Modeling crack propagation in variable stiffness composite laminates using the phase field method

The fracture processes of the constant/variable stiffness composite laminate (CSCL/VSCL) subjected to uni-axial tension is investigated using the phase-field method. The main objectives of this work are: (a) to study the crack propagation path and (b) to investigate the influence of the fiber-matrix interface on the crack path. In particular, the emphasis is to explore the role played by the orientation of the fiber and the inter-fiber spacing on the fracture pattern in the composite. From the numerical study, it is inferred that (a) the cracking pattern of the composite is significantly influenced by the orientation of the fiber and (b) the load carrying capacity of the composite enhances with the increase in the orientation of the fiber. For a larger inter-fiber spacing, the load-displacement curve does not alter significantly for different orientations of the fiber. Furthermore, a novel approach to predict the load-displacement curve of the composite using an equivalent homogenized orthotropic material is presented, showing a very good agreement between them. It is seen that the location of the crack in the VSCL influences the failure load.