Plastic optical fibre sensor for structural health monitoring

Abstract

Plastic optical fibre sensors offer remarkable ease of handling and recent research has shown their potential as a low-cost sensor for damage detection and structural health monitoring applications. This paper presents details of a novel plastic optical fibre sensor and the results of a series of mechanical tests conducted to assess its potential for structural health monitoring. The intensity-based optical fibre sensor proposed in this study relies on the modulation of light intensity as a function of a physical parameter (typically strain) as a means to monitor the response of the host structure to an applied load. Initially, the paper will reveal the design of the sensor and provide an summary of the sensor fabrication procedure followed by an outline of the experimental programme conducted in this study. Two types of sensor design will be evaluated in terms of their strain sensitivity, linearity and signal repeatability. Results from a series of quasi-static tensile tests conducted on aluminium specimen with four surface-attached optical fibre sensors showed that these sensors offer excellent linear strain response over the range of the applied load. Free vibration tests based-on a cantilever beam configuration were also conducted to assess the dynamic response of the sensor. The results demonstrate excellent agreement with conventional sensor readings.