Decohesive carrying capacity of a disk under tension and in-plane torsion

An elastic±perfectly plastic circular disk, with rigid circular inclusion of the radius a, subjected to simultaneous uniform radial tension and in-plane torsion is considered. External radius of the disk is assumed to be in®nitely large, just to simplify the boundary conditions. Limit load-carrying capacity of such a disk cannot be reached, it is preceded by decohesive carrying capacity (DCC), de®ned by in®nitely large radial strains er. They attain their upper bound for r ˆ a; then the shearing strains gry at r ˆ a increase in®nitely as well. In contradistinction to the limit carrying capacity, the decohesive carrying capacity depends essentially on Poissonʹs ratio v. Interaction curves corresponding to DCC are shown in the plane of external loadings. A comparison with the condition of discontinuous bifurcation under uniform stresses and strains is given, and full agreement is found, though in the case under consideration the state of stress is evidently non-uniform. Diagrams of stress and strain distribution at the moment of decohesion are also presente