Three-dimensional state space spline finite strip analysis of angle-plied laminates

In this paper, a combined spline finite strip and state space approach is introduced to obtain three- dimensional solutions of laminated composite plates with general boundary conditions. Spline and linear polynomial functions are used, respectively, as the shape functions in the longitudinal and transverse directions of the strips. The variations of the displacements and stresses through the thickness of a strip are calculated through solving differential equations in the form of the state space equations. This method allows the displacements and stresses to be computed simultaneously at all nodes along the nodal lines. In comparison with three dimensional finite element solutions, the current method guarantees the continuity of all the displacements and through-thickness stresses across all interfaces of material layer and, therefore, provides more reliable and accurate results. It can also reduce the computational effort when compared with the traditional three-dimensional finite element and finite strip methods