The Refined Simulation And Optimization Of Carbon Fiber Body Structure

The lightweight and crashworthiness of the car body is an important index to measure the quality of the automobile.How to take into account the relationship between the two is an important issue in the field of automotive engineering.The performance of composite material is excellent,and its application is more and more widely.It is an effective way to solve the two contradictory propositions of lightweight and crashworthiness.The key parts of the front car body play an important role in the safety performance of vehicle collision.This paper do some research based on a kind of pure electric vehicle carbon fiber body,as fowling:First of all,according to the ASTM standard test,specimens made by the CFRP material used for a vehicle body are prepared to do quasi-static tensile,compression and shear test.According to the data processing of materials performance curve,the material parameters are obtained.CFRP static tensile numerical simulation is carried out by LS-DYNA to check the failure mode and load displacement curve.Determining the specific parameters of the check CFRP prepares for later whole vehicle crash simulation.Secondly,in this paper,the frontal crash simulation of the body structure is carried out based on the C-NCAP regulations.The finite element model of the vehicle is established in the software Hypermesh,and the crashworthiness of the body structure is analyzed by the finite element analysis software LS-DYNA.The results basically meet the safety performance indicators,such as the invasion of the cockpit,the acceleration of the seat,the energy absorption of the front car body and the damage of the battery box.In the course of the collision,CFRP showed excellent toughness and energy absorption.After the removal of the external load,the deformation of the cabin cover was restored,and the energy absorption was about 41% of the front energy absorption,while performance of the main front-end energy absorbing components need to be improved.At last,considering the detailed analysis of the key components of the vehicle crashworthiness,the multi-objective optimization design of the anti-collision beam,the energy absorbing box and the longitudinal beam is presented in this paper.The Latin hypercube design method is selected to design three parts thickness,the vehicle collision model is calculated by LS-DYNA,kriging method is chosed to build agent model,genetic algorithm is used to find the optimal solution set,and we select the solution which can get maximum collision safety performance of the vehicle and reduce body weight.The results show that the CFRP material used in the body is provided with excellent toughness and energy absorption in the crash simulation.Automotive crashworthiness key components through optimization,the amount of invasion decreased by 7mm,the energy absorption increased by 10.37%,weight reduction by 3.85%.