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Mechanically small cracks

Fatigue crack nuclei that precede macro crack formation originate in persistent slip bands well before the final failure. It has been said in 1.4.1 that they start to appear on the surface of the material as soon as the hardening/softening process saturate and, in fact, it has been also said that if the cyclic hardening were periodically removed by annealing the specimen subjected to a fatigue test, the life of the specimen would increase enormously to almost become infinite. Saturation [Pg.45]

The basic assumptions of fracture mechanics are (1) that the material behaves as a linear elastic isotropic continuum and (2) the crack tip inelastic zone size is small with respect to all other dimensions. Here we will consider the limitations of using the term K = YOpos Ttato describe the mechanical driving force for crack extension of small cracks at values of stress that are high with respect to the elastic limit. [Pg.494]

The few studies which addressed the fracture mechanics behavior of very small cracks generally revealed a quantitative departure from behavior determined at longer crack lengths. This result may be attributed to a departure from perfect mechanical and microstructural similitude between long and small cracks. [Pg.497]

Analogous to the arguments of small-scale yielding in linear elastic fracture mechanics, small-scale creep conditions (i.e., the situation where the size of the creep zone ahead of the fatigue crack tip is small compared to the characteristic dimensions of the test specimen, including the size of the crack and that of the uncracked liagment) can be assumed to exist when... [Pg.232]

Fig. 28. Micrographs of a fractured specimen, showing numerous small cracks on the gauge length (enlarged in (b)), and intergranular fracture (c) enlargement of fracture surface [57]. Copyright 1991. Electric Power Research Institute/EPRl ER-7247. Intergranular Corrosion of Stainless Steel. Vol. 1 Mechanism of Crack Initiation. Reprinted with permission. Fig. 28. Micrographs of a fractured specimen, showing numerous small cracks on the gauge length (enlarged in (b)), and intergranular fracture (c) enlargement of fracture surface [57]. Copyright 1991. Electric Power Research Institute/EPRl ER-7247. Intergranular Corrosion of Stainless Steel. Vol. 1 Mechanism of Crack Initiation. Reprinted with permission.
See other pages where Mechanically small cracks is mentioned: [Pg.29]    [Pg.45]    [Pg.46]    [Pg.47]    [Pg.49]    [Pg.51]    [Pg.53]    [Pg.55]    [Pg.57]    [Pg.59]    [Pg.61]    [Pg.62]    [Pg.63]    [Pg.65]    [Pg.67]    [Pg.610]    [Pg.852]    [Pg.29]    [Pg.45]    [Pg.46]    [Pg.47]    [Pg.49]    [Pg.51]    [Pg.53]    [Pg.55]    [Pg.57]    [Pg.59]    [Pg.61]    [Pg.62]    [Pg.63]    [Pg.65]    [Pg.67]    [Pg.610]    [Pg.852]    [Pg.53]    [Pg.497]    [Pg.1155]    [Pg.1256]    [Pg.674]    [Pg.674]    [Pg.31]    [Pg.517]    [Pg.518]    [Pg.47]    [Pg.412]    [Pg.112]    [Pg.198]    [Pg.99]    [Pg.496]    [Pg.497]    [Pg.30]    [Pg.401]    [Pg.192]    [Pg.406]    [Pg.6]    [Pg.281]    [Pg.394]   
See also in sourсe #XX -- [ Pg.29 , Pg.45 , Pg.61 ]



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