Application of fracture-mechanics theory to fatigue failure of optical glass fibers

The fatigue behavior of optical glass fibers was determined in air at 23°C and 55% relative humidity by the dynamic-fatigue test technique in which strength is measured as a function of stressing rate. The good correlation found between the fatigue test data and fracture-mechanics theory indicates that failure is controlled by slow crack growth of preexisting flaws and that fracture-mechanics theory can be used in making failure predictions for optical glass fibers.