Abstract
The near-field acoustic levitation is levitate a planer object having relatively large size and weight on a plate vibrating in ultrasonic frequency with 10-100μm air gap. This phenomenon has been studied as a non-contact transportation technology for a fragile thin plate such as flat panel display glass substrate. In this study, we concern non-contact excitation of a planer object by using near-field acoustic levitation and investigate the applicability of this phenomenon as a non-contact excitation of planer objects. In this paper, we realized a non-contact excitation method to vibrate the levitated object at arbitrary low frequency by exciting the vibration plate with high and low frequency sine wave. The experimental study of non-contact excitation of glass plate specimens near the natural frequencies has shown a remarkable difference in the modulation intensity of the displacement responses of the intact and cracked specimens, which may indicates an existence of the crack in the levitated plate.
