| As an important part of direct contact between automobile body and passengers,automobile seat plays a vital role in the field of passive safety.When an automobile has a frontal collision accident,the seat will be tied with the seat belt to restrain the occupant's sitting posture and prevent the occupant from being injured due to severe deformation in the sitting position.In automobile frontal crash accident,the seat can absorb part of the load generated by the crash through its deformability to reduce the injury to the passengers.Therefore,it is of great significance to study the strength of automobile seat under frontal impact for improving the passive safety performance of automobile.In this paper,the front seat of a certain type of automobile is developed as a mathematical model.The finite element simulation model of the front seat is established by using HyperMesh pre-processing software,and the seat finite element is based on the regulations of GB11550-2009 and GB 14167-2013.The model is carried out with static test of headrest static strength and simulation test of seat belt fixed point strength.The simulation results show that in the static test of the headrest static strength,the maximum back shift of the head module meets the regulatory requirements,and no damage to the seat parts is found in the test.However in the strength test of seat belt fixed point,the displacement of seat belt buckle is large,so it is necessary to optimize the seat belt buckle position.Through the analysis of the stress and strain of the seat belt buckle,the design scheme of increasing the thickness and reinforcing ribs for the parts of the seat belt buckle is put forward.The results show that the displacement of the optimized seat belt buckle is reduced,the passive safety performance of the seat is improved and the strength of the seat skeleton meets the requirements of regulations,which lays the foundation for the subsequent test.Based on the established finite element model of the front seat,LS-DYNA is used to follow by the simulation test of frontal collision which is performed on the Hybrid ? 50%dummy,whose results has validated the effectiveness of the model by comparing with that of the sled test.Meanwhile by combining the injury condition of the dummy chest and the experimental results,it is found that the chest compression and stickiness damage index of the dummy model are all higher than the C-NCAP evaluation criterion of 2018 edition,so the seat frame needs to be optimized.Through analyzing the stress and strain of the seat parts,it is found that the side plate and submergence tube of the original seat frame has undergone so much force and deformation,and an optimization method is proposed to increase the flange and thickness of the side plates,and changing the structure of the submergence tube from straight tube to curved tube,and the material of the submergence tube from Q195 to Q345.The results indicated that,compared with the original seat,the optimized one has decreased the chest compression of the dummy model by 10.19%,and the stickiness damage index of the chest is reduced to 16.52%,meeting the standard requirements.At the same time,the optimized simulation results are compared with the experimental results,to verify the accuracy and reliability of the simulation test,and the results play the role of guiding the design. |
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