Fatigue parameters

Bugyi, G. J., The effects of moderate doses of caffeine on fatigue parameters of the forearm flexor muscles, American Corrective Therapy Journal, 34, 49, 1980. 

Both Ki and K2 are fatigue parameters which vary with the composition of the asphalt mixture. Figures 2 and 3 present the variation of Ki... 

In building the task network model, one can build functions to degrade a specific task s performance through an arithmetic weighting of sldll-degradation multipliers that are derived from the degradation functions. For example, if the fatigue parameter was time since sleep and the value of that parameter was 36 hours since sleep, the task time performance multipliers would be as follows in the example above ... 

Three example problems are shown 1) A disk in thermal shock to illustrate fast-fracture transient analysis, 2) a diesel engine exhaust valve to contrast predictions for cyclic loading and proof testing, and 3) the hypothetical effect of changing Weibull and fatigue parameters over time on the reliability of alumina flexure bars in static... 

Most of the terms in these equations are functions of and t. The fatigue parameter B has units stress x time. Y is the crack geometry correction factor, Kic is the critical mode I stress intensity factor, and dil = sin adad(J. The term aieq,k,Tmax represents the effective stress examined over k time steps (entire load history) which yields the highest fast-fracture failure probability. It can be computed by... 

The Heaviside function H( ) in Eq. (17) was originally used in Nemeth et al. for static (non-time-varying loads) loads and constant Weibull and fatigue parameters. Its use here requires expressing variables in terms of equivalent peak statie loads and equivalent times. Equivalent time is the comparable time interval for a static applied load that has the same amount of crack growth (or same reliability) as the transient load (load varying with time) situation. The Heaviside function H( ) in Eq. (17) is used where... 

Table 2. Weibull and fatigue parameters associated with Figure 10.

C. Jarbouh, V PeUerin, D. Treheux, and L. Vicent, Study of the Fatigue Parameters of Titanium Alloys Treated for Wear Resistance, Sixth World Conference on Titanium (France), 1988, p 1859-1864... 

This study has used multiple fatigue parameters to verify that the subjects are physically fatigue. All the three parameters seem to relate to one another very well. Generally, the subject s performance started deteriorating since the first trial and stabilizes at around the 15th trial. 

FIG. 11 Important fatigue parameters are defined on a schematic hysteresis loop. is the maximum compressive stress, tensile stress, Asi is the total strain range, and Aet, is the hysteretic strain range. 

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