A Computation Model And Application Of Fracture Analysis Of Functionally Graded Materials

Functionally graded materials(FGMs) are a new type of composites. Fracture mechanics analysis of such materials is essential to their optimum design. However, the properties of FGM may vary arbitrarily along a certain spatial direction, Which makes the direct analysis very difficult in mathematics. Based on the fact, A predecessors model is applied in this article: the functionally graded materials are divided into several sub-layers, and we postulate the material parameters change along to linear functions in each sub-layers. Material parameters are continuous on the sub-interfaces and equal to their real values. And the test shows that this model is very effective.Meanwhile the J~* integral of functionally graded materials that represent the parameter of crack-tip field have been studied in this paper. It has shown that for FGMs crack problems the path independent J~* integral has the physics meaning of energy release rate of crack-tip and has relationship with the stress intensity factors.Then the stress intensity factors of crack-tip under given angles are concerned and studied, which is based on the present model and finite element method.So the model and J~* integral may be very effective in fracture mechanics analysis. All these works can provide theoretical base and gist for the future research of FGMs.