The observed CWT spectrogram shows that L(0,1) mode has a nearly constant velocity to 450 kHz, the primary frequency range of their [A.sub.0]-mode plate wave
. For this range, this wire size gives good reproduction of input waveforms.
Anttila, "On the verification of the applicability of the orthotropic plate wave
theory to paper", Ultrasonics, vol.
This method involves acoustically coupling a transducer to a porous film, producing a plate wave
in the porous film and generating a signal characteristic of the film.
The plate wave
velocities within the composite plates were found by measuring the time taken for the waves to propagate along a 10 cm distance through the plate, Two surface mounted sensors were situated 10 cm apart and a lead break was made on the surface of the plates 10 cm away from the first sensor.
The signal produced by the PTCa/P(VDF-TrFE) transducer shows that this transducer has been able to detect and distinguish both the extensional and flexural modes of a plate wave
traveling in the 0 [degree] direction.
Prosser, "AE Source Orientation by Plate Wave
Analysis," Journal of Acoustic Emission, 9(4), (1991) 283-288.
Wevers, "One sensor linear location of acoustic emission events using plate wave
theories," Materials Science and Engineering, A265, 254-261, 1999.
Another aspect of plate wave
calibration is the orientation dependence.
The thickness of the vessels and the frequency range of the AE sensors resulted in the consideration of the principal plate wave
modes [S.sub.0] and [A.sub.0].
However, special techniques are required for thin structures due to the dispersive nature of plate wave
Hence, an alternative method for separation of different modes of fracture seems to be the modal analysis of plate waves
. That means the main direction of source movement stimulates a preferred plate wave
In sections on acoustic waves in sonic crystals, elastic waves in phononic crystals, and wave phenomena in phononic crystals, he considers such topics as scalar waves in periodic media, sonic crystals, phononic crystals for surface and plate waves
, coupling acoustic and elastic waves in phononic crystals, evanescent Bloch waves, and spatial and temporal dispersion.