An advanced higher-order theory for laminated composite plates with general lamination angles

This paper proposes a higher-order shear deformation theory to predict the bending response of the laminated composite and sandwich plates with general lamination configurations. The proposed theory a priori satisfies the continuity conditions of transverse shear stresses at interfaces. Moreover, the number of unknown variables is independent of the number of layers. The first derivatives of transverse displacements have been taken out from the inplane displacement fields, so that the C⁰ shape functions are only required during its finite element implementation. Due to C⁰ continuity requirements, the proposed model can be conveniently extended for implementation in commercial finite element codes. To verify the proposed theory, the fournode C⁰ quadrilateral element is employed for the interpolation of all the displacement parameters defined at each nodal point on the composite plate. Numerical results show that following the proposed theory, simple C⁰ finite elements could accurately predict the interlaminar stresses of laminated composite and sandwich plates directly from a constitutive equation, which has caused difficulty for the other global higher order theories.