CREEP AND LONG-TERM DESTRUCTION OF A CYLINDRICAL SHELL IN A NON-STATIONARY COMPLEX STRESS STATE IN THE PRESENCE OF AN AGGRESSIVE ENVIRONMENT

Abstract—

The study is based on the results of creep up to destruction tests of tensile specimens of titanium alloy VT6 at 600°C, into which hydrogen of various concentrations was previously introduced. In this work, a theoretical generalization of the data obtained for a non-stationary complex stress state is carried out. The modeling of the creep of a cylindrical shell up to destruction with two programs for the dependence of axial and transverse stresses on time is considered. It is assumed that the shell material was pre-saturated with embedded hydrogen of various concentrations. The description of creep is carried out taking into account physical and geometric nonlinearity. To describe long-term fracture, the kinetic theory of Yu.N. Rabotnov with a vector parameter of damage is used. In the first part, the piecewise constant dependence of axial and transverse tensile stresses on time is considered. It is shown that the times until the destruction of the shell coincide with a stepwise increase and decrease in the same stress values. In the second part, the loading of the shell is considered, in which the axial and transverse stresses increase in proportion to time. The curves of the axial creep of the shell up to fracture were obtained at various rates of stress increase.