PSI - Issue 79

Lazar Jeremić et al. / Procedia Structural Integrity 79 (2026) 117 – 123

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were observed in both models, as shown along with total equivalent strain in Figures 7 and 8.

Fig. 5. Mises stress distribution and values for the first BC case model

Fig. 6. Mises stress distribution and values for the second BC case model

Fig. 7. The plastic equivalent strain distribution in the first model

Fig. 8. The plastic equivalent strain distribution in the second model

Based on the presented results, it can be seen that different boundary conditions did not make significant difference in stress/strain values, with the exception of plasticity. Hence, the model with a constrain along the perpendicular axis (X), which would correspond better to the real case was more conservative, and given the level of plastic strain, still represents stable crack growth. Keeping in mind that there was no crack propagation along the depth, the integrity of the pressure vessel was not compromised despite the presence of a crack-like defect in its inner wall. It can also be seen that a certain level of plasticity exists, but its values are low enough to keep the pressure vessel in the safe zone, especially when considering that the approach shown here is overconservative.