Optimization On Anti-impact Performance Of Vehicle Component Based On Side Crash

With the development of light-weight technology, vehicle component that has tailored properties has drawn great attention. For steel material applied on vehicle, tailor wielded blank(TWB), tailor rolled blank(TRB) are usually used to achieve tailored properties. Besides, different cooling method is also broadly used to obtain component with tailored strength. However, what kind of tailored properties help to improve safety is still a key problem. Usually, manufactures will develop a product based on test and experience but researchers may pay more attention to theoretical study so that it's difficult to apply the outcome in real production. Therefore, based on this problem, anti-impact performance of vehicle component with tailored properties was studied.Firstly, large deformation dynamic experiment was carried out to verify the correctness of modeling method and material parameters. The results shows that, the trend of deformation type and force-displacement curve are basically the same which testify that modeling method and material parameters are reliable. However, there is still problem that under the same condition repeatability of crushing test is not good. Deformation and damage mode vary from each other.Secondly, original whole car side impact model was simplified and its reliability was also testified. Because of the importance of B-pillar during side impact, two standards were selected as evaluation of B-pillar performance and they are maximum intrusion(Dmax), energy absorption(EA). Next, B-pillar was divided into 3 parts according to the relationship between Dmax and sever injury rate. B-pillar structure was further simplified to improve its light-weight design limit. Effect of transition zone in tailored property B-pillar(TPB B-pillar) and tailored rolled B-pillar(TRB B-pillar) was discussed. Main part of this section is the study of B-pillar with 3 partition. Result shows that, as for TPB B-pillar, from the outcome of 64cases, it reveals that each part has different influence during impact, especially the middle part. For TRB B-pillar, the 27 simulation results indicate that the thickness of middle part has major effect to the anti-impact performance.Finally, numerical model was fitted based on simulation data. One optimization method was selected to solve the optimal problem for TPB and TRB B-pillar respectively and the result was compared with standard case. Radial basis function (RBF) was adopted to fit the simulation data of TPB and TRB B-pillar. Then, non-dominated sorting multi-objective optimization algorithm with elitist strategy (NSGAII) method was applied to generate optimal case for these two models. The result shows that, for TPB B-pillar, the optimal case was actual combined into 2 parts instead of 3 parts. That is, top and middle part share the same strength which is higher than the strength of bottom part. This kind of distribution can provide better performance and is easily produced. For TRB B-pillar the final optimal case indicates that thickness of middle part should be larger than top and bottom part. The maximum thickness difference is 1.25mm which is acceptable according to actual manufacturing. At last, comparison between standard case and final optimal cases of TPB,TRB B-pillars, it shows that the optimal cases all behave better than standard case and in addition optimal case of TRB is more competitive integrally.