Senior EngineerNuclear Technology Division, Westinghouse Electric Corp., Pittsburgh, Pa.
Pages: 18 Published: Jan 1983
Fatigue has often been described as the most common cause of failure in engineering structures, and designers have incorporated fatigue considerations for many years. As the state of the art has advanced, the capability has been developed for allowing for the presence of a crack by predicting its growth and calculating the size which could lead to failure. The crack growth testing and analysis procedures are now well developed, and there is little question as to which data are appropriate for use in such an analysis in a dry environment, for any material.
Prediction of the behavior of fatigue cracks in other environments requires many more considerations, and in fact a multidisciplinary approach is called for, involving chemistry, mechanics, and metallurgy. This paper will discuss some of the possible ways in which information from each of these disciplines can be synthesized into an engineering approach to corrosion-fatigue crack growth predictions. Such an approach would require more than simple data collection from tests, because the relationship of the test environment to the actual environment must be established and proper allowance made for any differences. Moreover, since all the environmental and loading conditions that exist in the application are not always possible to address in testing, some consideration of the mechanisms operating in the material and environment of concern is essential to a good engineering approach.
crack growth rates, environmental effects, engineering applications
Paper ID: STP44822S