Development of a layer-wise model together with J-integral method for prediction of interlaminar crack growth in laminated composites plates

In this paper, a numerical method is developed in order to predict the crack growth in multi-layerd composites. Reddy's layerwise theory is em employed to truly calculate the the interlaminar stresses and afterward the accuracy of results are satisfied by Abaqus finite element software. Then the capability of solving problems in the presence of delamination, as the most important cause of composites failure, is added to the elaborated model. In fallows, the J-integral method, which the integral is independent of the path around a crack, is introduced and by using the this method, the initially layerwised model is improved. Also, failure in structure is controlled by strain energy release rate; This means that firstly the process of computing total stiffness matrix of structure using layerwise element is described and nodal displacements and stress-strain fields in elements are extracted. Subsequently the possibility of predicting the crack growth is achieved by calculating the 3D J-integral using the criterion of strain energy release rate at crack front. Finally, the developed numerical model is validated by comparing the its results with the results of available analytical models and it is perceived that the model, despite being unique, is more similar to some of the analytical solutions