Single Crystal Piezoelectric Actuators for Adaptive Structures

Single crystal piezoelectric actuators are proposed as a means of significantly increasing the stroke of a smart actuator to control the trailing edge flap of a helicopter rotor for vibration control and noise suppression. Conventional piezoelectric ceramic actuators have exhibited inadequate levels of stroke and/or force required to produce an angle of rotation of ±8° at 40 Hz. Single crystals based on (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT) represent a revolutionary advance in piezoelectric actuator technology. These materials exhibit 5 to 10 times the strain of conventional ceramic piezoelectrics with equivalent deliverable force. Therefore, they offer a much broader design space for adaptive systems than is currently available with ceramic actuators, active fiber composites, electric motors or magnetic devices. The objectives of this project are: 1) to fabricate complete actuators of three leading actuator types using new single crystal piezoceramic material technology. Specifically, a d33 stack, and d32 bender, and a d15 induced shear tube will be addressed, 2) to measure and characterize piezo-coupling coefficients under electromechanical conditions representative of smart rotor and airframe applications, 3) to conduct a performance analysis quantifying the projected gains in actuation capability given the measured single crystal element characteristics.