Sensitivity coefficient evaluation of an embedded fiber-optic strain sensor

A simple model is developed for evaluating the interaction between the surrounding matrix and a length of optical fiber embedded in it. The analysis has been performed for nominal uniform pull-stress applied to the matrix, in which a sensitivity coefficient K(L) is used to describe the percentage of strain applied to the composite actually transferred to the fiber. The theoretical results have shown that the sensitivity coefficient of the fiber-optic strain sensor depends on the embedded length of the optical fiber and the material properties of the fiber coating. The general trend of increasing the sensitivity coefficient with increasing action length has been confirmed by the experimental results. The distributions of interfacial shearing stress between matrix and coating and coating and glass fiber are given. Experiments have been performed using a white-light fiber-optic interferometer. (C) 1998 Elsevier Science S.A. All rights reserved.