Abstract: The strain energy release rates of cracks with different directions in short-fiber reinforced composites were calculated using vitual crack propogation method combined with finite element method. The influence of mesh size as well as the crack length, fiber length, fiber radius and fiber content on the calculation results were studied. It is shown that, the mesh size has little effect on the calculation results; the strain energy release rates of cracks in different regions of composites vary differently with the crack length; it presents a regular change pattern with the variation of crack direction and the minimum of propagation resistance happens in the sliding crack; and the strain energy release rates increases as the increasing of fiber length, fiber radius and fiber content.

Key words: composites, short fiber, fracture, numerical simulation