Thin rod flexural acoustic wave sensors

摘要

A flexural acoustic wave sensing method and efficient, simple, miniature and economical ultrasonic devices using thin rods are presented. The diameter of the thin rod is less than one acoustic wavelength. The lowest order flexural acoustic wave, F.sub.11 mode, propagating along such thin rods is used. The thin rod materials can be metals, glasses, ceramics, polymers and single crystals. Any external disturbance which can alter the propagation characteristics of F.sub.11 mode may be monitored by recording such variation. Fiber acoustic interferometers, which are built by jointing two thin rods, can offer high sensitivity. These devices are primarily used for sensors.