STEADY-STATE RESPONSE OF ACOUSTIC CAVITIES BOUNDED BY PIEZOELECTRIC COMPOSITE SHELL STRUCTURES

A formulation to calculate the coupled response of composite shells wi th embedded piezoelectric layers and an enclosed acoustic fluid is pre sented in this paper. The methodology consists of three parts: (1) a f ormulation for the electro-mechanical response of piezoelectric shells ; (2) a formulation for the three-dimensional acoustic response of the enclosed fluid; and (3) the combination of the formulations (1) and ( 2) to calculate the coupled smart structure-acoustic fluid response. A recently developed mixed field laminate theory is adapted for the ana lysis of piezoelectric shells. The theory combines the first order she ar theory kinematic assumptions with a layer-wise approximation for th e electric potential. Shell geometry is described in an orthogonal cur vilinear co-ordinate system and general piezoelectric material descrip tions and laminate configurations are considered. A boundary element f ormulation is developed to calculate the acoustic response of the encl osed fluid. Quadratic conforming boundary elements are used to discret ize the fluid boundary. Advanced numerical integration techniques are employed to calculate singular elements in boundary element matrices. The treatment of distributed acoustic sources is also presented. A for mulation to calculate the coupled fluid-structure response is also dev eloped. Relations between the structural and acoustic variables on the structure-fluid interface are utilized to generate the coupled system of equations in terms of the kinematic shell variables and acoustic p ressures on the fluid boundary. The convergence of the present develop ments is established by studying a circular cylindrical shell with an attached piezoelectric layer. The coupled response is investigated for various types of mechanical loads and active voltage patterns. (C) 19 97 Academic Press Limited.