高周疲劳裂纹萌生的非线性微观力学模型

简要介绍了高周疲劳裂纹萌生的微观力学模型，如滑移带挤出模型，位错塞积模型和位错反应模型等。

An Nonlinear Micromechanics Models of the Fatigue Crack Initiation under High Cycles

The micromechanics models of fatigue crack initiation under high cycles are briefly reviewed, i.e., the slip band extrusion intrusion model, dislocation blocking mo del and dislocation reaction model. Most of these models show that shear stress within the fatigue failure zone controls the initiation of fatigue cracks. Among these models, the most typical model is the linear dislocation dipole model of the slip band extrusion intrusion model, which shows that the dislocation number in the crystalline grains increases li nearly with the fatigue loads. By the fatigue experiment and micro metallographic analysis, it is found that the dislocation number in the crystalline grains increases nonlinearly with the fatigue loads and an improved nonlinear dislocation dipole model is put forward based on the linear dislocation dipole model. By the contrast between the experiment and the simulated calculation, it is found that this model is more coincidental with the experimental results.