胞元结构准静态压缩力学行为及吸能特性研究

Quasi-static compressive mechanical behavior and energy absorption characteristics of cell structure

为探究结构构型和规格参数对胞元结构综合力学特性的影响,设计了7种体积相等、结构构型不同的胞元结构,开展了准静态压缩试验,得到了各胞元结构的变形破坏过程和应力应变关系,分析了胞元构型和壁厚变化对结构承载能力及能量吸收性能的影响,结果表明:内凹鼓形、内凹六边形、内凹弧形胞元结构均呈现出宏观负泊松比特性,外凸六边形、外凸鼓形、正方形胞元结构呈现出宏观正泊松比特性,外凸弧形胞元结构呈现出近似零泊松比特性;胞元结构的直立壁面和曲面(折线面)共同承担压缩载荷,直立壁面主要发生失稳变形,曲面(折线面)主要发生弯曲外张变形或弯曲回缩变形,直立壁面的失稳临界载荷和屈曲模式对结构承载力和平台应力起主导作用;在各个宏观正泊松比胞元中,外凸六边形胞元的结构承载能力较强,外凸鼓形胞元的结构吸能特性较好,在各个宏观负泊松比胞元中,内凹弧形胞元的结构承载能力和结构吸能特性均较好。

Here,to explore effects of structural configuration and specification parameters on comprehensive mechanical properties of cell structure,7 cell structures with equal volumes and different structural configurations were designed,and quasi-static compression tests were conducted on them.Deformation/failure processes and stress-strain relation of each cell structure were obtained.Effects of cell configuration and wall thickness on load-bearing capacity and energy absorption performance of the whole structure were analyzed.The results showed that concave drum,concave hexagon and concave arc cell structures have macro negative Poisson ratio characteristics,external convex hexagon,external convex drum and square cell structures have macro positive Poisson ratio characteristics,and external convex arc cell structure has approximate zero Poisson ratio characteristics;vertical wall and curved surface including fold line surface of cell structure bear compressive load together;vertical wall mainly has instability deformation,and curved surface including fold line surface mainly has bending external tension deformation or bending retraction one;the instability critical load and buckling mode of vertical wall play a leading role in structural load-bearing capacity and platform stress;in macro positive Poisson’s ratio cells,external convex hexagonal cell has stronger structural load-bearing capacity,external convex drum cell has better structural energy absorption performance;in macro negative Poisson’s ratio cells,concave arc cell has better structural load-bearing capacity and structural energy absorption performance.