Hybrid composite materials using shape memory alloy actuators to provide vibration and acoustic control

Shape memory alloys exhibit several characteristics which make these materials particularly attractive for modal modification of structures: a large change in modulus upon heating through the phase transformation temperature, an exceptionally high specific damping capacity, and an ability to generate large forces through the shape recovery mechanism. Used as either embedded members in a composite structure, or as an external actuator when caused to undergo the shape transformation by heating, these actuators can provide a significant change in acoustic response of the structure. The paper describes shape memory alloy characterization and the design of an actuator system for modifying the acoustic response of a clamped plate.