新型DKT组合薄壳单元及对侧翻一步碰撞算法的改进

New Type of DKT Combined Thin Shell Element and the Improvement of the One-step Collision Algorithm for Rollover

针对客车侧翻有限元分析过程中部分单元翘曲的问题,首先对四节点薄壳单元进行翘曲修正改进。基于改进后的四节点薄壳单元和全量应变理论,将DKT四节点薄板单元和传统四节点等参膜单元组合,构造一种新型四节点DKT组合薄壳单元。接着,用该单元替代客车侧翻一步碰撞初始算法的四节点Mindlin壳单元,并对初始算法进行改进。最后,应用改进算法对某12 m公路客车典型车身段模型进行侧翻模拟,并与初始算法、LS-DYNA和实车侧翻试验结果对比,验证了所提出的新型四节点DKT组合薄壳单元在实际工程应用的有效性。

Aiming at the warping problem of some elements in the finite element analysis of bus rollover,the four-node thin shell element is improved with warp correction first.Based on the improved four-node thin shell element and the total strain theory,a new type of four-node DKT combined thin shell element is constructed by combining the DKT four-node thin plate element with the traditional four-node isoparametric membrane element.Then the four-node Mindlin shell element used in the one-step collision initial algorithm for bus rollover is replaced by the new DKT element,with the initial algorithm improved.Finally,the improved algorithm is applied to the rollover simulation of the typical body section model for a 12 m highway bus and its result is compared with those of initial algorithm,LS-DYNA and real bus rollover test,verifying the effectiveness of the constructed new type of four-node DKT combined thin shell element in practical engineering application.