UBC Theses and Dissertations
Phase-field modelling of crack propagation Li, Zhuo
Brittle fracture has been investigated for more than a century. Various models managed to capture the fracture phenomena, among which the phase-field models gained popularity in the mechanics and the physics community in the past two decades. However, due to distinct backgrounds, detailed comparisons between the phase-field models in the two communities are missing. Therefore, to understand the strengths and limitations of these models, this study aims to compare them in the same settings. Quasi-static and dynamic brittle fractures are investigated in the current work, of which the main difference is the loading speed. Since numerous phase-field models have been developed in both communities, in the present work, only the most representative models are selected, i.e., Miehe et al.'s model and the Karma-Kessler-Levine (KKL) model. Through comparisons with the Griffith theory, in quasi-static simulations, the unphysical dependence of the energy release rate on the load in the KKL model was observed. Meanwhile, in dynamic fracture, both models showed good agreement with the theories by Eshelby and Adda-Bedia in some aspects while deviations in others. The results suggest that for quasi-static fracture, Miehe et al.’s model is a reasonable option. While for dynamic fracture, comparisons with experiments are necessary to evaluate the accuracy of the models.
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