FBG-based ultrasonic wave detection and acoustic emission linear location system

The ultrasonic (US) wave detection and an acoustic emission (AE) linear location system are proposed, which employ fiber Bragg gratings (FBGs) as US wave sensors. In the theoretical analysis, the FBG sensor response to longitudinal US wave is investigated. The result indicates that the FBG wavelength can be modulated as static case when the grating length is much shorter than US wavelength. The experimental results of standard sinusoidal and spindle wave test agree well with the generated signal. Further research using two FBGs for realizing linear location is also achieved. The maximum linear location error is obtained as less than 5 mm. FBG-based US wave sensor and AE linear location provide useful tools for specific requirements.