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To obtain the flexural response and the load-carrying capacity of composite plates with delamination, an efficient closed-form analytical solution is presented. Layerwise Higher-order Shear Deformation Theory and Rayleigh-Ritz approximation technique are applied. Fracture analysis is used to obtain the load-carrying capacity and primary steps of delamination propagation. The results include continuous functions. Furthermore, a considerable experimental study has been performed with specimens of various geometries and delamination types. The experimental investigation includes the fabrication procedure, tension experiments to obtain material properties and three-point bending tests of the delaminated plates.

A Layerwise Higher Order Shear Deformation Theory is developed for plates containing rectangular embedded delaminations undergoing non negligible lateral deflections. The effects of different parameters of the composite laminate and delaminated area are investigated analytically under buckling load and the results are compared with the three dimensional finite element analysis. The results demonstrate the effects of different geometrical parameters of the delaminated area and thickness on the deflection of a composite laminate. Also the initiation of debonding in opening and sliding fracture modes is predicted using the developed formulation.

The effects of different parameters of the composite laminate and delaminated area are investigated analytically under buckling load based on a developed Layerwise Higher Order Shear Deformation Theory and the results are compared with the three dimensional Finite Element Analysis. The results demonstrate the consequences of different geometrical parameters of the delaminated area, lay-up sequences and thickness of the laminate on the deflection of a composite plate containing through-the-width delamination.

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.