Fatigue of engineering materials

Abstract

Scope of Study: Investigation of the fatigue properties of engineering materials has formed the basis of much study in the past one hundred years. Although the approach to many of the studies were very similar, the results contain a large degree of variance. In order to reduce the variation in test results and to obtain data which is useful, a study of previous work in this area has been made. Particular emphasis has been placed on planning of fatigue test programs, variables which must be considered, and methods of handling fatigue test data. Materials used were chiefly papers presented to national organizations, such as the American Society of Mechanical Engineers, Institution of Mechanical Engineers, and The International Union of Theoretical and Applied Mechanics.

Findings and Conclusions: The variation in fatigue test data is primarily due to three factors: (1) the large number of variables involved, (2) the difference in test procedures, and (3) improper planning of fatigue test programs. In order to obtain useful data, it is essential that these three factors be evaluated to the greatest possible degree. The prediction of the service life of any member subjected to fatigue loads cannot be accurately done by use of static properties.

The extreme cost of fatigue test programs has retarded the advancement of investigation into fatigue properties of engineering materials to a great degree. Therefore, at the present time, little if any information is available on materials other than steels and certain aluminum alloys. This is due to the fact that these are the only materials which industry has subjected to fatigue loads.