Parameter analysis of damaged region for laminates with matrix defects

Considering the influence of bridge fibers, a representative volume element (RVE) with damaged regions of vanishing thickness is developed to study for estimation of laminates with transverse matrix cracks. For the open and closed cracks, the tensile force, the compressive force and the shear force are mainly studied by the stress-based variational approach with the pending partition loads at the statically indeterminate boundary, with considering not only three cases of the ideal transverse cracks, the smooth plane-surface open crack, the smooth plane-surface closed crack and the perfect meshing open crack, but also two cases of the non-ideal transverse cracks, the open cracks and closed cracks with the resistance resisting the relative sliding of crack surfaces. The expressions of the stress components in the RVE are obtained by means of assumption of the function of inter-laminar shear stresses. The governing equations are derived from the variational analysis based on the principle of minimum complementary energy. Both the effective mechanical properties and the distributions stresses of the damaged laminates with the ideal transverse cracks and those of the laminates with the non-ideal transverse cracks are estimated on the basis of the analysis of deformation on surface of the RVE.