Phase-field modelling of fatigue crack propagation

Abstract

Fracture prediction and modeling are crucial in studying the behavior of materials under stress. This research focuses on utilizing the phase field method for accurate fracture prediction, which offers distinct advantages over traditional methods by representing fractures implicitly as smooth fields. The phase field method was implemented and analyzed using Matlab and COMSOL as tools, aiming to investigate and gain insights into the ease and feasibility of phase-field modelling for fatigue fracture problems. This was conducted mainly by introducing a fatigue degradation function, with the purpose of simulating the degrading process of the material after repeated cyclic loading. Through comprehensive analysis, quantities of interest such as the history variable, accumulated strain energy, and damage variable were examined. The obtained trends and results were found to align with existing literature, although neither calibration nor validation was conducted due to time limitations. Suggestions for future work include implementing a force-controlled load, calibration of the fatigue degradation function for a larger amount of load cycles, and validation with experimental data. Nevertheless, the results obtained from the fatigue implementation can provide a solid foundation for continued research. In conclusion, the progress during the project highlighted the potential of the phase-field model to predict fatigue fracture by modelling the crack through a damage field. Hence, fatigue prediction using phase-field modelling has the potential to make significant progress and thus contribute to less computationally expensive simulations for more complex fatigue fracture problems.