MIXED-MODE J-INTEGRAL METHOD FOR ANALYSIS OF 3D FRACTURE PROBLEMS USING BEM

In this paper three-dimensional, mixed-mode stress intensity factors a re obtained by the application of the J-integral technique to the boun dary element method. The J-integral is split into the three modes of c racking by two different methods. The decomposition method uses the mo de I, II, III stress, strains and derivatives of strain to obtain the mode I, II and III J-integrals. The displacement ratio method decouple s the J-integral, comprised of anti-symmetric elastic fields, into mod e II, III components via the crack face displacements. Stress intensit y factors are calculated directly from the mode I, II and III J-integr als. The implementation of the J-integral is validated against a known theoretical solution - namely, an inclined penny-shaped crack in an i nfinite domain. Finally, the method is used to calculate stress intens ity factors for complex components typically encountered in the aircra ft industry.