胞孔构型对金属蜂窝动态力学性能的影响机理

采用ANSYS/LS-DYNA有限元研究了具有不同胞孔构型和排列方式的金属蜂窝材料在面内冲击荷载下的力学性能。在蜂窝的相对密度和冲击速度保持恒定的情况下，比较了它们的变形模式、动态承载力和能量吸收性能。结果表明，不同的胞孔构型导致在蜂窝压垮过程中胞壁的受力状态不同，从而影响蜂窝的宏观力学性能。根据胞壁的应力状态，可将蜂窝分为膜力主导蜂窝和弯曲主导蜂窝2大类。研究结果显示，蜂窝吸收的能量绝大部分转化为变形所需的内能，并且膜力主导蜂窝的内能占总能量的百分比更大。胞壁的屈曲导致膜力主导蜂窝的应力应变曲线呈现较大的波动。膜力主导蜂窝在变形过程中其胞壁会耗散更多的内能，从而比弯曲主导蜂窝具有更高的动态承载力和能量吸收能力。

Mechanism of cell configuration affecting dynamic mechanical properties of metal honeycombs

The in-plane dynamic behaviors of metal honeycombs filled by cells with various configurations and arrangements are studied by the finite element method using ANSYS/LS-DYNA.The deformation modes, crushing strength and energy-absorption ability are compared among these honeycombs while controlling their relative density and the impact velocity as uniform.It is shown that different cell configurations result in different stress states within the cell walls during the cells'collapse process, which thus influence the macroscopic mechanical properties of the honeycombs.According to the cell-walls'stress state, the involved honeycombs are divided into tow groups:membrane-dominated honeycombs and bending-dominated honeycombs.The results show that most of the absorbed energy of the honeycomb is transferred into the internal energy needed by the deformation.The percentage of the internal energy to the total absorbed energy is much more for the membrane-dominated honeycombs.The buckling of the cell-walls results in obvious oscillation in the stress-strain curves of the membrane-dominated honeycombs.The cell-walls in the membrane-dominated honeycombs will dissipate more internal energy during deformation, resulting in higher crushing strength and higher energy absorption ability than those of the bending-dominated ones.