Evaluation of the property coefficients of piezoelectric polymers

Abstract

Analytical models are presented for evaluating the property coefficients of thick-film piezoelectric polymers. In particular, these models facilitate the evaluation of the complex elastic compliance coefficients ŝ1′1′D, ŝ12D, ŝ22D, ŝ33D, and ŝ66D from the measured set of quantities {fm,fl,fn,Al,An}, where fm is the resonance frequency of the test specimen fl<fm<fn and Al and An are the relative amplitudes at the selected frequencies fl and fn. Impact excitation of the test samples, a vibration sensor, and a FFT-based spectrum analyzer are used to measure these quantities. In addition, a model is presented for evaluating the complex electromechanical coupling factor k̂31 from the measured value of the transfer function of the length expander polymer bar with divided electrodes. Experimental results were obtained on PVF2 samples made by Raytheon Research Division, and the analytical models were used to evaluate the property coefficients of these samples. The results of these evaluations for ŝ11D, ŝ1′1′D, ŝ12D, ŝ22D, ŝ33D, ŝ66D, and k̂31 are presented.