Torsion crack in a piecewise homogeneous body with a thin layer at the interface

The influence of a thin layer in a piecewise homogeneous body consisting of half-spaces on the stress intensity in the vicinity of a circular torsion crack is studied by the method of the boundary-integral equations. Two approaches to modeling a thin layer are considered – accurate considering its geometric dimensions and approximate using effective boundary conditions in the form of a spring contact at the interface. The limits of applicability of spring contact conditions for modeling the interlayer have been established.