Reduced-parameter ultrasound electrical impedance spectroscopy for characterization of piezoelectric transducers and polymer materials.

This work presents a reduced-parameter ultrasound electrical impedance spectroscopy (RP-UEIS) framework for estimating the complex electromechanical parameters of piezoelectric transducers - specifically lead zirconate titanate (PZT) ceramics - and the viscoelastic properties of polymer materials. The method combines a low-cost electrical impedance spectroscopy setup with an inverse finite-element fitting procedure to identify material parameters from measured impedance spectra. A sensitivity-based parameter analysis of the transducer reduces the dimensionality of the inverse problem from sixteen to ten parameters, significantly improving computational efficiency. Once the transducer parameters are calibrated, the viscoelastic properties of polymer samples can be identified in approximately one hour, compared with the ∼10 hours typically required by the original UEIS method. Using a PZT-4 reference transducer, complex elastic moduli and acoustic attenuation parameters are estimated at 1MHz for several polymeric materials commonly used in additive and subtractive manufacturing. The RP-UEIS framework is further demonstrated through the design of an acoustofluidic chip, where the identified polylactic acid (PLA) parameters are incorporated into a finite-element model of a circular half-wavelength resonator. RP-UEIS provides a practical and efficient tool for the characterization of polymer materials and for physically consistent parameter estimation in the modeling of polymer-based acoustofluidic devices.