INFLUENCE OF AN OVERLOAD ON THE FATIGUE CRACK GROWTH IN STEELS

Abstract— This study is concerned with the influence of a single-peak overload and the overload ratio on the subsequent rate of growth of a fatigue crack in steels. Retardation increases with increasing overload ratio.
The crack opening load was also measured during all tests. It is shown that the Elber's crack closure concept is not able to explain the effect of overloads. The importance of the material yield stress was evaluated by testing steels of different strength. It seems that the residual stress state induced by the overload is the major factor causing retardation. Two models are analyzed.