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Progressive Failure Analysis of Laminated Unstiffened and Stiffened Composite Panels

Progressive failure analysis of laminated unstiffened and stiffened composite panels has been carried out in the present investigation. The laminated panels under transverse static loadings in the linear elastic range have been investigated using the finite element method. In the finite element analysis of stiffened panels, eight-noded isoparametric quadratic elements in association with the three-noded curved beam elements have been considered and the first-order shear deformation theory is utilized. An iterative method has been adopted using the various failure theories to predict the first-ply failure load. After the first-ply failure, the stiffness of the failed lamina has been totally discarded from the laminate and the remaining laminae were considered for further analysis. The progressive failure analysis using the Tsai-Wu failure criterion has been implemented into a general-purpose finite element code to predict the failure loading from the initial to the final stage.