Structural Damage Detection Using an Embedded ETDR Distributed Strain Sensor

Abstract

Feasible application of the Electrical Time Domain Reflectometry (ETDR) distributed strain sensing technique for structural damage detection was investigated in this study. A smallscale concrete beam specimen with an embedded ETDR distributed strain sensor was tested in three-point bending. The resulting ETDR waveforms of the sensor were studied in conjunction with the load-displacement curve of the concrete beam and the video images of the specimen recorded during the test. It was shown that the embedded ETDR sensor was capable of detecting weak points in the structure resulted from structural defects. The embedded sensor also had the capability to detect a load-induced damage at its early stage when no surface crack line was visible. On the occurrence of an apparent crack damage that passed through the sensing line, the embedded sensor could locate its position with a precision within 0.25 . Moreover, the ETDR distributed sensor had the capability to detect multiple cracks simultaneously along a single sensing line.

Strain and Dispersion Dependence of High Frequency Electromagnetic Properties of Carbon Nanotube/Epoxy Nanocomposites

“…TDR technique has been widely used since to detect faults in printed circuit boards and cables [11], geo measurements [12], soil moisture content [12], concrete faults [13,14], liquid flow [15] and delamination crack monitoring [16]. The present research is motivated by the lack of in-situ electromagnetic characterization data of nanocomposites, especially those based on CNTs.…”

Electric Time Domain Reflectometry Sensors for Non-Invasive Structural Health Monitoring of Glass Fiber Composites

“…The technique has been widely used since to detect faults in printed circuit boards and cables [10]. TDR technique has been also used for geological measurements to monitor soil moisture content and rock faults [11] studying faults in concrete structures [12,13], and detection of leakage in pipelines [14]. In composite applications, TDR has been successfully implemented for flow and cure monitoring in liquid composite molding processing [15,16].…”