The use of plastic optical fibre sensors for monitoring the dynamic response of fibre composite beams

This paper reports the findings of an evaluation of a low-cost, intensity-based plastic optical fibre (POF) sensor for monitoring the dynamic response of both cantilever and simply supported beams subjected to dynamic loading conditions. The sensors were either surface bonded to a plastic beam or embedded in a carbon-fibre composite and subjected to a series of forced and free vibration tests to assess the ability of the sensors to monitor these dynamic events. In the free vibration tests, the natural frequencies of the beams based on the results of the POF sensor were found to compare well with the predicted theoretical values as well as the readings obtained from an electrical strain gauge. Impact tests on simply supported carbon-fibre reinforced beams demonstrated the sensor's ability to monitor out-of-plane deflections during the impact event. A laser Doppler velocimeter was also used in conjunction with a piezoelectric load cell as a means to validate the results of the POF sensor.