The interface crack in anisotropic bodies. stress singularities and invariant integrals

For the problem of the deformation of a composite anisotropic plate with a crack (in a linear formulation, with no assumption of symmetry), all possible power solutions are listed and general relations between the ordinary and singular solutions are revealed. The asymptotic form of the increment of the potential energy of deformation is computed for the cases of the rectilinear propagation of the crack, deviation of a shoot or branching. The form obtained for the final formula is the same as the classical version of the Griffiths formula and involves two invariant integrals. Two methods of determining the modes of radical singularities of the stress-strain state near the crack tip, associated with the use of force and energy criteria, are proposed.