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

United States of America as Represented by the Administrator of Nasa

Other

Eric I Madaras

Joseph N Zalameda

Eric R Burke

Michael R Horne

Robert F Anastasi

A system for monitoring damage progression in a composite structure includes a load sensor, acoustic emission sensors, a camera, and a monitoring device. The load sensor measures an applied load to the structure. The sensors measure acoustic emission data indicative of possible damage to the structure. The camera captures image data of the structure in a designated portion of the electromagnetic spectrum. The monitoring device executes a method by which the acoustic emission data is synchronously collected with the image data and the applied load. The device automatically maps the acoustic emission data onto the image data to detect an area of damage progression in the composite structure. A failure event in the detected area of damage progression may be predicted using the mapped data, and a control action may be executed in response to the predicted failure event.

System and method for progressive damage monitoring and failure event prediction in a composite structure

The present invention uses the generation and detection of acoustic guided waves to evaluate the condition of the insulation on electrical wiring. Low order axisymmetric and flexural acoustic modes are generated in the insulated wire and travel partially in the center conductor and partially in the outer insulation. The stiffness of the insulation and the insulation's condition affect the overall wave speed and amplitude of the guided wave. Analysis of the received signal provides information about the age or useful life of the wire insulation. In accordance with the present invention, signal transmission occurs at one location on the electrical wire to be evaluated, and detection occurs at one or more locations along the electrical wire. Additional receivers can be used to improve measurement accuracy. Either the transmission transducer or one or more receiver transducers may be angled at other than 90 degrees to the wire. Generation of the guided waves can be accomplished by imparting a pressure pulse on the wire. Alternative embodiments include generation via a laser, such as a Q-switched laser or a laser diode.

Non-destructive evaluation of wire insulation and coatings

A method for ultrasonic imaging of interior structures and flaws in a test specimen with a smooth or irregular contact surfaces, in which an ultrasonic transducer is coupled acoustically to the contact surface via a plurality of ultrasonic wave guides with equal delay times. The wave guides are thin and bendable, so they adapt to variations in the distance between the transducer and different parts of the contact surface by bending more or less. All parts of the irregular contact surface accordingly receive sound waves that are in phase, even when the contact surface is irregular, so a coherent sound wave is infused in the test specimen. The wave guides can be arranged in the form of an ultrasonic brush, with a flat head for coupling to a flat transducer, and free bristles that can be pressed against the test specimen. By bevelling the bristle ends at a suitable angle, shear mode waves can be infused into the test specimen from a longitudinal mode transducer.

Method for ultrasonic imaging and device for performing the method

A method for the x-ray inspection of materials making use of the Moire effect is described. The Moire effect results when two patterns are superimposed, a third pattern is produced. Any change in either of the first two patterns creates a change in the third. Moire inspection is common with visible light, this invention allows the technique to be extended to locations inaccessible to visual inspection. A first pattern of high radio contrast material is attached to or included in the sample. X-rays are projected through the sample. A second pattern is imposed at the observation point, either before or after the formation of the x-ray image. The two patterns interact to create a third, Moire, pattern. As the material is stressed the Moire pattern changes, the degree of change indicating the degree of stress.

Radiographic moire

A method and apparatus are provided for indicating disbonds in joint regions. A critical bondline region is located between a first material and a second material having a higher acoustic impedance than the first material. A form member having an acoustic impedance which is substantially similar to the first material has a first face which is form fitted to a surface of the first material opposite to and non-parallel with the critical bondline region. The form member has an opposite second face which is shaped to be parallel to the critcal bondline region. Transducers are acoustically coupled to the second face of the form member to generate an ultrasonic tone burst through the acoustically similar form member and first material which is reflected by the critical bondline region. This reflected tone burst is received and a resulting signal is compared with a normal signal for no disbond to determine the presence of an unacceptable disbond.

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Yorktown, VA, United States of America

Eric I Madaras