Abstract: The two-dimensional shell element model and cohesive force model were established by using abqaus finite element simulation software and the brittle constitutive model. Besides, the second nominal stress criterion were also used to simulate the fracture toughness of G_Ⅰ fracture with polyimide as the toughening layer. The influences of the normal phase stiffness, energy release rate and other parameters on the properties of the composites were discussed. The above experimental results, indicate that the simulation results are consistent with the actual situation in the curve trend. With the increase of the energy release rate, the interlaminar toughness increases with the increase of the energy release rate, which is mainly caused by the absorption of energy by plastic buckling such as pumping and breaking of fibers. In addition, the normal phase stiffness has a significant effect on the brittle fracture after interlaminar failure. Larger normal phase stiffness leads to the fluctuation of the load-displacement curve, which shows the interlaminar brittleness.

Key words: composites toughening, G_Ⅰ fracture toughness, finite element analysis