Post-failure analysis of composite laminated structure

Abstract

A method for the post-failure analysis of the laminated composite was presented. The Failure of the laminated composite was classified into the matrix failure and the fiber failure. Macroscopic failure models for these failure were implemented to a finite element method for the desciption of the behavior of laminated composite after first ply failure. In the finite element analysis, material nonlinearity induced from the nature of damaged ply constitutive relation was accounted for by the formulation. The stiffness change of the matrix cracked lamina was evaluated by using of shear lag analysis, and the behavior of fiber directional failure was modeled with the conception of fiber bundle failure. Shear lag method was extended to describe the matrix crack developed by the in-plane shear deformation. The validity of the stiffness reduction model was confirmed by comparing with the result of finite element analysis for the unit matrix crack. Present analysis showed better agreement with experimental results than previous simple analysis for the stress-strain relation of flat specimen. The damage accumulation of the composite laminate with a hole was analyzed with the presented method. The effect of the mesh size and the size of the load increment on the ultimate failure load were investigated to guarantee the consistency of the analysis. The damage progression of the laminate subject to tensile and compessive loading was compared. It has shown that the matrix crack could be generated by the shear deformation in the laminate with a hole subject to compressive loading. The type and the size of damage, the stress state after matrix failure, and the matrix crack density were referred in the analysis. Results of the present analysis were compared with those of other analysis methord. Besides that the present model has used more accurate stiffness of the matrix cracked ply, the present analysis has predicted the stress state and the matrix crack density. The present met...