Statistical analysis of fiber failures under bending-stress fatigue

We have analyzed the failure data of a standard telecommunication optical fiber under static bending stress. Experimental data have been collected on a 468 day period, observing more than 7000 turns, with a bend 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 expected theoretically. Moreover, we have determined the scale and shape parameters and tested their dependence on the bend radius. According to our results, we conclude that in sensor applications silica fibers can be safely bent down to a radius less than 5 mm.