Fatigue Criteria Under Combined Stresses or Strains

Abstract
A brief presentation is given of a previously proposed criterion for long-life fatigue under combined alternating and combined static stress. A new criterion is proposed for long-life fatigue under high static stress. Generalizations are made on criteria for low-cycle fatigue under combined stress and the form that these criteria take in principal stress space. Speculations are made on a possible criterion for fatigue under variable phasing between the principal stress amplitudes.