A General Fatigue Evaluation Method (Elastic Stress or Plastic Strain with Constant or Varying Principal Direction)

A method is proposed for ASME Section III fatigue evaluations which can be applied in the elastic or plastic ranges with constant or varying principal stress/strain directions. The generality of the method is demonstrated. For biaxial or triaxial loadings, the method is shown to be more consistent than the Code procedure given in NB-3228.1.