SEDL / STP / STP942-EB / STP24494S

Comparison of Creep-Fatigue Life Prediction by Life Fraction Rule and Strainrange Partitioning Methods

Yamauchi, M
Mitsubishi Heavy Industries, Ltd., Nagasaki Research and Development Center, Nagasaki,

Igari, T
Mitsubishi Heavy Industries, Ltd., Nagasaki Research and Development Center, Nagasaki,

Setoguchi, K
Mitsubishi Heavy Industries, Ltd., Nagasaki Research and Development Center, Nagasaki,

Yamanouchi, H
Choryo Engineering Company, Ltd., Nagasaki,

Pages: 15    Published: Jan 1988

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Abstract

A comparison of two kinds of creep-fatigue life prediction methods, Life Fraction Rule and Strainrange Partitioning, was performed for the cases of creep-fatigue tests under uniaxial strain-controlled conditions at 500 to 600°C in air, using a normalized and tempered 2 1/4Cr-1Mo steel. The main focus was on the influence of stress-strain behavior on life prediction. Two kinds of stress-strain values (i.e., experimental values and calculated values by inelastic analysis) were used for the life prediction of creep-fatigue tests. The results show that life prediction by the Life Fraction Rule was very sensitive to the stress-strain values, indicating a large discrepancy between predicted and observed lives in some cases, and that life prediction by the Strainrange Partitioning method was not so sensitive to the stress-strain values, indicating a good agreement between predicted and observed lives in all cases.