An FFT-based crystal plasticity phase-field model for micromechanical fatigue cracking based on the stored energy density S. Lucarini a,* , F.P.E. Dunne b , E. Mart´ ınez-Pa˜ neda a,* a Department of Civil and Environmental Engineering, Imperial College London, London SW7 2AZ, UK b Department of Materials, Imperial College London, London SW7 2AZ, UK Abstract A novel FFT-based phase-field fracture framework for modelling fatigue crack initiation and prop- agation at the microscale is presented. A damage driving force is defined based on the stored energy and dislocation density, relating phase-field fracture with microstructural fatigue damage. The formulation is numerically implemented using FFT methods to enable modelling of sufficiently large, representative 3D microstructural regions. The early stages of fatigue cracking are simu- lated, predicting crack paths, growth rates and sensitivity to relevant microstructural features. Crack propagation through crystallographic planes is shown in single crystals, while the analysis of polycrystalline solids reveals transgranular crack initiation and crystallographic crack growth. Keywords: FFT methods, phase-field fracture, crystal plasticity, fatigue indicator parameters, polycrystals 1. Introduction Fatigue damage in metal alloys is arguably the biggest threat to the service life of engineering components [1]. Service life predictions are thus dependent on our ability to model the various stages of fatigue damage, from the nucleation of a fatigue crack to its propagation and unstable failure [2]. In many applications and sectors, such as the aeronautical or automotive industries, the formation of a macroscopic crack corresponds to a very significant portion of the fatigue life. Hence, being able to predict the stages of fatigue crack nucleation and short crack growth is of notable scientific and technological importance. However, these early stages of fatigue damage are very microstructurally-sensitive [3], partially explaining the observed variability in fatigue lives [4, 5], * Corresponding authors Email addresses: [email protected] (S. Lucarini), [email protected] (E. Mart´ ınez-Pa˜ neda) Preprint submitted to International Journal of Fatigue April 4, 2023 arXiv:2304.01125v1 [cs.CE] 3 Apr 2023
An FFT-based crystal plasticity phase-field model for micromechanical fatigue cracking based on the stored energy density
May 21, 2023
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