In order to examine the feasibility of using plate-type waveguides for the effective detection of acoustic emissions (AEs) from the termite attack in wood, AEs generated by breaking pencil leads or termite attack were detected using an AE sensor with a resonant frequency of 140kHz with steel plates of four different sizes and thickness and three AE sensors without them. Larger plates were associated with larger amplitudes of the artificial AEs. The amplitudes of AEs detected by and AE sensor with a steel plate larger than 30 by 30mm were greater than the average amplitude of the artificial AEs detected by three AE sensors. In detecting AEs generated by the feeding activity of workers, Coptotermes formosanus Shiraki,the cumulative AE events detected by the sensor with a steel plate were much larger than those of the three AE sensors without a plate. Since AE waves are attenuated much less in a steel plate than in wood, it is more effective to attach the AE sensor to wood with a steel plate rather than directly to the wood. These findings suggest that it is feasible to use an AE sensor with a plate-type waveguide for the nondestructive detection of termite attack in wood.
Back to Projects