中文摘要：

利用显式动力有限元方法数值研究了具有密度梯度六边形蜂窝材料的面内冲击动力学性能。根据功能梯度材料的概念，首先建立了具有密度梯度的蜂窝材料模型。基于此模型，具体讨论了密度梯度和冲击速度对六边形蜂窝材料变形模式和能量吸收性能的影响。研究结果表明，通过恰当地选择蜂窝材料的密度梯度，初始应力峰值明显减小，材料的能量吸收能力能够有效地得到控制。此结论为实现多胞材料动力学性能的多目标优化设计提供了新的设计思路。

英文摘要：

The in-plane dynamic crushing of hexagonal honeycombs with density gradients is numerically studied by using explicit dynamic finite element method. Based on the concept of functionally graded materials, the density graded honeycomb mode is firstly established. And then the effects of density gradient and impact velocity on the deformation modes and the energy absorption capacities of hexagonal honeycombs are discussed in detail. Research results show that through the proper choice of the density gradient of honeycombs, the initial stress peak could be reduced significantly, and the energy absorption could be controlled effectively. The results will provide some useful guides in the multi-objective optimization design of impact dynamic properties of cellular materials.