Measurement of Stress/Charge Coefficients of a Thin Polyvinylidene Fluoride Film

An experimental/analytical approach is used to detemine the piezoelectric coefficients of PolyVinyliDene Fluoride (PDVF). PVDF manufacturers usually publish the values of the charge coefficients in the 1 or 3 directions of the piezoelectric film. However; some applications, such as the use of volume displacement sensors for vibrating plates in active noise control, require the knowledge of the PVDF charge coefficients in the 2 direction. The objective of this work is to determine experimentally and numerically the stress/charge coefficient of a PVDF film in the 2 direction. The method is based on volume displacement measurement of a vibrating beam. Two PVDF volume displacement sensors are fabricated with two different piezoelectric 1 and 2 directions respectively. An accelerometer is used to measure the volume displacement of the vibrating beam. The values are compared with the output charge of the PVDF sensors to determine the unknown stress/charge coefficient. Results obtained at room temperature are presented and compare favorably with existing similar data.Copyright © 2004 by ASME