三维编织复合材料圆柱壳的扭转后屈曲分析

Postbuckling Analysis of Three Dimensional Braided Composite Cylindrical Shells under Torsion

随着三维编织复合材料应用的日益广泛,且由于三维编织复合材料的优异性能是与细观结构密切相关的,深入研究其细观结构显得尤为重要。本文通过研究三维圆型编织中所形成的空间纱线交织结构的特征,给出改进的三胞结构单胞模型,通过单胞的组装和变换,得到编织预制件的整体力学性能模型。基于Reddy高阶剪切变形理论导得广义Kármán型大挠度方程,计及边界层效应,采用奇异摄动法,考虑非线性前屈曲、大挠度和初始几何缺陷的影响,给出三维四向编织复合材料圆柱壳在扭转载荷作用下的严格满足边界条件的大挠度渐近解,讨论了纤维体积含量、编织角和几何参数等因素对圆柱壳屈曲和后屈曲行为的影响。

In the three dimensional braiding procedure, the braiding yarn is tended to move along the direction of its carrier movement. A 3-cell analytical model was used to estimate the mechanical properties and elastic constants and to analyze effects of the three dimensional braiding parameters on the properties. Postbuckling analysis was presented for a three dimensional braided composite cylindrical shell of finite length under torsion. The governing equations were based on Reddy＇s higher order shear deformation shell theory with yon Karman-Donnell type of kinematic nonlinearity. The influence played by the geometrical parameters of cylindrical shell and the physical parameters of materials on the postbuckling behavior of three dimensional braided composite shell was investigated. It is noticed that the postbuckling of shells is highly dependent on structural characteristics, and it is concluded that the fiber volume fraction, and the shell geometric parameter have a significant effect on the buckling load and postbuckling behavior of braided composite cylindrical shells.