Piezo-tubes

The piezoelectrical properties of a bi-polar electret-tube subjected to a side stress are considered. A model for the non-uniform structure, containing “soft” and “hard” dielectric layers with charges stored at the interfaces was applied to determine the value of the piezoelectric coefficient d33. The d33 measured under static conditions on PTFE tubes submitted to partial discharge charging in an electric dc field was found to be 40±10 pC/N. Similar results were obtained for a “fabric” made from the PTFE tubes. The time stability of the piezoelectric coefficient d33 was also examined and the technical utility of the prepared structures was confirmed.