Geometric non-linear analysis of imperfect composite laminated plates, under end shortening and pressure loading, using finite strip method

Description is given of semi-analytical finite strip method for predicting the geometrically non-linear response of rectangular composite laminated plates with initial imperfections, when subjected to progressive end shortening and pressure loading. In the finite strip formulations, the initial imperfections are all assumed to be of the sinusoidal shape in both of the longitudinal and transverse direction. The laminates are simply supported out of their plane at the loaded ends as well as unloaded edges. The plates are assumed to be thin so that the analysis can be carried out based on the classical plate theory. Geometric non-linearity is introduced in the strain–displacement equations in the manner of the von Karman assumptions. The formulations of the finite strip methods are based on the concept of the principle of the minimum potential energy. The Newton–Raphson method is used to solve the non-linear equilibrium equations. A number of applications involving plates with both initial imperfection and pressure load are described and discussed.