New methods to characterize radially polarized piezoelectric ceramic cylindrical shells of finite length

New methods to experimentally determine the electroelastic coefficients of radially polarized piezoelectric ceramic cylindrical shells (RPPCCSs) of arbitrary length to radius ratio are presented. The real parts of epsilon(33)(T), S-11(E), S-12(E), and g(31) are explicitly expressed in terms of quantities which can be easily measured. The quantities can be obtained from the measured frequency-dependent input electrical admittances (IEAs) of RPPCCSs with free ends. The theoretical IEA based on the two-dimensional equations of state and the membrane approximation is used to derive the explicit expressions. Some methods cannot be used when the resonance frequencies, which are required as inputs, cannot be identified. This occurs when there are several resonances in a narrow frequency band or losses are high. However, the other methods can be used. The methods are validated by using simulated data. The required input data are computed using the theoretical expression for the IEA and an assumed set of complex electroelastic coefficients. It is then shown that the real parts of the coefficients of RPPCCSs with a small or large length to radius ratio and low or high mechanical losses can be accurately determined by using the input data. The effect of measurement errors on the overall accuracy of the experimentally determined values is also discussed. The methods are further validated by the good agreement over a wide frequency range between measured IEAs and the IEAs computed using the experimentally determined values of coefficients. (C) 1997 Acoustical Society of America.