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 penny-shaped torsion crack is studied by the boundary integral equations method. Two approaches to modeling a thin layer are considered: an accurate, considering its geometric dimensions, and approximate, using effective boundary conditions in the form of a spring contact at the interface. The applicability limits of spring contact conditions applicability for modeling the interlayer are established.