Interlaminar stress analysis of laminated composite beams according to global higher-order deformation theories

Stresses and displacements in laminated composite beams subjected to lateral pressures are analyzed by a global higher-order beam theory which can take into account the effects of both transverse shear and normal stresses. By using the method of power series expansion of displacement components, a set of fundamental equilibrium equations of a one-dimensional higher-order theory for laminated composite beams is derived through the principle of virtual work. Several sets of truncated approximate theories are applied to solve the boundary value problems of a simply supported laminated composite beam. Transverse shear and normal stresses can be calculated by integrating the three-dimensional equations of equilibrium in the depth direction satisfying the continuity conditions at the interface between layers and stress boundary conditions at the top and bottom surfaces. Numerical results are compared with those of the published three-dimensional elasticity solutions.