PREDICTION OF TIME TO FAILURE FOR OPTICAL FIBRES UNDER THERMO-MECHANICAL STRESSES.

Considering measurement accuracies, different models used for the prediction of longterm static fatigue for optical fibres under stress were studied. Optical fibres were wound onto an alumina mandrel with various diameters and immersed in hot water at different temperatures. The determination of model parameters was based on the fit of experimental data to model expressions relating time to failure, applied stress and environmental conditions. It is shown that the differences in allowed stress predictions between models become quite close at short times. The time-to-failure depends on the applied stress applied but also and above all on the ageing temperature and the humidity level. Results from tested fibres indicate a clear strength reduction with increasing temperature or applied stress. [ABSTRACT FROM AUTHOR]