结构参数对自相似多级蜂窝力学性能的影响

对蜂窝的代表性体积单元(RVE)研究发现,相比于均匀化边界条件,周期性边界条件能更好地预测蜂窝的等效力学性能。基于周期性边界条件,对自相似多级蜂窝进行面内不同方向的拉伸模拟,重点分析了蜂窝孔隙率与多级长度比对拉伸性能的影响。结果表明:自相似多级蜂窝在拉伸过程中会呈现面内各向异性,沿扶手椅方向拉伸时,会在节点六边形的水平连接边处发生断裂;沿锯齿形方向拉伸时,当节点六边形的边长大于壁厚和节点六边形的连接斜边的边长较长的情况下,蜂窝会出现两次拉伸破坏,分别在节点六边形边与节点六边形的连接斜边处,而在其他情况下,则只会在节点六边形连接斜边处发生一次破坏。并且自相似多级蜂窝随着孔隙率或长度比的增大,蜂窝拉伸强度呈现减小的趋势。

Influence of structure parameters on mechanical properties of self-similar hierarchical honeycombs

The present study on the representative volume element (RVE)of honeycomb structures shows that, by compared with the homogeneous boundary conditions (HBCs),a more accurate result is obtained by using the periodic boundary conditions (PBCs).Based on the RVE with the PBCs,tensile tests of the self-similar hierarchical honeycombs (SSHHs)along the two in-plane directions were simulated.The effects of the porosity and the hierar-chical length ratio were especially examined.The numerical results show that a large in-plane anisotropy in the SSHHs is observed.The SSHHs fails at the horizontal-links when it is subjected to a tension along the armchair di-rection.But when it is subjected to a tension along the zigzag direction,in case of the SSHHs with the edge of node-hexagon greater than the wall thickness and a long length of the hypotenuse-links,it will break down twice respec-tively at the node-hexagon and the hypotenuse-links,otherwise it breaks down once at the hypotenuse-links.It also can be seen that the tensile strength decreases with the increase of either the porosity or the hierarchical length ratio.