PSI - Issue 57

Sanjay Gothivarekar et al. / Procedia Structural Integrity 57 (2024) 487–493 S. Gothivarekar et al./ Structural Integrity Procedia 00 (2023) 000 – 000

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3. Results 3.1. Stress-output

Fig. 5. (a) Stress-output for entire specimen (b) Stress-output for Voronoi part for a nominal stress level of 440 MPa.

When examining the von Mises stress-output in Figure 5 (a), a smooth distribution can be noticed and the maximum stress is located near the center towards the edge of the specimen. However, a closer look at the central region reveals more variation and irregularity in the stress caused by the elastic heterogeneity in the Voronoi part. From Figure 5 (b) it is clear that the variation in stiffness causes an uneven stress distribution with stress peaks near to the crystal boundaries. In general, the assumption of a linear elastic material model is valid as the stress is limited to 440,7 MPa. 3.2. Fatigue life estimation Considering that the experimental location of crack imitation is consistently located at the edge of the specimen [2], the SWT calculation was performed for a set of several grains close to the edge. The minimum and maximum stress- and strain-outputs for every element in this set are used to compute the SWT damage parameter according to the left-hand side of equation (1). The result can then be exported as a new field-output, as shown in Figure 6 (a).

Fig. 6. (a) SWT-output of Voronoi part (b) Overlay plot of fatigue life estimation and material sections for a stress level of 420 MPa.