Crashworthiness Research Of Energy Absorption Components Of Vehicle Body Based On Experimental Design

The vehicle crashworthiness has always been the key to the passive safety field.This paper employs experimental design and factor screening method for the energyabsorption property of the thin-walled bodywork under the impulsive load and thecrashworthiness under the front and side impact. This is helpful to improve thecrashworthiness of body structure.For the thin-walled structure, the peak collision force and the total absorbedenergy are two important indices of the crashworthiness. During the collision, the lesspeak collision force and the more total absorbed energy are expected based on thephysical injury biomechanics. However, the current study shows that it is difficult tocoordinate these two indices without changing the original structure. In order to solvethe conflict between the peak collision force and the total energy absorption duringcollision, we analyzed the thickness of the thin-walled column made of lasertailor-welded blank and the yield strength of the thin-walled column out of thethermoforming gradient strength plate. The restricted two-factor experimental design,approximate model and NSGA-II optimization algorithm are adopted. The optimalthickness and yield strength of these two columns are obtained respectively. Theresults indicate that the optimization of thickness and yield strength and the use ofthese two new plates can commendably solve the conflict between the peak collisionforce and the total energy absorption.In addition, this paper employs three-level unreplicated saturated factorial designfor the crashworthiness optimization under the frontal and side impact. The givenanalysis method is used to screen significant factor having great effect on frontal andside impact from13parts according to the crashworthiness index. The selectedsignificant factors are treated as variables of multivariable crashworthinessoptimization. In the frontal impact, the improvement of the final model compared withthe initial model are that the acceleration of the bottom of B pillar is reduced by5.465%, the internal energy absorbed by the vehicle body is increased by0.359%andthe total energy of13parts was increased by0.153%. In the side impact, theimprovement are that the maximum intrusion of B pillar, the maximum velocity of theB pillar’s waist line, the first peak of the acceleration at the bottom of thenon-collision side B pillar and the total mass of5parts are reduced by19.129%, 10.373%,4.714%and12.344%, respectively.The results show that the crashworthiness optimization can improve the vehicle’scrashworthiness and have certain reference to the real car design.