A uniformizing method for the free vibration analysis of metal-piezoceramic composite thin plates

A uniformizing method is presented for the free vibration analysis of metal-piezoceramic composite thin plates which are popular structures of thin plate-type ultrasonic motors. A metal-piezoceramic composite thin plate is normally composed of a metal plate with one surface adhering to a piezoelectric ceramic plate. The uniformizing method described in this paper aims to obtain an equivalent single-layer uniform thin plate which has the same free vibration characteristics as the metal-piezoceramic composite thin plate. Hence the free vibration analysis for a metal-piezoelectric composite thin plate can be performed through investigating the free vibration behaviors of the equivalent single-layer uniform thin plate by using classical thin plate theory. In order to confirm the validity of the uniformizing method in this paper, two actual configurations of the metal-piezoceramic composite thin plate structure are constructed. By comparing the measured natural frequencies and vibration models with those yielded by the uniformizing method, one finds not only excellent agreement but also satisfying precision for engineering uses.