正方形蜂窝芯材共面冲击力学性能

In-plane Dynamics of Square Honeycomb Cores

目的研究正方形蜂窝芯材在共面冲击载荷作用下的力学行为。方法借助于有限元软件ANSYS/LSDYNA,建立了相应基于单元阵列的有限元模拟和分析方法。结果随着冲击速度的增加,正方形蜂窝表现为不同的变形模式,其冲击响应的力-位移曲线包含了具有明显不同特征的4个阶段,对于给定结构参数的正方形蜂窝样品,在不同冲击速度下会呈现出不同的变形模式。计算出了不同冲击速度下不同壁厚边长比的正方形蜂窝芯材的动态峰应力。结论正方形蜂窝芯材的动态峰应力,是其静态峰应力和因惯量引起的峰应力增量之和;静态峰应力与正方形蜂窝芯材的相对密度成正比,峰应力增量与冲击速度的平方成正比,而相对密度又取决于壁厚边长比。最后拟合得到了动态峰应力关于壁厚边长比和冲击速度的经验公式。

Objective To study the mechanical behaviors of square honeycombs cores under the in-plane dynamic impact loadings. Methods Corresponding finite element simulation and analysis methodology based on cell array was established using the ANSYS/LSDYNA tool. Results With the increasing impact velocities, different deformation modes were observed. The force-displacement curves included four regimes with distinct characteristics. Different deformation modes were observed for a specimen with given configuration parameters at different impact velocities. The dynamic plateau stresses were calculated for the square honeycombs cores with different t/l ratios at different in- plane impact velocities. Conclusion The dynamic plateau stress was the sum of the static plateau stress and the dynamic enhancement due to the inertia effect. The static plateau stress was proportional to the relative density of square honeycombs cores. The dynamic enhancement stress was proportional to the square of impact velocity and the relation coefficient depended on the t/l ratios. The empirical formula of dynamic plateau stress in terms of ill ratio and impact velocity was given.