Several methods proposed for the treatment of mean stress effects on time-independent low cycle fatigue (LCF) lifetime were critically evaluated using LCF crack initiation data on a number of materials used in gas turbine design. The methods evaluated included Jaske’s equivalent strain (εeq) formulation, Manson ’s mean stress correction method and nonlinear Goodman diagram representation of the strain-controlled LCF data. LCF crack initiation data on STA Ti-6-4 (533K), Ti-5522S (783K), IN-706 (866K) and MAR-M246 (1033K) were utilized in the evaluations. The evaluations were carried out in terms of each method’s capability to back-predict the experimetnal data used in its construction. Also considered were the implications associated with the type and the extent of data required for each method.

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