基于Johnson-cook本构模型的EPE包装跌落冲击模拟

目的将聚乙烯泡沫塑料在动态压缩试验下得到的力学性能引入有限元中,创建材料模型,并应用于跌落冲击仿真分析,以提高仿真的精确度。方法通过聚乙烯泡沫塑料在不同速率下的压缩试验,得到真实的应力-应变曲线,并基于Johnson-cook本构模型在有限元中建立EPE的材料模型。最后用AnsysWorkbench中的LS-DYNA模块对聚乙烯泡沫缓冲包装的跌落过程进行仿真分析,用LS-PREPOST软件进行后处理。在此基础上,对比分析仿真结果和实验结果。结果仿真结果的误差分别为0.85%,1.6%,2.97%,与实验结果基本一致。结论基于Johnson-cook本构模型构建的聚乙烯泡沫塑料有限元材料模型能有效提高低速冲击的仿真精度,为非线性材料和应变率敏感材料的有限元动态冲击分析提供了参考。

EPE Package Drop Impact Simulation Based on Johnson-cook Constitutive Model

The work aims to introduce the mechanical properties of polyethylene foams obtained by dynamic compression experiments into the finite element to create material model and apply them to drop impact simulation analysis to improve the accuracy of the simulation. The actual stress-strain curves were obtained through compression experiments at different rates of polyethylene foam, and a material model of EPE was established in finite element based on the Johnson-cook constitutive model. Finally, the LS-DYNA module in the Ansys Workbench was used to simulate the drop process of the polyethylene foam cushioning package and LS-PREPOST software was used for post-processing. On this basis, the simulation results and experimental results were compared and analyzed. The errors of simulation results were respectively 0.85%, 1.6% and 2.97%, which were basically consistent with the experimental results. The finite element material model of polyethylene foam constructed based on the Johnson-cook constitutive model can effectively improve the simulation accuracy of low-velocity impact, which provides a reference value for the finite element dynamic impact analysis of nonlinear materials and strain rate sensitive materials.