Visualization of ultrasonic vibrations in piezoelectric ceramics using telethermography

With the help of the recent infrared (IR) telethermography apparatus, a portion of the temperature scale may be transposed to the color scale to form colored thermal pictures of an object. By covering piezoelectric ceramics with a thin film of acoustic black body, the vibrational states for well-characterized modes, in tubes and disks, have been quasi-instantaneously visualized. Localized heating in the surface film reflects the state of vibratory deformation of the underlying substrate. The telethermographs provided agree well with calculated frequencies and with measurements taken, point by point, with the held of a vibration sensor. We may thus verify that the hot points correspond to vibration nodes and to constraint antinodes. The colored pictures were taken from a telethermographic device AGA 680 M.