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Development of Fatigue Properties Database for Use With Modern Design Methods (06-07#02) |
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Coordinator
Stork Climax Research Services Strain-life fatigue testing has evolved into a mature practice over the last several decades. In recent years, endurance modeling and design techniques have been developed to utilize strain-life fatigue data. The older stress-controlled fatigue testing, with its focus on identifying an endurance limit, is inadequate for computer aided design. While a recent AFS sponsored survey of the open literature revealed an abundance of stress-life fatigue data for cast irons, the necessary strain-life data were reported for only a few grades of cast iron. In the absence of the appropriate fatigue data, designers can be confronted with the choice of creating relatively inefficient designs with large factors of safety, or simply excluding cast iron from their design considerations. The proposed overall program will develop a comprehensive strain-life database for cast irons by combining data obtained from the open literature with unpublished data contributed by cast iron producers and end-users. The proposed program will also supplement these data by a focused program of strain-life testing to fill the gaps in the data. The current activity is for two cast iron grades in the matrix of cast irons that have been proposed for the strain-life data base. These are: Austered Ductile Iron 750 Material and 60-40-18 heavy section ductile iron. The enhanced design capabilities made possible by this database will benefit end-users by improving their design options (allowing them to consider cast iron in new applications; by facilitating the design of more efficient (lighter/smaller) components along with product testing and development. Benefits to the foundry industry would arise from both new and expanded markets for their products. Furthermore, a reduction in national energy expenditures is expected from a reduction in foundry energy consumption for the production of more efficiently designed components. A further energy saving would result from the choice of cast iron in component design rather than selecting materials fabricated using less energy efficient processes. Finally, a reduction in environmental contamination (particularly greenhouse contaminants) is expected to result from the decreased use of energy derived from fossil fuels.
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