A crack at the interface of anisotropic bodies. Singularities of the elastic fields and a criterion for fracture when the crack surfaces are in contact

Novozhilov's quasistatic brittle fracture criterion is used to determine the direction angle of the branch of a crack with closed surfaces at the interface of two anisotropic bodies. The asymptotic form of the elastic fields near the crack tip is investigated and corollaries of Novozhilov's criterion are derived in an asymptotic formulation. Normalizations of the singular solutions, which have been adapted to the force and deformation fracture criteria, are discussed. In particular, it is established that, in the case of general anisotropy, there is no oscillation of the crack surfaces which can appear in the solution of the linear problem for an open crack.