Abstract
The cohesive zone model (CZM), which is based on the elasto-plastic fracture mechanics, is nowadays widely used in the numerical simulation of the composites ductile crack and progressive delamination. For the sake of tracking the angle-ply composites delamination evolution accurately, the exponential CZM is applied. At first the standard double cantilever beam (DCB) specimen is modeled using the exponential interface damage law to verify the feasibility of it. The simulated results are in good agreement with the analytical results and corrected beam theory. Then in order to investigate how the ply angle influences the mode I fracture, five laminates with different ply orientations, [012/012], [012/3012], [012/4512], [012/6012] and [012/9012], are studied. The main results are obtained as follows. The delamination evolutions corresponding to different ply angles are quite non-uniform. The unidirectional laminate exhibits the stable, continuous crack growth along the specimen, so does the [012/9012] specimen. Whereas the other three specimens show very uneven fracture surfaces. When the plies change from [012/012] to [012/9012], the stiffness along the specimen is gradually reduced correspondingly, so are the distance of the delamination propagation and the peak load, while the corresponding loading displacement increases slowly. The research provides the numerical simulation method to evaluate the multidirectional laminated composites fracture toughness, and then to optimize the composite performance by the design of ply angles.