受弯脱层层板的局部失稳临界载荷的有限元分析

A FEM TO PREDICT THE CRITICAL LOAD OF INSTABILITY ANALYSIS OF DELAMNATION IN LAMINATES UNDER BENDING LOAD

含脱层的复合材料层板承受弯曲载荷作用会产生跳跃失稳,还常常引起脱层扩展,从而导致结构失效。本文用基于一阶剪切层板理论的几何非线性有限单元法分析了受弯曲载荷作用下含脱层层极的失稳的临界载荷。本文指出分叉失稳产生了跳跃失稳,而该跳跃失稳与浅圆拱或薄圆柱壳受向心压力作用下的跳跃失稳不同,在整体平衡路径上没有一个极限点。本文对临界载荷的计算结果比使用能量准则的结果要小,文中给出了原因。

Local buckling of delaminated laminates subjected to bending loads frequently bring about snap-through buckling, which often causes delamination growth and leads the structure to failure. In this paper, an analysis is made to predict the critical load of instability of the delaminated laminates by the use of a geometrically nonlinear one-dimensional finite element method. It is found that the bifurcation instability produces snap buckling without a limit point on the equilibrium path, which is quite different from the snap buckling of a shallow thin cylindrical shell under concentrated load. However, the results offer lower loads of instbility than that when the energy criterion is used. In the paper, explanation is also given.