Piezo Polymer Films for Enhanced Acoustic Transmission Loss and Absorption

The subject of this paper deals with the construction, characterization, modeling, and control of sensors and actuators made from piezoelectric polymers. The objective of this control was to improve the transmission loss and absorption characteristics of passive noise control materials by the addition of actively controlled component and to do so without a prohibitive cost. A brief background of piezoelectric materials and the practical considerations when using them is presented. The construction of piezo sensors and actuators from PVdF film is described, as is the development of cost effective driver, amplifier, and filter electronics for the system. In addition, the construction of an impedance tube testing apparatus is described. Then, the system is identified and control design models constructed. Next, the resonant controller structure utilized in preliminary experiments is presented. Finally, the experimental setup, investigation, and results of these actively controlled piezo samples are presented. Preliminary results show that collections of these resonant controllers are able to lead to significant (greater than 10dB on 30–50Hz bands) reductions. This would be a very effective method for tonal noise mitigation below 1500 Hz. Also presented are future improvements of the material sensing and new directions of research that are now in the experimental phase.