PSI - Issue 71

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

468

4. Summary This study presents an advanced 3D modeling approach to explore the plastic deformation behavior of polycrystalline materials using a CPFE framework. The framework is enhanced by incorporating a diffused interface model and a biased meshing technique, which together improve the accuracy and efficiency of the simulations. The study successfully captures the grain size effect and reveals significant strain hardening near grain boundaries (GBs), which is driven by large gradients in plastic strain, modeled effectively with the addition of GNDs. The diffused interface model plays a crucial role in ensuring a smooth transition of mechanical properties near GBs, thereby suppressing artificial stress concentrations that could otherwise skew the results. Furthermore, the study introduces a non-local criterion to quantify plastic incompatibility near GB, which enhances the model’s ability to analyze complex microstructural behavior with greater precision. The local stress profiles generated through simulations offer valuable insights into the intricate phenomena occurring within the GB regions, contributing to a better understanding of the material's behavior under deformation. The macroscopic response obtained from simulations performed on a polycrystalline RVE generated from EBSD data, under specified boundary conditions, closely mimics the uniaxial deformation of pure iron. The integration of EBSD data into the CPFE model, coupled with the use of biased meshing and a diffused interface, results in a computationally efficient framework that provides a more realistic and robust platform for analyzing polycrystals. This framework not only advances the understanding of plastic deformation in polycrystalline materials but also holds potential for application in material design and optimization. Acknowledgements This work is sponsored by Hydro-Quebec, Canada. The authors acknowledge the sponsors for funding this effort under the strategic project Modelisation Micromecanique des Aciers (MoMA) J-8587. References Acharya, A., Beaudoin, A., 2000. Grain-size effect in viscoplastic polycrystals at moderate strains. Journal of the Mechanics and Physics of Solids 48(10), 2213 – 2230. Anahid, M., Samal, M. K., Ghosh, S., 2011. Dwell fatigue crack nucleation model based on crystal plasticity finite element simulations of polycrystalline titanium alloys. Journal of the Mechanics and Physics of Solids 59(10), 2157 – 2176. Asaro, R. J., Rice, J., 1977. Strain localization in ductile single crystals. Journal of the Mechanics and Physics of Solids 25(5), 309 – 338. Asaro, R. J., Needleman, A., 1985. Texture development and strain hardening in rate dependent polycrystals. Acta Metallurgica 33, 923 – 953. Cermelli, P., Gurtin, M. E., 2001. On the characterization of geometrically necessary dislocations in finite plasticity. Journal of the Mechanics and Physics of Solids 49(7), 1539 – 1568. Dai, H., Parks, D. M., 1997. Geometrically-necessary dislocation density and scale- dependent crystal plasticity. In: Proceedings of Plasticity ’97, Neat Press, pp. 17 – 18. Kalidindi, S. R., Bronkhorst, C. A., Anand, L., 1992. Crystallographic texture evolution in bulk deformation processing of FCC metals. Journal of the Mechanics and Physics of Solids 40(3), 537 – 569. Kamaya, M., 2004. Influence of grain boundaries on short crack growth behaviour of IGSCC. Fatigue & Fracture of Engineering Materials & Structures 27, 513 – 521. Lee, E., 1969. Elastic-plastic deformation at finite strains. Journal of Applied Mechanics 36, 1 – 6. Ma, A., Roters, F., Raabe, D., 2006. A dislocation density based constitutive model for crystal plasticity FEM including geometrically necessary dislocations. Acta Materialia 54(8), 2169 – 2179. Nye, J. F., 1953. Some geometrical relations in dislocated crystals. Acta Metallurgica 1(2), 153 – 162. Pohl, F., 2019. Pop-in behavior and elastic-to-plastic transition of polycrystalline pure iron during sharp nanoindentation. Scientific Reports 9(1), 15350. Schroeter, B. M., McDowell, D. L., 2003. Measurement of deformation fields in polycrystalline OFHC copper. International Journal of Plasticity 19, 1355 – 1376. Thondiraj, J. M., Paranikumar, A., Tiwari, D., Paquet, D., Chakraborty, P., 2024. Diffused interface crystal plasticity finite element method: biased mesh generation and accuracy. Finite Elements in Analysis and Design 228, 104051.