Combination of analytical and finite element methods to obtain acoustic fields in complex structures driven by piezoelectric multi-layered transducers

This paper presents a method to obtain the acoustic field in complex structures driven at a plane by a multi-layered piezoelectric transducer of simple geometry. The Finite Element Method (FEM) is used in the complex structure to compute the fields and the acoustic impedance presented to the transducer. This procedure is computer intensive, but is obtained only once for a frequency range. The electric impedance of the transducer loaded with the computed acoustic impedance is obtained with the chain matrix, a fast analytical method, and FEM. These two approaches were applied to a steel tube driven through a coupler by a power transducer. Measured and calculated electric impedances are compared.