Design of single-crystal vibration absorbers

The development of a new class of devices for the suppression of structural vibration becomes possible by exploiting the unique properties of single crystal piezoceramics. These vibration absorbers will be compact, robust, and demand minimal power for operation. They will be characterized by frequency agility, which means that the absorber tuning parameters can adapt rapidly to controller command and tuning can be accomplished over a wide frequency range. Identified applications include control of turbomachinery vibration, flexible space structures, jitter control in optical systems, and vibration isolation in machinery mounts. The current state of the art adaptive vibration absorber tuning range is fundamentally limited by the electromechanical coupling of presently available polycrystalline piezoceramic materials. The narrow tuning range characteristic of current vibration absorbers severely limits the implementation of the solid-state absorber concept. This work presents efforts related to the design of vibration absorbers that use the single-crystal piezoceramic large electromechanical coupling to achieve greatly enhanced tuning over a wide frequency range. Absorber electromechanical coupling-coefficients greater than 50% were obtained. Design issues specifically related to the use of single crystals in vibration absorbers were identified and addressed. Several device configurations were analyzed and tested. Good agreement was observed between analytical and experimental results.