Automatic determination of complex constants of piezoelectric lossy materials in the radial mode

An iterative automatic method is described for the characterization of lossy piezoelectric materials in the radial resonance mode based on the use of the more general expression for the complex admittance. From the experimental data of Y at four adequately selected frequencies, the constants of the material are determined with the necessary accuracy to reproduce the piezoelectric behaviour of the sample around resonance. The IEEE-176 Standard procedure has been automatized for the initial estimation of the real parts of the elastic constants. The method is applicable even to those materials in which said standard does not allow one to determine the piezoelectric constants.