Bending strength and static fatigue of glass fibre in different atmospheres by fibre loop test

This study deals with the dependence of glass-fiber bending strength and static fatigue on different factors, mainly the ambient atmosphere. The fracture diameter of a loop (as measured by the loop test), which is proportional to the bending strength, was found to be dependent on the diameter of the fiber, as well as on the water concentration of the ambient atmosphere. Heat treatment did not increase the bending strength of the fiber. High-temperature treatments decreased the bending strength of the fiber substantially. The results showed this to occur in a wide temperature range, whereas in massive glass relaxation has also been found in a wide temperature range. Under long-term stress, the fibers are affected by static fatigue, which is dependent on the diameter of the fiber, the effective force, and the ambient atmosphere.