Contribution
Estimation of piezoelectric material parameters under varying electric field conditions
* Presenting author
Abstract:
Piezoelectric ceramics are used in high-power ultrasonic sensors and actuators, where they are subjected to considerable electrical and mechanical loads, resulting in nonlinear effects. One method for analysing the nonlinear behaviour of such materials is to shift the operating points. The application of a DC bias voltage during electrical impedance measurements results in a shift in the electrical operating point, thereby enabling the characterisation of the material's linear behaviour at the points to estimate its nonlinear properties.This study presents a measurement setup for the purpose of measuring the electrical impedance of piezoelectric ceramics under varying electrical bias voltages. Measurements are conducted with electric field strengths up to ±500 V/mm, which is representative of conditions that may be encountered in a real-world application. For samples of ring-shaped piezoceramic material with a thickness of 1 mm, the requisite direct current (DC) voltages are in the range of ±500 V. A purpose-built circuit superimposes these DC voltages on the measurement voltage. The resulting impedance measurements at each operating point are used to estimate the material parameters as a function of the applied electric field by solving an inverse problem, matching the measured electrical impedance with the output of a simulation model.