Investigation of nonlinear deformation and stability of a composite cylindrical shell under combined torque load, bending moments, and internal pressure

The problem of stability of cylindrical shells made of composite material, taking into account momentum and nonlinearity of their subcritical stress-strain state. Geometrically non-linear the stability problem is solved by finite element methods and linearization of Newton–Kantorovich. Critical loads are determined in the process of solving a nonlinear problem using Sylvester's criterion. Hypothesized Timoshenko finite elements of composite cylindrical shells natural curvature, in the approximation of displacements of which in explicit form, rigid displacements are highlighted, which significantly affects solution convergence. The stability of the circular cylindrical shell made of polymer composite material, under combined loading by torsional and bending moments and internal pressure. Studied the influence of the laying method monolayers, non-linearity of deformation, internal pressure on critical loads at which buckling occurs shells.