FREQUENCY- AND FIELD-DEPENDENT NON-LINEARITIES OF THE SHEAR STRAIN PIEZOELECTRIC COUPLING COEFFICIENT (D15) OF A POLED SOFT PIEZOCERAMIC MATERIAL (PZT PIC255)
Résumé
This contribution investigates the non-resonant driving frequency- and AC electric field-dependent operational non-linearities of the thickness-shear strain piezoelectric coupling
coefficient (d15) of poled soft piezoceramic (PZT PIC255) rectangular patches. Therefore, first, an experimental database is analyzed for varying driving frequency (10Hz-1kHz) under fixed input voltages in order to find a threshold frequency from which there is no frequencydependence and, for varying input voltages (20V-400V) under a fixed driving frequency, a threshold voltage from which there is no field-dependence is searched. Then, the Levenberg-Marquardt-Fletcher algorithm is adapted and implemented in order to optimize two-parameter additive and multiplicative power laws for modelling the field-dependent non-linearity of soft piezoceramics. It is found that, while the additive power law is slower than the multiplicative one, they perform similarly for wide ranges of driving frequency (200Hz-1kHz) and actuation voltage (100V-400V). Besides, their two parameters are found frequency-dependent.