ABSTRACT
The model of fatigue crack growth developed is related to classical models of linear fracture mechanics supplemented with effects of modeling of microdamage accumulation. Elasto-plastic fracture is the subject of nonlinear fracture mechanics. In fatigue, the models of nonlinear fracture mechanics are complicated not only by the necessity to include microdamage accumulation. Considering cyclic elasto-plastic straining, one must take into account hysteretic phenomena as well as cyclic softening and/or hardening. During crack propagation, stress distribution changes; however, the process zone length remains one of the leading parameters for fatigue growth in elasto-plastic materials. The thin plastic zone model has been used in this chapter to predict crack initiation and growth in elasto-plastic materials. Being comparatively simple, this model allows various generalizations that are necessary in fatigue analysis to include the influence of damage accumulation on material properties.
