Polymer-based optical fiber sensors for health monitoring of engineering structures

Abstract

This paper describes the design of an extrinsic optical fibre sensors based on poly(methamethycrylate) for structural health monitoring applications. This polymer-based optical fiber sensor relies on the modulation of light intensity and is capable of monitoring the response of the host structure subjected to either static or dynamic load types. A series of mechanical tests have been conducted to assess the response of the plastic optical fiber (POF) sensor. The readings of the sensors attached to an aluminium bar were found to compare well to electrical strain gauge response. The POF sensors were also attached to rebar concrete beams and exhibited encouraging response under flexural loading. Static and cyclic loading tests were also performed and the sensor was shown to exhibit excellent strain linearity and repeatability. Free vibration tests on a cantilever beam set-up in which the POF sensor was surface-bonded to a composite beam were also conducted. The results obtained highlight the capability of the sensor to accurately monitor the dynamic response of the beam. Impulse-type dynamic response of the sensor was also conducted and the POF sensor demonstrated potential for detecting the various modal frequencies of the host structure. POF sensors were also attached to a series of impacted composite beams with varying degree of damage to assess their potential to detect and quantify the damage in the host structure. The results demonstrated the feasibility of using the sensor for structural health monitoring applications.