Stability of elastic cylindrical micropolar shells subject to combined loads

The present paper is devoted to the stability analysis of a compressed cylindrical shell (tube) under internal and external pressure. The problem is investigated within the framework of nonlinear Cosserat theory of elasticity. By solving the three-dimensional linearized equilibrium equations numerically, spectra of critical values for deformation parameters and corresponding instability modes are found, and also the stability regions in space of these parameters are constructed. On the basis of obtained results the influence of shell geometry on its stability is analyzed. Some general conclusions on the effect of couple stresses on an equilibrium bifurcation of a cylindrical shell made of micropolar medium are formulated.