Measurement of stress/charge coefficients of a thin polyvinylidene fluoride film

Abstract

A new experimental/analytical approach is used to measure a piezoelectric coefficient of polyvinylidene fluoride (PVDF). This method is based on the volume displacement of a vibrating beam. The obtained value of the stress/charge coefficient is checked using modal coordinate measurement theory and finite element analysis. A PVDF film is cut into two sensors shape. These sensors measure, respectively, the volume displacement and modal coordinate of a simply supported beam vibrating at its first mode. An accelerometer and a force gauge are used to measure the volume displacement and the modal coordinate of the beam. Then, PVDF volume displacement sensor equation developed by Guigou et al. is used with the experimental data to find the stress/charge coefficient e31. This value of e31 is first checked using the PVDF modal sensor equation from Lee and Moon. Then, the anys finite element code is used to validate the method. Experimental value of e31 obtained at room temperature is presented and compared with existing data. Excellent agreement is found. The extension of the method to 2D structure to determine the value of e31 and e32 simultaneously is introduced.