Abstract
It is well-known that one of the major characteristics of variable fatigue loads, especially overloads, is the retardation of the fatigue crack due to the complex interaction of many factors such as the overload ratio, the timing of overloads, the stress ratio, the yield stress of the material, the thickness of the structure, and the stress history. However, studies of the combined effect of mixed-mode I+II constant amplitude fatigue loadings and a mixed-mode I+II single overload on fatigue behavior are still scant. In this study, fatigue tests were conducted under mixed-mode I+II constant amplitude loadings with a mixed-mode I+II single overload, with reference to the variation of fatigue crack retardation. The formation of the overload plastic zone (OPZ) ahead of the crack tip under a mixed-mode I+II single overload is studied experimentally by the measurement of the shape and size of the OPZ. The behavior of fatigue crack propagation under mixed-mode loading conditions is examined by changing the loading mode of a single overload, and the relationship between the mixed-mode I+II single overload and the behavior of fatigue crack propagation in terms of the characteristics of the OPZ is evaluated. The empirical modeling of the fatigue life under mixed-mode I+II constant amplitude loadings is proposed by considering the characteristics of both the OPZ and the combination of the mode-mixity of mixed-mode I+II constant amplitude loadings and a mixed-mode I+II single overload.
Original language | English |
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Pages (from-to) | 1848-1857 |
Number of pages | 10 |
Journal | International Journal of Fatigue |
Volume | 31 |
Issue number | 11-12 |
DOIs | |
Publication status | Published - 2009 Nov |
Bibliographical note
Copyright:Copyright 2009 Elsevier B.V., All rights reserved.
Keywords
- Fatigue crack propagation
- Fatigue life
- Mixed-mode I+II
- Retardation
- Single overload
ASJC Scopus subject areas
- Modelling and Simulation
- General Materials Science
- Mechanics of Materials
- Mechanical Engineering
- Industrial and Manufacturing Engineering