A method of strain and stress analysis of composites for nonlinear strain distribution case

In this study, a method of strain and stress analysis is developed to determine the stress and strain fields in fibers and matrix of a laminated composite for the cases of nonlinear strain and stress distributions with high gradients. The strain values calculated by using a classical method are considered as input, and the strain fields at each layer are determined. These strain fields are then used as input to express the strains in fibers and matrix. In these processes the heterogeneity effects, which are caused by the existence of different materials in a composite, are taken into account. By the summation of input strains and the heterogeneity strains, the strains in the fibers and the matrix are calculated. By using the fiber and matrix strains in constitutive equations the stresses in fibers and matrix are obtained. The non-classical method is applied to a sample problem and numerical results are presented as well as a comparison of the layer stresses with the results from MSC/Nastran finite element software composite material solution.