Three-dimensional free vibration analysis of a fluid-filled piezoceramic hollow sphere

This article presents an exact three-dimensional analysis of the free vibra tion of a piezoceramic hollow sphere filled with a compressible fluid mediu m. Three displacement functions are introduced to rewrite three components of the mechanical displacement in spherical coordinates. For the problem of general nonaxisymmetric free vibration, it is shown that the controlling e quations are finally simplified to an uncoupled second-order ordinary diffe rential equation and a coupled system of three such equations. Solutions to these differential equations are obtained. The coupled vibration problem o f piezoceramic hollow sphere is then considered. It is found that there are two independent classes of vibrations. The first class is independent of t he contained fluid and is not affected by the electric field, while the sec ond is related to both the fluid parameter acid the electric field. Exact f requency equations are derived and numerical results are finally presented. (C) 2001 Elsevier Science Ltd. All rights reserved.