The Influence Of Seat Design Parameters On Neck Injury Risk During Low-speed Rear-end Impact

Over 90% of injuries in rear end impacts are neck injuries. According to traffic accident analysis in Germany, neck injuries often occurred in rear-impacts at low impact velocities, typically less than 25 km/h. So how to prevent neck injuries from low speed rear impacts becomes an increasing problem in the filed of vehicle safety. The aim of present paper was to investigate the relationships between design parameters of seat and neck injuries and reduce the risk of neck injuries in low-speed rear-end impacts by optimizing the seat design parameters. In this paper, finite element method and multi-body method were used.A finite element model of rear-end impact dummy and a laboratory seat denoted V were validated. The validation showed that simulation results agreed well with the volunteer test results. Based on the validation, the rigidity of head restraint and seat back were varied and their influence on neck injury during low-speed rear-end impact were researched by means of Orthogonal Experimental Design (OED) method. In the OED method, Neck Injury Criterion was considered as the main criterion and T1 relative head angle along the Y axis was considered as the secondary criterion. Two kinds of crash pulse were used in the paper. One of average acceleration is 3.1g and delta velocity is 7km/h, the other is 6g and delta velocity is 15km/h.Besides, a multi-body model of rear-end impact were developed and validated.Based on the validation, the influence of distance between head and head-restrain, obliquity of seat back and seat cushion on neck injury were researched.According to simulation results, the following conclusions were made.The simulation results showed that NICmax was reduced by 31.7% andθmax was reduced by 46.3%. Besides, within proper stiffness of springs, the lower stiffness of springs of seat back, especially the stiffness of springs of the upper seat back, the lower NICmax and the better protection from neck injuries.Simulation results of multi-body model showed neck injuries benefit from reducing distance between head to headrestrain and more large or small obliquity of seat back and cushion increase the risk of neck injuries.