OS12W0362 Study on the low cycle fatigue crack growth problem under mode I+II mixed mode condition

Abstract

The fatigue crack growth test under mode II dominant condition is conducted. It is found that the crack growth direction can not be predicted by the conventional method. By the fracture surface observation, it is also found that the three dimensional effect strongly affects this behavior. Three dimensional elastic-plastic FEM analyses are conducted for this problem considering the Bauschinger effect. The change of the crack tip field during fatigue crack growth is studied. The criteria to predict the fatigue crack growth direction is studied and a new criteria is discussed.