The Interlaminar Stresses of Symmetric Composite Laminates

Three-dimensional finite element interlaminar stress solutions of composite laminates with resin layers under uniform axial strain are presented. Their three-dimensional distributions are plotted. In the cross-ply laminate, interlaminar normal and shear stresses are shown to be of free-edge effect. But shear stresses are found to be significantly reduced in the free-edge region, which show some conformity to the boundary stress conditions. In the angle-ply laminate, the stress distributions all vary significantly along both extension and width directions. There exists free-edge effects and end-edge effects in this case; however, the peaky interlaminar stresses are not exactly at the edges, but are near the edge regions.