Comparing polymer optical fiber, fiber Bragg grating, and traditional strain gauge for aircraft structural health monitoring

Systems for structural health monitoring in aeronautical structures use methods of measuring the elongation that normally require too heavy setups or difficult assembly jobs, such as those based on traditional strain gauges. Alternative methods based on fiber Bragg gratings tend to be very expensive. We analyze the possibility of improving the existing designs with the aid of low-cost plastic optical fiber sensors. For this purpose we test these sensors in a rudder flap subjected to different types of bending forces. The results show that they offer good stability and repeatability, and the measured values are very similar to those obtained with Bragg sensors.