Fatigue crack propagation factor

Some other factors, including the metallurgical condition of the material (such as composition and heat treatment) and the loading mode (such as uniaxial), affect corrosion fatigue crack propagation. (Glaeser and Wright)5... 

Fatigue Crack Propagation at Constant Stress Intensity Factor AK. 123... 

FIGURE 7.6 Fatigue crack propagation rate (daldN) vs. stress intensity factor range (AK) relationships measured in low-pressure hydrogen gas for two low-alloy steels with different tensile strengths. " ... 

Fig. 29. Fatigue crack propagation rate da/dN as a function of relative stress intensity factor AK, in different polymers (Hertzberg et al.

Fatigue crack propagation because of cyclic and uneven loading was also a contributing factor. The use of steels of higher toughness with intrinsic weathering resistance has been advanced as a remedial measure. 

Addition of a small amount of core-shell toughening particles of 0.3 pm diameter to a polycarbonate/copolyester blend reduced the fatigue crack propagation rate by a factor >20 and gave rise to significantly more plastic deformation during fitacture [134]. 

The model adequately represents physical processes of the fatigue crack propagation. During the cycling of metal the dislocation density increases by a factor of 3. The vacancy concentration increases by three orders of magnitude. 

Figure 3.22. Relationship between fatigue crack propagation rate per cycle dajdn and the range of applied stress intensity factor AK for various modifications of polystyrene (Hertzberg et a/., 1973). Note the toughening effect of incorporating a rubbery phase, as in HiPS or ABS, compared to the weakening effect of crosslinking.

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