Predictions of deflection and first-ply failure load of thin laminated composite plates via the finite element approach

Abstract

A nonlinear finite element method, which is based on the von Karman-Mindlin plate theory and the principle of minimum total potential energy, is used to study the deformation and first-ply failure of thin laminated composite plates. The load displacement curves of a number of laminated composite plates are determined using the proposed finite element method. Stresses obtained fr'om the linear and nonlinear finite element analyses are used to determine, respectively, the linear and nonlinear first-ply failure loads of the laminated plates based on several phenomenological failure criteria. The accuracy of the finite element results is then verified by comparison with the available experimental data. It has been found that good agreement between the finite element and experimental load strain curves before first-ply failure is observed. If the reduction in plate stiffness induced by failure of plies is taken into account in the finite element model, close agreement between finite element and experimental load displacement curves from first-ply failure up to total failure may be obtained. Regarding the prediction of the first-ply failure load, it has been found that some of the phenomenological failure criteria may yield results of consistent accuracy for the laminated composite plates under consideration. Nevertheless, accurate prediction of the failure process after first-ply failure is still intractable. Hence, for reliability assurance further research on failure analysis of laminated composite plates subject to transverse loading is needed.