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Measurement of large strains in ropes using plastic optical fibers

United States Patent

February 14, 2006
View the Complete Patent at the US Patent & Trademark Office
Oak Ridge National Laboratory - Visit the Partnerships Directorate Website
A method for the direct measurement of large strains in ropes in situ using a plastic optical fiber, for example, perfluorocarbon or polymethyl methacrylate and Optical Time-Domain Reflectometer or other light time-of-flight measurement instrumentation. Protective sheaths and guides are incorporated to protect the plastic optical fiber. In one embodiment, a small rope is braided around the plastic optical fiber to impose lateral compressive forces to restrain the plastic optical fiber from slipping and thus experience the same strain as the rope. Methods are described for making reflective interfaces along the length of the plastic optical fiber and to provide the capability to measure strain within discrete segments of the rope. Interpretation of the data allows one to calculate the accumulated strain at any point in time and to determine if the rope has experienced local damage.
Williams; Jerry Gene (The Woodlands, TX), Smith; David Barton (Oak Ridge, TN), Muhs; Jeffrey David (Lenoir City, TN)
10/ 430,058
May 5, 2003
This invention was made with Government support under Contract No. DE-AC05-000R22725 awarded by the United States Department of Energy. The Government has certain rights in this invention.