An accelerated phase field model for fatigue fracture in elastoplastic solids
摘要
It is time-consuming to simulate fatigue fracture cycle by cycle with the phase field model for elastoplastic materials. To address this challenge, this work develops an acceleration scheme for ductile fatigue fracture in elastoplastic solids based on a concurrent time-scale homogenization scheme. The scheme decomposes the fatigue fracture problem into a macrochronological problem and a microchronological one, and accelerates the simulation by adaptively determining the macrochronological time steps. The macrochronological time step is adjusted by a predictor-corrector strategy. This strategy is able to capture the regime changes of the fatigue process. Two additional innovative ingredients are: Firstly, the time step determination and predictor-corrector strategy are both based on two key history fields (KHFs) that quantify elastic and plastic effects. Secondly, a delicate scheme to differently extrapolate the history fields (the two KHFs and three other history fields) is developed to ensure the macrochronological problem is properly solved. Through displacement- and force-controlled simulations, the ability of this scheme to accelerate the simulations for fatigue fracture coupled with cyclic plasticity up to ten times with reasonable accuracy is demonstrated. Moreover, the proposed scheme predicts faster crack growth than direct numerical simulations, offering a conservative estimate for the fatigue life.
Graphic Abstract