1991 年 39 巻 451 号 p. 410-418
The present paper deals with the failure analyses of symmetric angle-ply laminated composites with different number of stacking layers. The problem is investigated under a uniform axial extension through the application of nonlinear constitutive equations, which are based on the three-dimensional Ramberg-Osgood formulas. A quasi-three-dimensional finite element method with a four-node rectangular element is utilized in analyses. The post-failure state is analyzed by taking into account the change of material properties due to initial failure evaluated by the maximum stress criterion. Numerical calculation is made for [45°4/-45°4]s (four layers) and [45°/-45°/45°/-45°]s (eight layers) CFRP symmetric angle-ply laminates. The ultimate strengths predicted by the present method are in good agreement with the experimental results for 45° four- and eight-layered CFRP laminates. Basing upon the propagation of the failure, we propose the failure modes of the four- and eight-layered laminates. The proposed failure modes agree with the experimental failure modes. We also investigate the strength of laminates versus angleply orientations.