Fatigue reference information

Rubbing between the chain or sprockets and other objects can canse nnnsual wear. Impact between the chain and a solid object can cause the chain to break from fatigue. Refer to Table 15-1 for more information. 

Her research into heart failure has given her some information about what types of variables she should collect. Patients with heart failure show symptoms of decreased exercise tolerance, shortness of breath, increased fatigue, and fluid buildup in the lungs and tissues. Patients with heart failure are also classified clinically by their level of disability so that they may be followed longitudinally and provide a reference point when compared with other patients. This classification system is the New York Heart Association (NYHA) Functional Classification system and ranges from functional class I (no limitation of physical activity) to functional class IV (unable to carry on physical activity without discomfort) (Criteria Committee, 1973). 

Yet another variation of this test, which is also used to obtain creep information, is to simply attach a load to a specimen and measure its time to failure. The results are then plotted in a format identical to the one shown in Fig. 12.1 la for cyclic fatigue, and are referred to as static fatigue or stress/life curves. 

For additional information regarding designing pressure vessels for fatigue see Reference 7, Chapter 5. 

A subsequent investigation conducted by the Norwegian government concluded that the rig collapsed due to a fatigue crack in one of the rig s six bracings (bracing D-6), which connected the collapsed D-leg to rest of the rig [3,20]. Additional information on this accident is available in References 3,10, and 20. 

It is to be noted that among the nondestructive methods for fatigue damage imitation assessments, x-ray diffraction method is considered to be one of the most suitable analysis methods [14]. Additional information on this method is available in Reference 14. 

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