Analytical and experimental study of the ultimate strength of delaminated composite laminates under compressive loading

An improved and efficient analytical solution is proposed to predict the behaviour and the ultimate strength of composite laminates containing delamination. For this purpose, a Layerwise Higher order Shear Deformation Theory based on polynomial shape functions using Rayleigh–Ritz approximation technique are utilized. The ultimate strength and initial stages of propagation of the delaminated zone are determined using fracture analysis. The results demonstrate continuous functions to calculate in-plane and out-of-plane displacements, rotations, strains, stresses, energy and load carrying capacity under in-plane compressive loading. Moreover, a significant experimental investigation has been carried out for specimens with cross-ply stacking sequence and various material properties, geometries, delamination type and boundary conditions. The experimental study includes fabrication process, tensile tests to determine material properties and buckling test of the defected specimens.