PSI - Issue 71

Ayub Khan et al. / Procedia Structural Integrity 71 (2025) 461–468

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comparison was confined to the elasto-plastic regime, encompassing both yielding and strain hardening, but excluding damage accumulation. The calibrated simulation input parameters are given in Table 2.

Fig. 5. Macroscopic response of Polycrystalline RVE compared with stress-strain curve of Pure Iron. Table 2. Simulation input properties calibrated from pure iron. 1 327.6 GPa 2 133.83 GPa 3 48.45 GPa Reference slip rate, 0 ̇ 0.008 −1 Strain rate sensitivity, 0.058 Initial hardening rate, ℎ 0 150 MPa Ratio self/latent hardening, 1.4 Initial slip resistance, 0 80 MPa Dimensionless constants (GND), 0 & ̂ 3 & 5

1.8. Case IV :Polycrystal (EBSD data) mesh, Effect of GNDs In this case, simulations are performed on the polycrystalline RVE shown in Fig. 2(b), with the simulation input parameters generated from Case III. As the material accumulates more plastic strain, the hardening near the GB is observed to be relatively hig her in the ‘SSD and GND’ model. This is clear in the local stress profile (Fig. 6(a)), which clearly shows more hardening due to the addition of GNDs. The difference in magnitudes of the stresses obtained from both the models (with and without GND) is observed to be more near the GB, which means that hardening near the GB, which is the region of higher strain gradients, is accurately captured.

Fig. 6. Effect of GNDs on polycrystal RVE. (a) Line plot on section z=0.5, and (b) Macroscopic response.