Non-linear bending analysis of composite laminated plates using a refined first-order theory

A refilled single-layer model of geometrically non-linear composite laminates is presented using a mixed variational approach. The present model accounts for Reissner-Mindlin's assumptions on displacement and continuous stress distributions at the layer interfaces. Therefore, the present first-order plate theory recovers the actual interlaminar stress state without losing its simplicity and leads to a consistency with the theory of elasticity. Furthermore, the stresses are consistent with the surface conditions. The rationale for the shear correction factor used in other first-order theories is obviated. The governing equations including the von Karman nonlinearity are deduced with the required boundary conditions. A wide variety of linear and non-linear results for cross-ply symmetric and antisymmetric laminates are presented. A bending analysis is made to illustrate the influence of the geometric non-linear effect on the transverse deflections and the stresses. Some of the present linear results are compared with their counterparts in the literature. The present results are in good agreement with the results of others. (C) 1999 Elsevier Science Ltd. All rights reserved.