Creep and long-term strength modeling for thick-walled tubes under combined loading with axial force, torsional moment and internal pressure

We have developed a method for solving the boundary-value problem of rheological deformation and creep rupture of thick-walled tube under combined loading with axial force, torsional moment and internal pressure. Energetic variant of the theory of creep and long-term strength is used to describe creep process. Experimental verification of proposed method has been performed using known test data for creep and long-term strength of thick-walled tubes made of D16T alloy and Steel 20. Calculated dependencies for total axial strain and torsion angle on time are obtained. The results of calculation and estimated deviations for long-term strength are given. It is shown that the calculation data fit to experimental values as well as calculation data obtained by other scientists in third-party sources.