Development of Acoustic Bandgap Materials and Devices

Acoustic Bandgap (ABG) materials can serve as acoustic filters to reduce and/or modify acoustic signatures. This is made possible by the incorporation of specific internal geometries within ABG panels, that are produced using solid free form fabricationtechniques. Three different types of (ABG) materials are presented, with two selected for further investigation. Two specific applications are presented: the first is in the area of noise suppression for machinery on the Advanced Amphibious AssaultVehicle, and the second is a scheme for flow separation control in jet engines. The work plan presented includes computer analyses, the development of a refined design tool, design, fabrication and testing of various configurations of ABG materials, andthe development of tunable ABG materials. The Phase II effort is geared primarily towards development of ABG materials and devices for the two applications that have been identified.