The United States of America As Represented by the Administrator of the

United States of America As Represented by the Administrator of Nasa

Richard J Silcox

Roberto J Cano

Travis L Turner

Randolph H Cabell

Christopher M Cagle

Ralph D Buehrle

George C Hilton

Gary P Gibbs

Chris R Fuller

A jet engine exhaust nozzle flow effector is a chevron formed with a radius of curvature with surfaces of the flow effector being defined and opposing one another. At least one shape memory alloy (SMA) member is embedded in the chevron closer to one of the chevron's opposing surfaces and substantially spanning from at least a portion of the chevron's root to the chevron's tip.

Jet engine exhaust nozzle flow effector

Arrays of actuators are affixed to structural elements to impede the transmission of vibrational energy. A single pair is used to provide control of bending and extensional waves and two pairs are used to control torsional motion in addition to these two types of wave motion. The arrays are applied to a wide variety of structural elements such as a beam structure that is part of larger framework that may or may not support a rigid or non-rigid skin. Electrical excitation is applied to the actuators that generate forces on the structure. These electrical inputs may be adjusted in their amplitude and phase by a controller in communication with appropriate vibrational wave sensors to impede the flow of vibrational power in all of the above mentioned wave forms beyond the actuator location. Additional sensor elements can be used to monitor the performance and adjust the electrical inputs to maximize the attenuation of vibrational energy.

Method and apparatus for minimizing multiple degree of freedom vibration

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Poquoson, VA, United States of America

Richard J Silcox