EFFECTS OF HIGH STRAIN RATE ON LOW-CYCLE FATIGUE BEHAVIOR OF STRUCTURAL STEEL IN LARGE PLASTIC STRAIN REGION

抄録

 This study aims to investigate the effects of very high strain rate on low-cycle fatigue behavior of structural steel under large plastic strain with strain rate order of 1.0 s^-1 as expected during earthquakes. Low-cycle fatigue tests were conducted using compact-tension specimens at various strain rate levels. Fatigue life based on crack size indicated that the higher strain rate caused lower fatigue life in large plastic strain region. The energy approach was employed to clarify the low-cycle fatigue mechanism in this region. Finally, a prediction method for fatigue life regarding high strain rate effect in large plastic strain region is proposed in this study.