Interfacial shearing stress in pull-out testing of dual-coated lightguide specimens

A simple analytical model is developed for the evaluation of the interfacial shearing stress at the glass fiber surface in dual-coated optical fiber specimen subjected to tension. It is shown that the distribution of this stress is nonuniform and that, for the given specimen´s length, its maximum value increases with a decrease in the thickness of the primary coating. The obtained results can be useful for comparing the adhesive strength of the primary coating material in fibers of different lengths and with different coating designs, as well as for the in situ evaluation of Young´s (shear) modulus of this material from the measured axial displacement of the glass fiber