Cyclic response and inelastic strain energy in low cycle fatigue

The cyclic response of ASTM A-516 Gr 70 carbon low alloy steel subjected to fully-reversed constant strain- or stress-controlled cycles has been determined. The cyclic stress/strain relationship of the material was obtained through a least squares fit technique. Stable hysteresis loops at half life for various strain ranges are presented. The material does not exhibit Masing-type behaviour. The total inelastic strain energy is calculated by a new method and is in good agreement with the measured values. Comparison is also made with other proposed relationships. The total strain energy dissipated at failure may be expressed as Wf = KNfα