A semi-analytical study on effects of geometric imperfection and curved fiber paths on nonlinear response of compression-loaded laminates

Variable stiffness composite plate can adjust the stiffness properties of the plate in order to satisfy the design requirements of studied problem. In this paper, the effects of different types of boundary conditions, lay-ups, sizes and shapes of geometric initial imperfection on the nonlinear behavior of VAT plates are investigated; these conditions influence the behavior of the plate completely. Moreover, the first-order shear deformation plate theory and Von-Karman assumptions are applied to analyze the effects of fiber lay-up sequences of VAT-laminate under different boundary conditions. Ritz method is also exploited by using Legendre polynomials to approximate the unknown displacement fields of the problem. To yield more accurate results, potential energy integrals are numerically calculated by employing Gauss-Lobatto formulas. Lastly, the system of nonlinear equations is solved by the well-known Newton-Raphson technique. In order to validate the results, finite element analysis is also implemented by the commercial finite element package ABAQUS.