United States of America as Represented by the Administrator of Nasa

Michael R Horne

Joel A Alexa

Joseph N Zalameda

Eric I Madaras

Eric R Burke

Edward H Glaessgen

Stephen W Smith

Robert S Piascik

Peter L Messick

Benjamin T Hailer

Terryl A Wallace

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

A composite material includes a structural material and a shape-memory alloy embedded in the structural material. The shape-memory alloy changes crystallographic phase from austenite to martensite in response to a predefined critical macroscopic average strain of the composite material. In a second embodiment, the composite material includes a plurality of particles of a ferromagnetic shape-memory alloy embedded in the structural material. The ferromagnetic shape-memory alloy changes crystallographic phase from austenite to martensite and changes magnetic phase in response to the predefined critical macroscopic average strain of the composite material. A method of forming a composite material for sensing the predefined critical macroscopic average strain includes providing the shape-memory alloy having an austenite crystallographic phase, changing a size and shape of the shape-memory alloy to thereby form a plurality of particles, and combining the structural material and the particles at a temperature of from about 100-700&#xb0; C. to form the composite material.

Strain-detecting composite materials

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Yorktown, VA, United States of America

Michael R Horne