NONLINEAR FINITE ELEMENT ANALYSIS OF INTERLAMINAR STESSES IN COMPOSITE LAMINATES

In order to predict and suppress delamination in composite laminates,a comprehensive knowledge about the mechanism of interlaminar stresses in compasite laminates is necessary. In the present paper, a nonlinear quasi-three-dimensional finite element procedure is presented,in which a mpdified Elahn-Tsai nonliner constitutive equation is used.The results for an angle-ply ±45_s and symmetric cross-ply laminates are presented. The lamina properties in the laminates have obvious nonlinearity in shear deformation and a little in transverse tension.Emphasis is placed on assessing the stress behavior in the regions close to ply-interface and exposed free edge.Compared with elastic results,the solutions indicate that material nonlinearities can cause the decrease in interla minar shear stresses to a certain degree,but they have little effect on the distributions of interlaminar normal stress.