The differing vibration modes
provide the following characteristics:
- Flextural vibration
Vibration in bending directions.
- Length vibration
Length vibration that expands or contracts a thin plate.
- Area expansion vibration
Area expansion vibration over a surface of a thin plate or disk.
- Thickness shear vibration
Thickness shear vibration over a surface of a thin plate (when the
electric field is perpendicular to the direction of polarization).
- Thickness expansion vibration
Vibration in the thickness direction of a thin plate.
- Surface acoustic wave (Rayleigh wave)
Elastic wave that conveys energy over the board surface and
exponentially reduces energy in the board thickness direction.
- BGS wave
In principle, the energy conveying behavior is the same as above. The
most significant difference between surface acoustic waves and BGS
waves is that surface waves convey energy with both longitudinal and
transverse waves, while BGS waves convey energy only with transverse
waves.
" BGS wave" was named after the initial letters of Bleustein, Gulyaev
and Shimizu who discovered this wave at around the same time (around
1968).
|
