Abstract
Procedure to analyze the crack initiation under strain path changed during multiaxial low cycle fatigue is developed based on a damage mechanics approach. The fatigue tests of pure copper are conducted to investigate the crack initiation behavior for changing biaxial strain ratio during low-cycle fatigue. The parameter referred as the intensity of slip band is used to describe the oriented distribution of slip band and the crack initiation life depending on the strain biaxiality. A model for the crack initiation under multiaxial stress states is proposed assuming the non-linear accumulation of the intensity of slip band. The estimation based on the proposed model showed a good agreement with the experimental results when compared with the result by Miner's law.
