Development and characterisation of fibre-optic acoustic emission sensors
J O Willberry, G Fernando and M Papaelias
School of Metallurgy and Materials, The University of Birmingham, Birmingham, UK
Email: jow743@bham.ac.uk
Acoustic emission (AE) is widely used for condition monitoring of critical components and structures. Conventional AE monitoring techniques use either wideband or resonant piezoelectric sensors to detect elastic stress waves emitted from a source (for example a propagating crack). Piezoelectric AE sensors are mounted on the surface of the structure to be monitored and held in place using magnetic hold-downs or adhesive tape. Coupling is achieved with the use of an appropriate ultrasonic couplant. Piezoelectric sensors tend to be relatively bulky so they cannot be embedded. In addition, when used in flammable or explosive environments they need to be manufactured as intrinsically safe. Fibre-optic acoustic emission sensors (FOAES) offer several advantages over conventional piezoelectric sensors since they can be embedded and are inherently intrinsically safe since they employ light instead of electricity. This study discusses the approach employed for manufacturing FOAES together with methods used for characterising them. A comparison between reference AE signals captured using conventional piezoelectric sensors and FOAES is provided.
Keywords: acoustic emission, fibre-optic sensors, condition monitoring.
Keywords: acoustic emission, fibre-optic sensors, condition monitoring.
