Determination of nonlinear elastic coefficients in piezoelectric 31-mode transducers using constant current measurements

Abstract A quantitative evaluation method for nonlinear elastic characteristics of piezoelectric materials in high-power operation using constant current (CC) measurements was established. The admittance curves obtained from conventional constant voltage measurements are unsuitable for curve fitting to determine the nonlinear coefficients, due to the hysteresis and jump phenomena in the admittance curve. To overcome this problem, we used CC measurement, where the jump phenomena does not appear. The obtained experimental data with this method was analyzed with the transfer matrix method. The CC approach was demonstrated using a 31-mode potassium sodium niobate ceramic transducer. The obtained nonlinear elastic coefficients were stable above a peak-to-peak current of 0.06 A and converged to the same level as conventional measurement results in the high-amplitude region. This approach offers a robust and reliable framework for material evaluation in high-power piezoelectric drives.