Issue 51

A. A. Lakhdari et alii, Frattura ed Integrità Strutturale, 51 (2020) 236-253; DOI: 10.3221/IGF-ESIS.51.19 245 Calculations show that there is no redistribution of stresses because the hydrogen concentration does not change in both time and volume of the structural element. As a result, hydrogen has virtually no effect on the stress state of the structural element. Loading №2. The hollow cylinder is under external pressure out P 20 МPа  , the internal pressure is equal to 0. The hydrogen concentration on the inner and outer surfaces is kept constant, but with different values. The concentration field of hydrogen is shown in Fig. 9. The intensity of the stresses is shown in Fig. 10. The radial, tangential and axial stresses at time t = 10 are shown in Figs 11, 12.13. Figure 9 : Concentration field of hydrogen. Figure 10 : Intensity of constraints at the moment 10. t  In Fig. 14, the stress intensity curves S INT , the axial stresses S Z , radial and tangential stresses S X and S Y are presented according to the thickness of the wall of the cylinder at time t =10. Note that the deformation pattern does not change over time; however, it is individual for each finite element due to the fact that the concentration field is not uniformly distributed in the volume of the structural element. The graphs show a change in the character of the stress curves. The redistribution of the tangential stresses and, consequently, of the stress intensities is particularly remarkable. Loading №3. The loading is similar to the load №2, only the external pressure is out P 30   MPa. The concentration field is stationary and is shown in Fig. 15. The intensity of the stresses is shown in Fig. 16. The radial, tangential and axial stresses at time t =18 are presented in Figs. 17, 18, 19. In Fig. 20, the stress intensity curves S INT , the axial stresses S Z , radial and tangential stresses S X and S Y are presented according to the thickness of the wall of the cylinder at time t =18.