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Active Piezoelectric Vibration Control of Subscale Composite Fan BladesAs part of the Fundamental Aeronautics program, researchers at NASA Glenn Research Center (GRC) are investigating new technologies supporting the development of lighter, quieter, and more efficient fans for turbomachinery applications. High performance fan blades designed to achieve such goals will be subjected to higher levels of aerodynamic excitations which could lead to more serious and complex vibration problems. Piezoelectric materials have been proposed as a means of decreasing engine blade vibration either through a passive damping scheme, or as part of an active vibration control system. For polymer matrix fiber composite blades, the piezoelectric elements could be embedded within the blade material, protecting the brittle piezoceramic material from the airflow and from debris. To investigate this idea, spin testing was performed on two General Electric Aviation (GE) subscale composite fan blades in the NASA GRC Dynamic Spin Rig Facility. The first bending mode (1B) was targeted for vibration control. Because these subscale blades are very thin, the piezoelectric material was surface-mounted on the blades. Three thin piezoelectric patches were applied to each blade two actuator patches and one small sensor patch. These flexible macro-fiber-composite patches were placed in a location of high resonant strain for the 1B mode. The blades were tested up to 5000 rpm, with patches used as sensors, as excitation for the blade, and as part of open- and closed-loop vibration control. Results show that with a single actuator patch, active vibration control causes the damping ratio to increase from a baseline of 0.3% critical damping to about 1.0% damping at 0 RPM. As the rotor speed approaches 5000 RPM, the actively controlled blade damping ratio decreases to about 0.5% damping. This occurs primarily because of centrifugal blade stiffening, and can be observed by the decrease in the generalized electromechanical coupling with rotor speed.
Document ID
20120012831
Document Type
Conference Paper
Authors
Duffy, Kirsten P. (Toledo Univ. Cleveland, OH, United States)
Choi, Benjamin B. (NASA Glenn Research Center Cleveland, OH, United States)
Provenza, Andrew J. (NASA Glenn Research Center Cleveland, OH, United States)
Min, James B. (NASA Glenn Research Center Cleveland, OH, United States)
Kray, Nicholas (General Electric Co. Cincinnati, OH, United States)
Date Acquired
August 26, 2013
Publication Date
June 11, 2012
Subject Category
Composite Materials
Report/Patent Number
E-18244
GT 2012-68639
Meeting Information
ASME Turbo Expo 2012: Power for Land, Sea and Air (GT2012)(Copenhagen)
Funding Number(s)
WBS: WBS 561581.02.08.03.15.13
CONTRACT_GRANT: SAA3-260
Distribution Limits
Public
Copyright
Other