PSI - Issue 61

Orhun Bulut et al. / Procedia Structural Integrity 61 (2024) 3–11 O. Bulut et al. / Structural Integrity Procedia 00 (2024) 000–000

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Fig. 5. Damage evolution represented by the phase field parameter on the path

representations of both elastic and plastic deformation and directly a ff ects the stress carrying capacity of the material through a degradation function. A higher order degradation function is utilized in this work to delay the premature degradation in the early stages of deformation. The model’s performance is assessed in bi-crystal and polycrystal numerical examples. In a hard-soft grain pair, the e ff ect of misorientation on the crack nucleation is examined. With higher misorientation angles, the failure occurred earlier in the loading history demonstrating a higher a ffi nity for crack nucleation at the hard-soft grain interfaces with this e ff ect eventually saturating at about 65°. The crack then propagated into the soft and hard grain simultaneously, resulting in a slanted crack. The model’s capabilities are demonstrated in a randomized polycrystalline structure under a uniaxial constant strain rate where it is able to capture intra and inter-granular crack initiation and propagation. Finally, a polycrystal example with a soft-hard-soft grain structure is simulated under cyclic loads with and without dwell period. The model is able to capture the load shedding phenomenon after cyclic dwell loading. The main contributor to the growth in the phase field is found to be the dwell periods, as no significant increase is observed under cyclic loading without a dwell hold. Acar, S.S., Bulut, O., Yalc¸inkaya, T., 2022. Crystal plasticity modeling of additively manufactured metallic microstructures. Procedia Structural Integrity 35, 219–227. Ambati, M., Gerasimov, T., De Lorenzis, L., 2015. Phase-field modeling of ductile fracture. Computational Mechanics 55, 1017–1040. Anahid, M., Samal, M., Ghosh, S., 2011. Dwell fatigue crack nucleation model based on crystal plasticity finite element simulations of polycrys talline titanium alloys. Journal of The Mechanics and Physics of Solids 59, 2157–2176. Aydiner, I.U., Tatli, B., Yalc¸inkaya, T., 2024. Investigation of failure mechanisms in dual-phase steels through cohesive zone modeling and crystal plasticity frameworks. International Journal of Plasticity 174, 103898. Bache, M.R., 2003. A review of dwell sensitive fatigue in titanium alloys: the role of microstructure, texture and operating conditions. International journal of fatigue 25, 1079–1087. Borden, M.J., Hughes, T.J., Landis, C.M., Anvari, A., Lee, I.J., 2016. A phase-field formulation for fracture in ductile materials: Finite deformation balance law derivation, plastic degradation, and stress triaxiality e ff ects. Computer Methods in Applied Mechanics and Engineering 312, 130–166. Borden, M.J., Verhoosel, C.V., Scott, M.A., Hughes, T.J., Landis, C.M., 2012. A phase-field description of dynamic brittle fracture. Computer Methods in Applied Mechanics and Engineering 217-220, 77–95. Bourdin, B., Francfort, G.A., Marigo, J.J., 2000. Numerical experiments in revisited brittle fracture. Journal of the Mechanics and Physics of Solids 48, 797–826. Bulut, O., Acar, S.S., Yalc¸inkaya, T., 2022. The influence of thickness / grain size ratio in microforming through crystal plasticity. Procedia Structural Integrity 35, 228–236. Bulut, O., Gu¨nay, E., Fenerciog˘lu, T.O., Yalc¸inkaya, T., 2023. Analysis of additively manufactured anisotropic microstructures through crystal plasticity frameworks. Materials Research Proceedings 28, 179–188. Carrara, P., Ambati, M., Alessi, R., De Lorenzis, L., 2020. A framework to model the fatigue behavior of brittle materials based on a variational phase-field approach. Computer Methods in Applied Mechanics and Engineering 361, 112731. References