2016 Volume 2 Pages 16-00502
In the energy sector, structures such as offshore wind power plants typically operate for long periods of time in harsh environments. Therefore, remote monitoring systems are required for maintenance. Optical fiber sensors are suitable for this purpose because the transmission loss in the optical fiber lines is very small. For the optical fiber sensor is small transmission loss, the measurement data can be far transmission. Therefore, optical fiber sensing systems are widely used to monitor the structures of wind power plants. Wind power generation systems contain many rotary shafts that are constantly subjected to severe operating loads. It is important to maintain rotary shafts and other rotating components. Their health can be monitored by measuring the strain in the rotary shaft. Optical fiber sensors are line sensors that have a length of measuring section. However, the effects of surface curvature, such as that of a rotary shaft, on the measured strain are not known in detail. These sensors are considered more susceptible to the effects of curvature than conventional point sensors. Therefore, the effect on strain measurement accuracy must be determined. In this study, a high-precision torsional strain sensor system is proposed that uses a fiber Bragg grating (FBG)optical fiber sensor. Torsional load tests were conducted to confirm the effects of curvature on the strain distribution measurement and the performance of the FBG sensor attached to the cylindrical shaft. The proposed measurement technique was evaluated for measurement of the torsional strain distribution and temperature. Experimental and FEM analysis results were compared to verify the measurement accuracy.
