Field Theory-based Multiscale Modeling for Fatigue Crack Initiation process

本研究尝试基于多尺度塑性场理论（FTMP）对滑移带到疲劳裂纹的瞬态过程进行建模和仿真，重点研究了循环应变过程中位错子结构的演变。通过在晶体塑性有限元模拟中引入的基于ftmp的不相容模型，成功地再现了具有阶梯状结构的持久滑移带（PSB）。在确定了PSB阶梯壁结构在空位流中的重要作用后，对过渡过程进行了初步模拟，并引入了空位场的不相容模型。在靠近PSB边缘的试样表面上观察到表面沟槽的形成和扩展，表明在连续的应变循环下，其进一步演变为裂纹。

This study attempted modeling and simulation of a transient process from a slip band to a fatigue crack based on Field Theory of Multiscale Plasticity(FTMP), focusing on the dislocation substructures evolving during cyclic straining. A persistent slip band(PSB) with ladder-like structure was demonstrated to be successfully reproduced via FTMP-based incompatibility model introduced in a crystal plasticity-based FE simulation. After identifying the substantial role of the PSB ladder wall structure in the vacancy flow there, a preliminary simulation for the transition process was conducted, where the incompatibility model for the vacancy field was additionally introduced. There observed surface groove formation and its growth on the sample surface near the edge of PSB, implying its further evolution into a crack under successive straining cycles.