Computation of dynamic stress intensity factors for three-dimensional cracks in functionally graded materials using interaction integral method.

To investigate understanding and prediction of dynamic fracture behavior of a cracked body, dynamic stress intensity factors (DSIFs) are important parameters. In the present work interaction integral method is presented to compute static and dynamic stress intensity factors for three-dimensional cracks contained in the functionally graded materials (FGMs), and is implemented in conjunction with the finite element method (FEM). By a suitable definition of the auxiliary fields, the interaction integral method, which is not related to derivatives of material properties, can be obtained. For the sake of comparison, center, edge and elliptical cracks in homogeneous and functionally graded materials under static and dynamic loading are considered. Then, material gradation is introduced in an exponential form in the two directions in and normal to the crack plane. Next, the influence of the graded modulus of elasticity on static and dynamic stress intensity factors is investigated. It has been shown that, material gradation has considerable reduction influence on DSIFs of functionally graded material in comparison with homogenous material, while static stress intensity factors can decrease or increase, depending on the direction of gradation material property. [ABSTRACT FROM AUTHOR]