12 June 2000 High-sensitivity electrical TDR distributed strain sensor
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Electrical time domain reflectometry (ETDR) distributed strain sensing technique has been successfully used in the health monitoring application of civil concrete structures to detect crack damages and in geotechnical application to monitor rock deformation and longwall movement. Although promising results of using commercial ETDR coaxial sensing cables have been shown in recent studies, the low signal-to-noise ratio of the sensors is a research issue needs to be addressed. Since all the commercial coaxial cables are specifically designed for the transmission of electrical signals, the cable configuration is to sustain a virtually constant electrical property under environmental loading effects. For structural strain sensing application, on the other hand, the electrical impedance of the sensor is required to proportionally vary with respect to externally applied loading. Thus, the commercial coaxial cables are indeed not in an optimal configuration for strain sensing application. In this paper, a newly developed high-sensitivity ETDR coaxial strain sensor prototype is presented. The construction of the prototype sensing cable as well as its electrical properties will be described in details. Experimental characterization of the high-sensitivity prototype coaxial sensor was also conducted. Test results of the sensitivity and tension responses of the ETDR signal of the prototype sensor are presented and compared with those of commercial coaxial cables. It is shown that the prototype sensor has a much superior sensitivity and properties for distributed strain sensing application.
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Mark W. Lin, Mark W. Lin, Ayo O. Abatan, Ayo O. Abatan, Yongmei Zhou, Yongmei Zhou, } "High-sensitivity electrical TDR distributed strain sensor", Proc. SPIE 3986, Smart Structures and Materials 2000: Sensory Phenomena and Measurement Instrumentation for Smart Structures and Materials, (12 June 2000); doi: 10.1117/12.388137; https://doi.org/10.1117/12.388137

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