Development of an electrical time domain reflectometry (ETDR) distributed strain sensor

Lin, Mark W.; Thaduri, Jagan; Abatan, Ayo O.

doi:10.1088/0957-0233/16/7/012

Cited by 35 publications

(33 citation statements)

References 10 publications

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“…In TDR, the incident wave is transmitted and reflected at locations where the characteristic impedance varies. When the characteristic impedance changes from Z a to Z b because of the presence of a crack, the reflected wave V r becomes [18] …”

Section: Damage Detection Using 2-d Msl and Tdrmentioning

confidence: 99%

Uncertainty Visualization of Estimated Damage Using Kriging Model: Application to Time-Domain Reflectometry Sensing

2015

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We used a Kriging model to visualize the uncertainty of the estimated damage location from time domain reflectometry (TDR) measurements. The damage can be clearly detected on the transmission line through the application of a 2D microstrip line differential circuit for TDR. The reflection voltages between the observed points are interpolated, and the uncertainty is obtained by Kriging. We integrated the estimation and uncertainty contour maps into a single figure for easier understanding and statistical quantification. We used the measured TDR data to investigate three types of visualization models for damage inspection: hue-saturation-intensity color, crack existence probability, and expected improvement. All three methods quantitatively visualize the estimated crack configuration with uncertainty in a single figure. By operating these visualization models depending on the inspector's preferences, more appropriate crack estimation can be performed for wide-area fast scantype inspections such as TDR. In particular, the latter two models can be directly used as an evaluation index for secondary inspection.

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Section: Damage Detection Using 2-d Msl and Tdrmentioning

confidence: 99%

Uncertainty Visualization of Estimated Damage Using Kriging Model: Application to Time-Domain Reflectometry Sensing

2015

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“…From a practical point of view, such a parallel aluminum plate is not always required. Equation (2) shows that smaller W gives smaller spacing h in the transmission line. For example, the small-width-copper-mesh strip typically used for anti-lightning systems would be an appropriate material to construct the transmission lines.…”

Section: Impedance Matchingmentioning

confidence: 99%

“…Chen et al used a TDR method to detect cracks in concrete structures by embedding a coaxial cable in the concrete (1) . Lin et al proposed a new method to measure applied strain using TDR with a coaxial cable (2) . Okuhara et al have applied TDR to detect damage in glass composites using a carbon fiber bundle as a sensor (3) .…”

Section: Introductionmentioning

confidence: 99%

Damage Monitoring of CFRP Plate Using Self-Sensing TDR Method

Kurokawa

Todoroki²,

Mizutani³

2012

JMMP

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Laminated CFRP structures are applied to many aerospace structures. Although CFRP laminates have high specific strength and specific stiffness, an impact load easily creates damage such as delamination cracking, matrix cracking, and fiber breakage. Damage to laminated CFRP is usually difficult to detect by visual inspection. As a result, damage monitoring systems are required for large laminated CFRP structures. Many researchers have already proposed self-sensing monitoring systems which measure electrical resistance changes in the laminated CFRP. This method, however, requires a lot of electrodes. In the present study, a new time domain reflectometry (TDR) method using an electrical pulse signal and reinforcement carbon fiber sensors is adopted as a monitoring method. The method is applied to a 2-m long CFRP strip plate specimen to detect an ideal damage mechanical notch using a reflected pulse signal. In addition, the effect of the orthotropic conductance of the CFRP plate is experimentally investigated using multiple electrodes, and is shown to be negligible.

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“…The high quality of the recorded signal of the TDR100 (Campbell Scientific Inc), which has a time to peak of roughly 200 ps, allows inversion at a spatial resolution of 0.01 m (Oswald et al, 2003;Lin et al, 2005). The solution of Eq.…”

Section: Stdr Signal Inversionmentioning

confidence: 99%

A quality assessment of Spatial TDR soil moisture measurements in homogenous and heterogeneous media with laboratory experiments

Graeff

Zehe²,

Schlaeger³

et al. 2010

Hydrol. Earth Syst. Sci.

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Abstract. Investigation of transient soil moisture profiles yields valuable information of near-surface processes. A recently developed reconstruction algorithm based on the telegraph equation allows the inverse estimation of soil moisture profiles along coated, three rod TDR probes. Laboratory experiments were carried out to prove the results of the inversion and to understand the influence of probe rod deformation and solid objects close to the probe in heterogeneous media. Differences in rod geometry can lead to serious misinterpretations in the soil moisture profile, but have small influence on the average soil moisture along the probe. Solids in the integration volume have almost no effect on average soil moisture, but result in locally slightly decreased moisture values. Inverted profiles obtained in a loamy soil with a clay content of about 16% were in good agreement with independent measurements.

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Development of an electrical time domain reflectometry (ETDR) distributed strain sensor

Cited by 35 publications

References 10 publications

Uncertainty Visualization of Estimated Damage Using Kriging Model: Application to Time-Domain Reflectometry Sensing

Uncertainty Visualization of Estimated Damage Using Kriging Model: Application to Time-Domain Reflectometry Sensing

Damage Monitoring of CFRP Plate Using Self-Sensing TDR Method

A quality assessment of Spatial TDR soil moisture measurements in homogenous and heterogeneous media with laboratory experiments

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