多孔泡沫牺牲层的动态压溃及缓冲吸能机理研究

本文对强动载荷下多孔泡沫牺牲层的动态压溃行为及缓冲吸能机理进行了研究. 基于刚性-理想塑性-锁定(R-PP-L)及刚性-塑性硬化(R-PH)两类多孔泡沫材料本构, 建立了强动载荷下多孔泡沫牺牲层动态响应的理论分析模型, 分析了一维冲击波在多孔泡沫牺牲层中的传播规律; 利用Voronoi方法建立了多孔泡沫牺牲层的二维细观有限元模型, 获得了冲击载荷下多孔泡沫牺牲层的变形模式和动态响应曲线, 讨论了多孔泡沫材料的层间界面效应对多孔泡沫牺牲层缓冲吸能的影响. 研究结果表明, 考虑多孔泡沫材料塑性硬化影响的理论分析模型能够预测入射波在远端的反射及对多孔泡沫牺牲层的二次压缩过程和端部应力增强现象; 相比较存在界面的多孔泡沫牺牲层, 连续设计的多孔泡沫牺牲层可增强其缓冲吸能能力, 但在界面处增加设计刚性面板则能够降低界面胞元不完整对缓冲吸能的影响; 相同冲量载荷下, 端部应力峰值随冲击能量增大而增大, 而端部冲击波的反射可能是端部应力增强的主要诱因. 

RESEARCH ON DYNAMIC CRUSHING AND MECHANISM OF MITIGATION AND ENERGY ABSORPTION OF CELLULAR SACRIFICIAL LAYERS

In this paper, the dynamic crushing behavior and the mechanism of mitigation and energy absorption of the cellular sacrificial layers subjected to the intensive dynamic loading are investigated theoretically and numerically. Based on the rigid, perfectly plastic, locking (R-PP-L) and the rigid, plastic hardening (R-PH) constitutive models of the cellular materials, a theoretical model of the dynamic response of the cellular sacrificial layers subjected to the intensive dynamic loading is developed. The one-dimensional shock wave propagation in the cellular sacrificial layers is analyzed further. Finite element model is established by employing the Voronoi method and the numerical simulations are carried out to obtain the deformation modes and the response curves whilst the effect of interface on the mitigation and the energy absorption of the cellular sacrificial layers is discussed in detail. It is shown that the theoretical model considering the plastic hardening of cellular materials (R-PH model) can effectively predict the reflection of incident wave at the distal end and the secondary compression process of the cellular sacrificial layers as well as the enhancement phenomenon of the end stress than the R-PP-L model. Comparisons between the continuous and discontinuous interface models demonstrate that the continuous design of the cellular sacrificial layers can enhance the mitigation and the energy absorption while the interfaces separated by the rigid plates can decrease the effect of the incompleteness of interface cells. The peak stresses at the ends subjected to the same momentum increase with the increase of impact energy. It is possible that the reflection of the shock wave at the ends results in the stress enhancement at the ends.