Nonlinear measurements of piezocomposite transducers with burst excitation

摘要

Resonant transducers made with composites and excited by burst signals are used in high power applications, where the spatial resolution is important, such as non-destructive testing (NDT) or medical applications. The characterization of nonlinear resonant behavior must be carried out in similar conditions as in the device application: the same pulsed signal and excitation level. A new measurement method is presented, without the use of typical network or impedance analyzer that carries out measurements with steady state signals. The measurement of the transient response of the current flowing in the piezocomposite transducer after the end of a burst signal excitation allows us to measure the mechanical loss tangent tan /spl delta//sub m/ and shift frequency, versus the amplitude level. This method enables us to measure this nonlinear behavior without overheating the transducers; it also extends the level amplitudes of the previous nonlinear behavior methods.