주조 알루미늄합금 A356의 저주기 피로특성 및 피로수명 모델

다국어 초록 (Multilingual Abstract)

Low cycle fatigue characteristics of cast aluminum alloy A356 with a yield strength and ultimate strength of 229 and 283 MPa respectively was evaluated using smooth axial specimen under strain controlled condi-tion. Reversals to failure ranged from 16 to 10^7. The cast aluminum alloy exhibited cyclically strain-hardening behavior. The results of low cycle fatigue tests indicated that the conventional low cycle fatigue life model was not a satisfactory representation of the data This occurred because the elastic strain-life curve was not log-log linear and this phenomena caused a nonconservative and unsafe fatigue life prediction at both extremes of long and short lives. A linear log-log total strain-life model and a bilinear log-log elastic strain-life model were proposed in order to improve the representation of data compared to the conventional low cycle fatigue life model.<br/>
Both proposed fatigue life models were statistically analyzed using F tests and successful1y satisfied. However, the low cycle fatigue life model generated by the bilinear log-log elastic strain-life equation yielded a discontinuous curve with nonconservatism in the region of discontinuity. Among the models examined, the linear log-log total strain-life model provided the best representation of the low cycle fatigue data Low cycle fatigue life prediction method based on the local strain approach could conveniently incorpo-rated both proposed fatigue life models.<br/>