部分充液多胞元结构的面内动态力学特性研究

为探究部分充液多胞元结构的抗冲击防护性能，结合充液内凹胞元的落锤冲击试验，建立了充液内凹胞元、部分充液内凹多胞元结构的冲击动态特性二维FEM数值分析，计算得到了部分充液内凹多胞元结构的变形破坏模式，讨论了不同冲击速度下部分充液内凹多胞元结构的动力学响应特性。结果表明:在充液胞元破损后，水介质会流入相邻未充液胞元，形成二次鼓胀吸能效应，从而有效提高结构壁面的变形吸能水平；结构中的充液区域和未充液区域的变形破坏模式分别为鼓胀拉伸和屈曲弯折；随着冲击速度的提高，结构的单位体积应变能以及对初始冲击载荷的削弱作用均得到增强。横向充液方式可以等效为变刚度弹簧的串联布置，该方式仅影响结构的局部刚度，纵向充液方式可以等效为多层变刚度弹簧的并联布置，该方式会影响结构的整体刚度；充液区域与未充液区域的等效刚度呈动态变化，结构变形模式由各区域实时的等效刚度决定。当载荷冲击速度较高时，横向和纵向部分充液内凹多胞元结构对初始冲击载荷的削弱能力均优于未充液内凹多胞元结构。

In-plane dynamic mechanical properties of partially liquid filled multicell structure

In order to investigate the impact protection performance of partially liquid filled multicell structure, the two-dimensional FEM numerical analysis of the impact dynamic characteristics of liquid filled inner concave cell structure, unfilled inner concave cell structure, partially liquid filled inner concave multicell structure and unfilled inner concave multicell structure was established by combining the drop hammer impact test of liquid filled and unfilled inner concave cell structure. The deformation/failure mode of partially liquid filled inner concave multicell structure was obtained, and the dynamic response characteristics and energy absorption characteristics of partially liquid filled inner concave multicell structures at different impact velocities were discussed by using the initial load weakening factor and the strain energy per unit volume, respectively. The results show that after the breakage of the liquid filled cell, the water medium will flow into the adjacent unfilled cell, developing a secondary bulging energy absorption effect, thus effectively increasing the deformation energy absorption level of the structure wall; the deformation damage modes of the liquid filled and unfilled regions of the structure are bulging tension and flexural bending, respectively; the strain energy per unit volume of the structure and the weakening effect on the initial impact load are enhanced with the increase of the impact velocity. The transverse filling method can be equated with tandem arrangement of variable stiffness springs, which only affects the local stiffness of the structure. And the longitudinal filling method can be equated with a parallel arrangement of multiple layers of variable stiffness springs, which affects the overall stiffness of the structure; the equivalent stiffness of the filled and unfilled regions changes dynamically, and the deformation mode of the structure is determined by the equivalent stiffness of each region in real time. When the load impact velocity is high, both transverse and longitudinal partially liquid filled inner concave multicell structures are superior to the unfilled inner concave multicell structure in weakening the initial impact load.