Post-buckling analysis of delaminated composite laminates with multiple through-the-width delaminations using a novel layerwise theory

• A novel layerwise theory is developed to analyze the post-buckling behavior of the delaminated composite laminates with multiple delaminations.
• The proposed method is capable to model the local buckling of the delaminated sublaminate and the mixed and global buckling modes of the delaminated plates.
• The presented method is suitable to apply for thick delaminated plates.
• The number of DOF in this model is markedly less than those used in FEM.
• The contact among sublaminates is also handled and the Penalty method is employed in order to prevent penetration violation.

A novel layerwise theory based on the first order shear deformation theory (FSDT) has been proposed to evaluate the buckling and post-buckling behavior of delaminated composite plates with multiple through-the-width delaminations. The Rayleigh–Ritz Method has been adopted and displacement fields are obtained by incorporating simple and complete polynomial series which result in much less computational cost. The proposed layerwise theory provides a more realistic description of the kinematics of composite laminates when compared to Equivalent Single Layer theories. Both local buckling of the delaminated sublaminates and global buckling of the whole plate can be handled. The method is capable of predicting response of thick delaminated composite plates. Presence of multiple delaminations can also be handled. In order to prevent unacceptable penetration, contact constraints are imposed on the delaminated area. The three dimensional finite element analysis is performed using ANSYS5.4 commercial software. The results show a very good agreement with those obtained by the analytical Model.