Effect of Hydrostatic Stress on Low Cycle Fatigue Life

This paper overviews the effect of hydrostatic stress on the static tensile stress-strain relationship, low cycle fatigue life, creep rupture time and creep-fatigue life at room and elevated temperatures. There was almost no influence of the hydrostatic stress on the tensile stress-strain relationship but the tensile ductility was increased by the hydrostatic stress. Small or little increase of fatigue life was observed by the superposition of the hydrostatic stress under a full reversed loading but a clear increase of fatigue life was found in a zero-to-tension loading. The hydrostatic stress significantly lowered the creep strain rate and elongated the creep rupture time. The hydrostatic stress also increased the creep-fatigue life under a full reversed loading.