Direct adjustment procedure for weight functions of graded materials

The weight function procedure simplifies the determination of stress intensity factors. If the weight function is known for a crack in a component of homogeneous material, the stress intensity factor can be obtained by multiplying this function by the stress distribution and integrating it over the crack length. In the case of graded materials, weight functions are seldom available in the literature. The main point of this paper is to demonstrate whether or not the approximate direct adjustment procedure for the derivation of weight functions is also valid in the case of graded materials. In this study it has been found that the procedure is applicable and no changes are necessary compared with the procedure for homogeneous materials.