PSI - Issue 75

8

Author name / Structural Integrity Procedia (2025)

S.S. Penkulinti et al. / Procedia Structural Integrity 75 (2025) 1–9

8

3.2. Impact of loading type on fatigue strength anisotropy The previous analysis has been extended to other loading types, considering pure shear loading and in-phase combined tension-shear loading with a biaxial stress ratio of 1. Fig. 5 provides the anisotropic factor obtained for the different defect populations using local and non-local analyses. As opposed to the uniaxial loading, the presence of LoF defects results in limited anisotropy of the fatigue strength when a pure shear loading is applied, the anisotropic factor obtained for LoF defects being similar to the one obtained for gas pores ( ~ 1.2 for local analyses, ~ 1.1 for non-local analyses). For the combined tension-shear loading case, slight anisotropy is observed for the LoF population for the non-local analysis ( = 1.45 ), while when non-local analysis is considered the LoF anisotropic factor is reduced and similar to the one obtained for gas pores ( ~ 1.1 ).

Fig. 5: Comparison of the anisotropic factors obtained for the different loading types (from Penkulinti et al. (2025)).

4. Conclusions This work has proposed a numerical methodology to assess the impact of L-PBF defects on the anisotropy of the fatigue resistance. The proposed approach allows to determine numerically the fatigue resistance for multiple loading directions by using a limited set of FE computations. The main conclusions can be summarized as follows: • LoF defects are highly sensitive to loading direction, unlike gas pores. • The anisotropy of the fatigue behavior due to the defect is much more pronounced for the uniaxial loading case compared to the other multiaxial loading cases. • Considering stress gradients in the fatigue criterion through non-local analyses reduces the anisotropy. References Bonneric M., Saintier N., El-Khoukhi D., Bega J., 2025. Influence of the defect size, type, and position on the High Cycle Fatigue behavior of Ti 6Al-4V processed by laser powder bed fusion. International Journal of Fatigue 193. Bunge, H.J., 1982. Texture analysis in materials science: mathematical methods. Butterwoth & Co.