shear stress in medium rear-end impact intensity.Both of white and gray matters were easy to suffer high injury risks in medium impact intensity,while the risk of gray matter was higher than that of white matter.To protect the safety of passenger,appropriately minimizing the horizontal distance and increasing the vertical distance between head and headrest as well as weakening the stiffness of headrest would be necessary.