PSI - Issue 71

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

466

Fig. 3. Comparison of results obtained for sharp and diffused interface. (a) & (b) are Line Plots on section z=0.5, and (c) macroscopic response.

Table 1. Properties used in the CP model.

1 2 3

100.17 GPa 47.14 GPa 26.515 GPa 0.001 −1 0.02 180 MPa

Reference slip rate, ̇ 0 Strain rate sensitivity, Initial hardening rate, ℎ 0 Ratio self/latent hardening, Initial slip resistance, 0

1.4

16 MPa

1.6. Case II : Bicrystal with Diffused Interface In this case, simulations are performed using the diffused interface model on a bicrystal RVE, and the additional hardening effect because of GNDs is studied. The results from the ‘SSD only’ model are compared with the ‘SSD and GND model’. The line plot (Fig. 4(b)) and the macroscopic response (Fig. 4(c)) show the hardening with the addition of GNDs in the model. The hardening effect is observed to be stronger in the GB region, where the strain gradients are higher.

Fig. 4. Diffused interface with and without GNDs. (a) & (b) are Line Plots on section z=0.5, and (c) macroscopic response.

1.7. Case III: Polycrystal (EBSD data) mesh (Without GND) In this case, a subdomain is taken for analysis from the EBSD data obtained for polycrystalline pure iron (Fig. 2(b)). A 22226 elements biased mesh is then generated for the subdomain by a 2 step coarsening procedure, and simulations are performed on the RVE with the ‘SSD only’ model. The stress-strain data obtained from uniaxial tensile tests of pure iron (Pohl (2019)) were employed to calibrate the parameters of the CPFE model. This calibration involved matching the macroscopic response of the simulated RVE to the experimental stress-strain data (Fig. 5). The