Research On Topology Optimization Of Booster Seat And Safety Of Child Occupants Based On R129

With the increasing number of cars,more and more children travel by car,but the seats and safety devices in the car are not suitable for children's body size.A large number of children in China die in traffic accidents every year,most commonly in frontal impact patterns.This is mainly due to the low utilization rate of child safety seats,misuse,etc.The child safety seat itself is too heavy and the seatbelt path is not clear or inappropriate,resulting in a very low rate of equipment in vehicles and very poor protection effect.In this paper,the structure optimization and seat belt path optimization of the child booster seat are carried out.The purpose of this paper is to decrease the weight of the booster seat,improve ease of use and energy efficiency,and study the optimal design method of seat belt restraint paths to improve the safety of child occupants in collision.In this paper,through the finite element mesh division of the original three-dimensional model of the booster seat,the collision simulation model of the booster seat is constructed in MADYMO.The calculation of the model is based on the multi-rigid body dynamics and finite element analysis method,and the simulation model of the booster seat is verified by experiments.Using the verified booster seat model,on the one hand,the frontal impact simulation model of Q series 6-year-old dummy based on ECE R129 regulation is constructed to ensure its correctness and then be used in the research of seatbelt path optimization,and the full-factor design of experiment method is adopted,combining the three levels of shoulder and lap belt guide,to obtain the optimal seat belt path design scheme.On the other hand,the topology optimization method and size optimization method are used in Optistruct software to study the optimization of the shell topology and the ribs size,to make the booster seat lightweight and determine the optimization scheme of the booster seat structure.In order to ensure the safety of the optimized structure,the statics analysis method is used to carry out the feasibility analysis.Finally,the frontal impact simulation model is constructed by using the structural optimization scheme of the booster seat,and the effects of structural optimization,seatbelt path optimization and the synthesis of these two optimization methods on the safety of the child occupants are studied respectively.The results show that after iterative calculation of the shell topology optimization and ribs size optimization,the weight of the booster seat model can be reduced by 17.4%and 12.1%,respectively.After the optimization results are improved,the weight is reduced by 11.8%.Further frontal impact study shows that the head injury index of Q6 child dummy decreases significantly after structural optimization,by a maximum of 10.3%,and head safety performance indexes improve significantly.The change of chest injury index is small,and it does not affect the safety of child occupant basically.In addition,after 9 groups of simulation,an innovative comprehensive injury evaluation index(C₁₂₉)for children has been put forward to make quantitative evaluation of dynamic impact,and the seat belt fit evaluation method is applied to evaluate statically.According to the analysis above,the optimal seatbelt path is obtained,that is,the original belt guide position is 20 mm downward and the shoulder belt guide position is upward offset 20mm.After comparison,the analysis shows that the head and chest safety performance of the child dummy are greatly improved.The head injury values decrease to a maximum of 16.8%and chest injury values decrease to a maximum of 20.4%.After synthesizing the above two kinds of optimization,the simulation results show that the head injury values decrease to a maximum of 19.5%and chest injury values decrease to a maximum of 18.6%.The comprehensive optimization can maximize the safety of the child occupants and reduce the weight of the booster seat structure by 11.8%.In summary,the above research methods and conclusions are of guiding significance for the optimization design of the booster seats.