Predicting the debonding formation and induced matrix cracking evolution in open-hole composite laminates using a semi-consequence micro-macro model

Here, a new Integrated Micro/Macro (IMM) approach is proposed to consider the impact of debonding and its induced matrix cracking on the macro response of composite laminates. To this purpose, a new micromechanics formulation based on complex variable elasticity is developed to calculate the stress and displacement fields along the perfect/imperfect bonded interface between rigid inclusion (fiber) and matrix under general remote stresses. Then, by employing strength based and Griffith failure energy criteria, the initiation and growth of debonding angle will be examined respectively. To obtain the stiffness degradation due to debonding formation, the shadow of the interfacial cracks in different directions is employed. The obtained stiffness reductions are employed to develop new relations for the calculation of damage parameters. The damage parameters are dependent on the terms of the debonding angle, radius and volume fraction of inclusion. Then, by the implementation of the impact of the diffusion debonding using the proposed damage parameters into ANSYS commercial software via a developed IMM code, the precision of the methodology on the modeling of the mentioned damage mechanisms is assessed by comparison with the available experimental results. The matching between the proposed method and experiments implies that IMM approach provides a reliable tool to the precise prediction of the nonlinear response of composite laminates containing an open hole due to the debonding initiation and propagation.