Acoustic emission sensor system using a chirped fiber-Bragg-grating Fabry-Perot interferometer and smart feedback...

Area of Science:

• Optoelectronics
• Materials Science
• Sensor Technology

Background:

• Acoustic emission (AE) detection is crucial for structural health monitoring.
• Traditional AE sensors face limitations with large quasi-static strains.
• Fiber-optic sensors offer potential for robust AE detection.

Purpose of the Study:

• To develop and demonstrate a fiber-optic acoustic emission sensor system.
• To enable AE detection in the presence of large quasi-static strains.
• To ensure continuous and uninterrupted AE signal monitoring.

Main Methods:

• A Fabry-Perot interferometer sensor was fabricated using cascaded chirped fiber-Bragg gratings (CFBGs).
• A tunable semiconductor laser was employed to lock onto spectral notches within the CFBG reflection spectrum.
• A feedback control scheme was implemented for rapid (<1 ms) laser relocking to adjacent spectral notches.

Main Results:

• The developed sensor system successfully performed acoustic emission detection under large quasi-static strains.
• The system maintained continuous monitoring by quickly adapting to spectral shifts.
• The fast relocking mechanism (<1 ms) prevented significant disruption of AE signal acquisition.

Conclusions:

• The demonstrated fiber-optic AE sensor system overcomes the limitations of traditional sensors in high-strain environments.
• This technology offers a promising solution for reliable structural health monitoring.
• The rapid feedback control ensures uninterrupted AE signal detection, enhancing monitoring capabilities.