Numerical analysis of free corner effects in angle-ply composite laminates based on global-local method

The main purpose of this paper is modeling of the free corner effect of cross-ply and angle-ply graphite/epoxy composite laminates using finite element method based on global-local method. The global area is modeled by first order shear deformation theory and the local area, in the free corner vicinity, is modeled by the Reddy's layer-wise theory. Using this method provides the possibility of analysis of thick angle-ply and cross-ply laminates. The cross-ply and angle-ply laminates are subjected to uniform thermal and extension loading, respectively and the effects of the free edge and free corner interlaminar stresses are investigated. The presented results verification is performed via available results in the previous studies which show good agreement. The present study results show that when the cross-ply laminate is subjected to thermal loading, the interlaminar stresses distribution is uniform in both length and width of the laminate. However, for the uni-axial extension loading, the interlaminar stresses possess different distribution in the two directions of the laminate. Also, results demonstrate that in angle-ply laminates under extension loading, the free corner effect increases by increasing fiber angle and the maximum interlaminar stresses occur in 30 degree plies in the free corner vicinity. Moreover, results prove that the effects of the free edge and the free corner are almost similar in layers with fiber angle less than 30 degrees. Parametric study on the thickness and stacking of the laminate layers display that both parameters have a significant influence on the interlamianar stresses at the free corner.