Deformation of a thin film after contact loss with a cylindrical base, with accounting for the influence of its curvature, compliance, and action of transverse forces; delamination located in the circumferential direction

The process of delamination of a coating from a cylindrical substrate under the action of compressive stresses is considered. The solution of the problem was obtained within the theory of cylindrical shells. The Mushtari-Donnell-Vlasov equations were used as the equilibrium equations, and the conditions of the generalized elastic clamped type were used as the boundary conditions. Expressions are obtained for the coating displacement components and the energy release rate during delamination along the rectilinear and curvilinear delamination boundaries. The profiles of the exfoliated section of the coating were obtained. The role of the substrate compliance and its curvature on the values of the energy release rate and the angle of rotation at the clamping point, as well as in the change in the shape of the coating profile, is revealed. It is shown that with an increase in the compliance of the substrate, as well as the value of (positive) curvature, the value of the energy release rate and the value of the normal component of the displacement of the coating increase significantly. It has been found that at sufficiently large values of the substrate curvature, a corrugation effect occurs in the profile of the delaminated section of the coating, which leads to the appearance of local extrema in the graph of the dependence of the energy release rate on the delamination length. This effect was not observed in the delamination located in the longitudinal direction [1]. It is also shown that for sufficiently compliant substrates there is a certain critical delamination width, for which it becomes energetically more favorable for delamination to develop in the circumferential direction than in the axial one. As the positive curvature and compliance of the substrate increase, the value of the critical width decreases. An alternative criterion for the critical delamination width is also considered, which consists in studying the value of the angle of rotation at the embedding point, which corresponds to the overlap of the coating and substrate surfaces at an angle value of zero.