薄壁钢结构碰撞性能仿真中材料模型研究

On Material Model for Thin-walled Sheet Metal Crashworthi-ness Simulation

讨论了动态弹塑性理论中的应变率相关材料本构关系及其在数值计算中的简化模型，研究了计入应变率、不计入应变率的双线性弹塑性材料摸型和３参数Ｂａｒｌａｔ材料模型在闭口帽型薄壁梁在轴向碰撞载荷下的屈曲模态中对数值计算结果的影响，并和实验数据进行了比较，结果显示在碰撞研究中应变率对结构碰撞特性有着重要的影响。仿真结果表明应变率是薄壁钢材料构件静动态实验结果差异的主要因素，并由此给出了应变率影响的敏感性系数。研究结果为利用有限元方法进行碰撞结构设计提供了依据。

Strain-rate sensitive constitution equation and its simplified model in numerical simualation is disscussed in this paper. Cowper Symonds strain rate model,rate effects non-con sidered bilinear kinematic model and 3-parameter Barlat model are applied to a close-hated section beam under axial crashing load model. Strain rate influence index is found by comparing numerical simulation results and experimantal datum. Datailed analysis shows the strain rate at plastic hinges is high and in the region of strain rate sensitive. The results show strain rate is vi tal to structure crashworthiness analysis and is the main reason for the difference between quasi-static and dynamic crash test.