STATISTICAL-ANALYSIS OF FIBER FAILURES UNDER BENDING-STRESS FATIGUE

We have analyzed the failure data of a standard telecommunication opti cal fiber under static bending stress. Experimental data have been col lected on a 468 day period, observing more than 7000 turns, with a ben d radius ranging from 1.25 to 6 mm. The statistical analysis has been carried out by both the least-square and the maximum likelihood method . We have found that data are fitted by a Weibull distribution, as exp ected theoretically. Moreover, we have determined the scale and shape parameters and tested their dependence on the bend radius. According t o our results, we conclude that in sensor applications silica fibers c an be safely bent down to a radius less than 5 mm.