CRACK TIP STRESS SINGULARITIES AND DISLOCATION INTERACTIONS WITH ANISOTROPIC VISCOELASTIC BIMATERIAL INTERFACES

The time evolution of the force on a dislocation and the near tip stress field of a semi-infinite crack, lying at an angle towards the welded interface of a bimaterial and just touching it, is studied. The bimaterial consists of viscoelastic media with the most general anisotropy. Applying the Laplace transform to the field equations gives similar relations to those considered in [3], provided that appropriate elastic coefficients are replaced by their Laplace-transformed viscoelastic counterparts. Numerical methods are then used for the inversion of both the Laplace and Mellin transforms and numerical results for near crack tip stress fields are presented along with asymptotic ones for small and large times. Corresponding results are presented for the force on a dislocation. For simple anisotropies a relation between the force on a dislocation and the time dependence of appropriate crack tip stresses is established.