Distributed strain measurement using optical fiber sensor with high spatial resolution

초록

The distributed sensor system is constructed to measure local Brillouin gain spectra to realize the concept of the BOCDA and strain distribution of a joint composite specimen is acquired. Distributed measurement is performed by sweeping both frequency difference and the modulation frequency, and the obtained information of the Brillouin frequency variation is converted into strain or temperature at each point. Strain distribution of a 41 cm surface of T joint was acquired when the vertical load was applied on the T joint. The spatial resolution of the strain measurement was 1.5 cm. The measurement of the strain distribution in this experiment can be used to verify the T joint design and to detect the fracture at the corner.