Semi-active vibration control with piezoelectric materials as variable-stiffness actuators

1999 ◽  
Author(s):  
William W. Clark
Keyword(s):  
Vibration Control ◽  
Piezoelectric Materials ◽  
Active Vibration Control ◽  
Variable Stiffness ◽  
Active Vibration ◽  
Variable Stiffness Actuators

scholarly journals Active Piezoelectric Vibration Control of Subscale Composite Fan Blades

2012 ◽  
Author(s):  
Kirsten P. Duffy ◽  
Benjamin B. Choi ◽  
Andrew J. Provenza ◽  
James B. Min ◽  
Nicholas Kray
Keyword(s):  
Vibration Control ◽  
Electromechanical Coupling ◽  
New Technologies ◽  
Piezoelectric Materials ◽  
Fiber Composite ◽  
Damping Ratio ◽  
Active Vibration Control ◽  
Rotor Speed ◽  
Blade Vibration ◽  
Active Vibration

As 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.

Quarter-Cycle Switching Control for Switch-Shunted Dampers

2004 ◽  
Vol 126 (2) ◽  
pp. 278-283 ◽  
Author(s):  
Gregg D. Larson ◽  
Kenneth A. Cunefare
Keyword(s):  
Vibration Control ◽  
Piezoelectric Materials ◽  
Active Vibration Control ◽  
Switching Control ◽  
Single Frequency ◽  
Effective Bandwidth ◽  
Control Logic ◽  
Resonant States ◽  
Active Vibration ◽  
Specific Implementation

Significant interest has been generated by the possibilities of active vibration control through the implementation of state switching, with a specific implementation embodied through piezoceramic shunting. A state-switched absorber (SSA) is a vibration absorber that has the unique ability to change its resonant state amongst multiple distinct resonant states while in motion, thereby increasing the effective bandwidth over that of a single frequency device and thereby allowing control of multi-frequency, transient, and time-varying disturbances. In contrast, a switch-shunted damper (SSD) is a variant of an SSA that is used to increase the damping of the structure to which the damper is applied. Active vibration control applications discussed in the literature indicate the potential advantages of SSDs which employ piezoelectric ceramics as switchable springs with control algorithms that require switching states at points of non-zero strain. However, consideration of the constitutive equations for piezoelectric materials indicates a discontinuity in the electrical and mechanical conditions imposed by switching the stiffness at non-zero strains. A prototype SSD has been built and tested to experimentally investigate switching control logic and electrical and mechanical discontinuities at switching points; experimental measurements with this prototype SSD indicate that quarter-cycle switching algorithms which include switching states at a condition of maximum strain yield enhanced damping effectiveness but also leads to the generation of potentially undesirable mechanical transients.

scholarly journals Active Piezoelectric Vibration Control of Subscale Composite Fan Blades

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Kirsten P. Duffy ◽  
Benjamin B. Choi ◽  
Andrew J. Provenza ◽  
James B. Min ◽  
Nicholas Kray
Keyword(s):  
Vibration Control ◽  
Electromechanical Coupling ◽  
New Technologies ◽  
Piezoelectric Materials ◽  
Fiber Composite ◽  
Damping Ratio ◽  
Active Vibration Control ◽  
Rotor Speed ◽  
Blade Vibration ◽  
Active Vibration

As 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.

Sign in / Sign up

Export Citation Format

Share Document