Effect Of AEB On Head And Neck Injury Of Occupant In Small Offset Collision

In traffic accidents,the number of deaths caused by small offset collision is more than a quarter.With the application of vehicle active safety technology,the phenomenon that the protection effect of restraint system is reduced due to the occupant’s out of position under AEB braking is also concerned,and the lateral acceleration generated by small offset collision will aggravate the out of position and make the occupant suffer greater risk of injury.The head and neck are the most vulnerable part of the occupant,so the effect of AEB on the degree and mechanism of injury needs to be studied.The purpose of this paper is to develop a finite element model of occupant dummy with detailed head and neck structure,and to study the effect of AEB and neck muscle activation on the degree and mechanism of head and neck injury through simulation tests at different speeds.Based on the HBM-Head-Neck FE Model,this paper uses the head model developed by Yang Jikuang with detailed structure to replace the original twodimensional skull,and uses Kriging interpolation method to assemble the neck muscle model with activation developed by volunteers’ neck MRI to the corresponding position,and uses the same method to develop the spinal cord model in the cervical spine,then a hybrid head-neck model with detailed head and neck structure was developed.Using the above head-neck model to replace the head and neck part of the Hybrid III dummy,then the finite element model of the hybrid occupant dummy is developed.Through vehicle model simulation test,the acceleration curve of vehicle in small offset collision at different speeds is obtained as the boundary condition,and the control logic and braking acceleration curve of AEB in relevant literature are used as the input boundary of AEB to study the effect of different working conditions and neck muscle activation on head and neck injury of occupants.The results show that AEB can aggravate occupant’s out of position and lead to higher risk of head injury,which increases with the increase of collision speed.At low speed,the neck muscle activation can stabilize the head and reduce the injury,but at high speed,the effect is not obvious.In the injury mechanism,AEB can change the injury site of the head and neck,and increase the equivalent stress of each structure.The neck muscle activation can increase the stress on the cervical vertebrae and reduce the stress on the head structure,but has no significant effect on the intervertebral disc and spinal cord.The effect degree of AEB and muscle activation on skull,cervical vertebra and intervertebral disc varies with the collision speed,but the effect on soft tissue is not affected by the speed.In the form of stress,the skull and cervical vertebra are mainly compressed and sheared;the intervertebral disc and spinal cord are mainly stretched and sheared;the brain and cerebellum are mainly compressed while the brain stem is stretched.