PSI - Issue 81

Oleh Yasniy et al. / Procedia Structural Integrity 81 (2026) 244–250

249

response under thermal fatigue is governed not only by individual crack growth but also by the evolving geometry of the entire crack network.

Fig. 3. Overall (mean) SIF under different equivalent thermal stress.

Fig. 4. Overall mean crack length (a) and distance between cracks (d) under thermal fatigue.

Overall, the obtained results confirm that thermal fatigue leads to progressive crack initiation, growth, and densification of the crack system. The increase in mean SIF and crack length, accompanied by the reduction in mean crack spacing, provides a quantitative measure of damage accumulation. The visualizations of cracks overlaid on the von Mises stress background illustrate the strong coupling between stress redistribution and crack evolution. These findings underline the importance of accounting for crack interaction and stress field heterogeneity in the analysis of thermally loaded structures. The numerical approach successfully captures the key features of thermally induced fracture processes and provides a consistent framework for assessing the degradation of material integrity under cyclic thermal loading. 4. Conclusions The developed numerical approach combines Monte Carlo simulation of crack initiation with a dual boundary element method to accurately evaluate stress fields and stress intensity factors. This integration enables consistent modeling of both stochastic crack nucleation and deterministic crack growth under thermal fatigue. The approach effectively captures the evolution from isolated microcracks to a network of interacting cracks. Mutual crack interaction and its influence on stress redistribution are explicitly taken into account. The use of experimentally calibrated damage laws ensures physical realism of the simulations. The results show a clear increase in the overall mean stress intensity factor with rising equivalent thermal stress. At the same time, the mean crack