惯性对多孔金属材料动态力学行为的影响

 对泡沫金属材料的力学性能已经进行了十分广泛的研究，但在对泡沫金属的应变率效应和惯性效应的研究中，尚存在一些矛盾的结论。为进一步认清惯性在多孔金属动态响应中的作用，用有限元计算方法模拟了二维Voronoi蜂窝的动态压缩行为，得到了不同速度下Voronoi蜂窝的3种变形模式。通过改变基体材料的密度和冲击速度进行“数值实验”，得到了相应“试件”的由冲击面和支撑面得到的宏观平均应力应变曲线和平台应力。根据数值模拟的结果，着重分析了惯性效应的影响。研究发现，惯性并不影响蜂窝的应力应变曲线，但它导致试件中宏观变形不均匀，是平台应力提高的主要原因。

Effect of Inertia on the Dynamic Behavior of Cellular Metal

Although the mechanical property of metal foams has been widely studied, there are some conflicting conclusions on the strain-rate effect and the inertia effect of metallic foams. For a deep understanding of the role of inertia in the dynamic response of cellular metals, finite element method is used to study the dynamic compression of 2D Voronoi honeycombs. Three deformation modes are formulated. "Numerical experiments" are conducted by changing the density of wall material and the impact velocity. Corresponding macroscopically-averaged stress-strain curves measured on the impact surface and support surface and the plateau stress of the "specimens" are obtained. According to the simulation results, the influence of inertia is analyzed. It is found that the inertia of the honeycomb has no effect on the stress-strain curve as the macroscopic deformation is homogeneous. However, the inertia effect will result in nonuniform deformation as the impact velocity is high, and thus the plateau stress is obviously increased.