Critical states of thin-walled cylindrical shells with annular seams under axial compression and internal pressure

We consider the loading conditions of a thin-walled cylindrical shell containing an annular layer of less durable material under its axial compression and internal pressure. The main pipeline of seamless pipes of large diameter containing annular mounting seams is considered as an application. The main material of the shell and the material of the layer are elastoplastic hardenable. The limits of strength and yield strength of the layer are lower than these values of the base material. The purpose of the article is to establish the dependences of critical deformations, stresses and pressures on the shell on its mechanical and geometric parameters and loading conditions. The research method is based on the application of the Swift — Marciniak criterion for the loss of stability of the process of plastic deformation of the material using new approximations of deformation diagrams. Explicit analytical expressions for the required quantities are obtained. The results make it possible to determine the critical pressures under given loading conditions and the pipeline wall thicknesses at a given operating pressure.