5aea3. Simulation of Linear Aeracoustic Propagation in Lined Ducts with Discontinuous Galerkin Method. 5aea4. Engineering Acoustic Lenses with Help from Evolution. 5aea6. Dissipative Silencers with an Extended Inletõoutlet and Baffles

Recent work has demonstrated piezoelectric behavior in voided polymers. It is thought that the piezoelectricity results from the creation of space charges bordering the voids when the material is exposed to an electric field in excess of the breakdown strength. The resulting voided piezoelectric material is more flexible than conventional piezoelectric ceramics, and may be far less expensive to manufacture. Accurate models of piezoelectricity in voided materials are needed to explore the limits of performance and their use under a wide range of conditions. We are using finite element analysis to develop a model of the mechanical, electrical, and piezoelectric behavior in voided materials. Results for some of the materials of current interest, such as low-density polypropylene LDPP and porous polytetrafluoroethylene PTFE will be presented. Work performed under a JHU/APL sabbatical to the JHU/WSE.