Analysis And Optimization Of Side Crashworthiness Of Auto Body Based On Simplified Model

As rising car ownership in China, the traffic safety situation has become even moresevere, caused a great threat to the personal safety of the citizens. In view of statistical data oftraffic accidents in China in recent years, the rate of deaths and injuries caused by side impactaccident only second to frontal collision, mainly due to the body side main bearing memberstiffness is relatively weak and lack of absorbers, thus the vehicle occupant injuries are oftenmore severe than other forms of accident. Therefore, how to further improve body sidecrashworthiness has become the focus and difficulty of the body security development.In this paper, simplified models were introduced to improve side crashworthiness, thesimplify model can be calculated quickly and easily modified. Several simplified models werelisted that studied at home and abroad. By comparing the advantages and disadvantages ofeach model, the author selected out two models of different levels of simplification. Twosimplified models were derived from the full vehicle finite element model, before theapplication of the simplified model, a side crash test was carried out on the full vehicle modeland the model was verified reliability by comparison with the results of real vehicle test. Thefirst established simplified model was the lateral sub-structure model, each part of the modelare derived from the full vehicle, by omitting the parts that did not directly involved in thedeformation and energy absorption or only occurred rigidity lateral displacement in process ofside collision. The lateral sub-structure simplified model was verified reliable by carrying outthe same crash test as the full vehicle did, the robustness of loading boundary conditions alsobe verified. On basis of this, thermal forming method of high strength steel technology wasused to strengthen the outer plate of the B column for stiffness gradient optimization, in orderto improve safety performance of body-side. Another simplified model is a kind of newbeam-shell mixed element model, which was built by further simplifying substructure model.The modeling process and key technology were introduced. Through the side impact testunder the same conditions as full vehicle model, this type of simplified model was provedreliable, the causes of model-creation error also analyzed. Finally the paper discussed usingthe beam-shell model for side crashworthiness optimization by using the direct optimizationmethod, and the results were tested by full vehicle side crash test.The results show that: the sub-structure simplified model remains critical bearing forceparts after greatly simplifying the full vehicle structure, this method could balance thecontradiction between calculation efficiency and accuracy and is a simple and practical method. The beam shell simplified model accuracy was not high, but the model can becalculated quickly and easy to modify to meet the needs of the body conceptual design stage.