Phase-field framework with constraints and its applications to ductile fracture in polycrystals and fatigue  

作　　者：Fei Xue Tian-Le Cheng Yinkai Lei You-Hai Wen 

机构地区：[1]U.S.DOE National Energy Technology Laboratory,Albany,OR 97321,USA [2]Leidos Research Support Team,Albany,OR 97321,USA

出　　处：《npj Computational Materials》2022年第1期149-163,共15页计算材料学（英文）

摘　　要：Modeling of ductile fracture in polycrystalline structures is challenging,since it requires integrated modeling of cracks,crystal plasticity,and grains.Here we extend the typical phase-field framework to the situations with constraints on the order parameters,and formulate two types of phase-field models on ductile fracture.The Type-Ⅰ model incorporates three sets of order parameters,which describe the distributions of cracks,plastic strain,and grains,respectively.Crystal plasticity is employed within grain interiors accommodated by J_(2)plasticity at grain boundaries.The applications of the Type-Ⅰ model to single crystals and bicrystals demonstrate the influences of grain orientations and grain boundaries on crack growth.In the Type-Ⅱ model,J_(2)plasticity is assumed for the whole system and grain structures are neglected.Taking advantage of the efficiency of the fast Fourier transform,our Type-Ⅱ model is employed to study low cycle fatigue.Crack closure and striation-like patterning of plastic strain are observed in the simulations.Crack growth rate is analyzed as a function of the J-integral,and the simulated fatigue life as a function of plastic strain agrees with the Coffin–Manson relation without a priori assumption.

关 键 词：DUCTILE FATIGUE GRAIN 

分 类 号：TG14[一般工业技术—材料科学与工程]