Optimization of Environmental Fatigue Evaluation: Step 2

In order to introduce environmental effects into fatigue evaluation of design and construction codes, the environmental fatigue evaluation method should not only be established, but the conservativeness of the codes, design transient conditions and so on should also be reviewed. The former paper [1] presented in 2007 ASME Pressure Vessels and Piping Conference reviewed and discussed design factors of design fatigue curves, design transient conditions, stress analysis techniques and environmental fatigue evaluation methods. In this paper, rationalization of typical design transient conditions is discussed and design factors of a design fatigue curve for austenitic steels are studied. Rationalized numbers and/or conditions are proposed for the typical design transients that are dominant for fatigue evaluation. A mean fatigue curve of austenitic steels is analyzed by using a statistical method with the latest data. The design factors of the fatigue curve of austenitic steels are investigated for parameters decreasing fatigue life such as size effect, surface finish and data scatter and appropriate design factors are proposed. Future studies are discussed.Copyright © 2009 by ASME