Research On Optimum Design Of Automobile Front Structure Based On Multiple Collision Conditions

With the development and progress of society,the per capita ownership of automobiles is increasing day by day.People put forward higher requirements on the safety,energy saving and environmental protection of automobiles,among which ensuring and improving the safety of automobiles is the first consideration.Vehicle frontal collisions is a common form of traffic accidents.Improving the crashworthiness of vehicle frontal crash is an important part of passive safety research.At present,most of the studies are carried out under the same working condition,which has obvious limitations in improving the crashworthiness requirements of frontal collisions from different angles.At the same time,the approximate model technology is the most commonly used method in optimum design,but the traditional method shows obvious inadequate fitting accuracy when dealing with strong non-linear problems.In order to solve the above problems,this paper combines two frontal collision conditions in C-NCAP.And the experimental design method,improved approximate model technology,multi-objective optimization method and reliability optimization theory are applied to the optimization design of automobile front-end structure.Aiming at the optimization problem,the finite element simulation models of 100% overlapping rigid barrier collision and 40% overlapping deformable barrier collision on the front of a car are established and tested.The results show that the simulation results are in good agreement with the actual vehicle test results.In order to improve the prediction accuracy of the approximate model,particle swarm optimization(PSO)is applied to optimize the parameters and kernel function parameters of the support vector regression(SVR)model,thus an approximate model with higher prediction accuracy than the traditional method is constructed.Based on the high precision approximate model,deterministic optimization are carried out for two conditions of frontal collision,and the reliability of deterministic optimization solution is evaluated.In order to solve the problem of insufficient reliability of constrained response due to the change of design variables,the reliability optimization design is carried out on the basis of deterministic optimization design.The optimization results show that the reliability of each response of the reliability optimization design results is improved to more than 99% compared with the deterministic optimization results.Compared with the initial design,the total energy absorption,peak acceleration and maximum firewall intrusion of the vehicle under two crash conditions are improved and the quality is reduced.At the same time,the maximum relative error between the predicted value and the simulated value of the approximate model is only 1.64%,which verifies the accuracy of the approximate model described in this paper.All in all,the crashworthiness and lightweight level of the vehicle have been improved through the optimization design process in this paper.