Fatigue Crack Growth Under Stochastic Loading

  • K. Doliński
  • P. Colombi
Conference paper
Part of the Solid Mechanics and its Applications book series (SMIA, volume 47)

Abstract

Load sequence effects are observed in fatigue experiments under variable amplitude loading. The time, called the lifetime, of reaching a given critical length by a macro crack strongly depends on the arrangement of sequence of load maxima, e.g. [Schijve 1973]. Numerous experiments show rapid changes of the fatigue crack propagation rate after a load cycle with maximum of greater magnitude (overload) than the subsequent maxima. The usual change in the Mode I of crack growth is a transient diminution of the crack propagation rate after the overload. This phenomenon is called the retardation of the crack growth. The duration of the retardation phase and the magnitude of the retardation effect depend on many factors including specimen geometry, environmental effects, material properties, the magnitude of the overload and of subsequent extremes. The physical nature of this phenomenon has not been completely explained, yet. Among several mechanisms suggested in the literature the plasticity-induced fatigue crack closure is generally considered as a dominant cause of the retardation, [Shin & Fleck 1987]. Most of the models that are proposed in the literature to predict the fatigue crack growth with regard to the load sequence effects refer to the overload-induced plastic zone and a diminution of the effective stress intensity factor range after an overload, see e.g. [Wanhill & Schijve 1988]. Such a model will be also used in the present paper to assess some probabilistic characteristics of the structural lifetime when a critical fatigue macro crack length defines the structural failure due to stochastic loading.

Keywords

Fatigue Crack Crack Length Fatigue Crack Growth Initial Crack Length Fatigue Crack Propagation Rate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Kluwer Academic Publishers 1996
Kluwer Academic Publishers

Authors and Affiliations

  • K. Doliński
    • 1
  • P. Colombi
    • 2
  1. 1.Institute of Fundamental Technological ResearchCentre of MechanicsWarsawPoland
  2. 2.Department of Structural EngineeringPolytechnic of MilanMilanItaly

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