PSI - Issue 17

J.P. Pascon et al. / Procedia Structural Integrity 17 (2019) 411–418 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 4. Fatigue crack growth data for peak load 20.5 kN from Torres et al. (2017).

The size of the plastic zone was obtained by measuring the horizontal distance from the crack tip to the point with the smallest value of non-zero equivalent plastic strain, i.e., the point with the smallest level of plastification. It has been observed that the monotonic plastic zone size varies from 0.12 to 0.13 mm for all the analyses. This can be explained by the fact that, although the plastic zone size remains practically the same, the level of hardening around the crack tip increases along the cycles applied. The comparison of the final values of the equivalent plastic strain ( κ ) around the crack region is depicted in Figure 5. One can note that, although the values are higher for the load ratio R = -1, the shape of the region that has achieved the plastic regime is almost the same for both load ratios. The values of the equivalent plastic strain are higher for the left part of the crack region because, as the crack length increases, the remaining cross-sectional area decreases and, thus, the stress becomes higher.

Fig. 5. Final equivalent plastic strain ( κ ) around the crack line.