An improved simple third-order shear deformation theory for laminated composite plates

Transverse shear effects are very important for the bending behavior of laminated plates. Based on the refined simple third-order shear deformation theory for the analysis of orthotropic plates proposed by Shi (2007), an improved higher-order theory for laminated plate analysis is presented in this paper. This new laminated plate theory consists of (1) the simple third-order kinematics of displacements reduced from the higher-order displacement field, and (2) a system of differential equilibrium equations with the total differential order of ten. The exact solutions of the equilibrium equations for simply supported, symmetric cross-ply rectangular or square plates are taken into consideration in the numerical simulation. The calculated results are compared with those obtained by three-dimensional elasticity solutions and other higher-order shear deformation theory solutions. These analytical results indicate that the presented refined simple third-order shear deformation theory of laminated plates is more reliable and accurate than the first-order shear deformation theories and other simple higher-order shear deformation theories.