General Fatigue Behavior

General Fatigue Behavior of Unidirectional Ceramic Niatrix Composites... 

High temperature fatigue and fretting fatigue behavior has also been improved by implantation (113,114). This has been achieved by using species that inhibit oxidation or harden the surface. It is generally accepted that fretting behavior is closely coimected to oxidation resistance, perhaps due to third party effects of oxidation products. Oxidation resistance alone has also been improved by ion implantation (118—120). 

When compared to monolithic and whisker-reinforced ceramics, the fatigue behavior of fiber-reinforced ceramics exhibits several unique features. For example, the fatigue failure of monolithic ceramics generally occurs by the... 

Since engineering plastics are often subject to cyclic or repeated stresses, the question of fatigue behavior is important. In general, relatively little attention has been given this phenomenon in plastics, with the exception of measurements of lifetime as a function of stress, frequency, and number of... 

One of the earliest attempts to describe the fatigue behavior of materials in general is referred to as the Paris Law (66-68). The Paris Law is an empirical relationship that exists between the crack growth rate dC/dN and the change... 

Confirmation of the general fatigue superiority of semicrystalline polymers is implicit in studies of a-N behavior at frequencies low enough to minimize temperature rises (169). While the ratios of the endurance limit to tensile strength for typical amorphous polymers (polystyrene, PMMA, and cellulose acetate) are approximately 0.2, values for nylon-6,6, acetal resin, and polyterafluoroethylene are 0.3, 0.5, and 0.5, respectively. At a low frequency, polyethylene (Mw > 50,000) exhibits no failure after 5 x 10 cycles, even at the relatively high alternating stress... 

Various criteria are utilized to describe fatigue behavior under dynamic load that are generally derived from the intended application ... 

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