Effects of Concrete on Propagation Characteristics of Guided Wave in Steel Bar Embedded in Concrete

Zheng, Zhuo; Lei, Ying

doi:10.1155/2014/910750

Cited by 7 publications

(2 citation statements)

References 31 publications

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“…The characteristics of guided waves have been explored in previous research by the authors of this paper [18][19][20][21]. As shown in Figure 1, the dispersive curves of guided waves for a steel bar with a diameter of 10 mm, and the wave structure diagram of the torsional wave T (0, 1) of a steel bar at 50 kHz, are plotted using the open-source program PCDISP and the GUIGUW 2.2 software, respectively.…”

Section: Fundamental Properties Of Torsional-mode Guided Wave T (0 1)mentioning

confidence: 99%

Damage Monitoring of Steel Bars Based on Torsional Guided Waves

Zheng,

Zhang,

Huang

2024

Sensors

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Ultrasonic guided waves represent a new development in the field of non-destructive testing. Longitudinal guided waves are mostly used to monitor the damage of steel bars, but the received signal is usually degraded and noisy owing to its dispersive propagation and multimodal behavior, making its implementation and location challenging. The torsional mode of T (0, 1) is not dispersive in the propagation of a steel bar and only produces circumferential displacement. It was chosen, in this study, to conduct guided wave-based damage monitoring on steel bars to reduce the signal processing complexity. The defects of steel bars, including circular surface defects, internal defects, and uniform damage defects, were thoroughly investigated, respectively, using numerical simulation. The waves were excited and received using the pitch-and-catch technique and the collected monitoring signals were processed using Hilbert transformation to highlight the amplitude and time-of-flight values of the wave signals, which were used for defect identification. In this paper, the reflectivity of guided waves is compared between torsional waves and longitudinal waves, in each case. The impact of defect size changes on damage monitoring is studied and the sensitivity of both the wave frequency and the wave mode (L and T) is also discussed. The results show that the monitoring method based on the torsional wave T (0, 1) is more sensitive to surface defects than the conventional method based on longitudinal waves. The reflectivity of the torsional wave T (0, 1) can be twice that of the longitudinal wave L (0, 1) when the depth of the defect in the circumferential grooves is less than 50% of the diameter of the steel bar. It is more sensitive to shallow surface defects within half of the bar’s radius, and it can also effectively identify defects under the conditions of the uniform damage defects of steel bars, even when the measurements are heavily noise-polluted. This proves the superiority of the torsional guided wave T (0, 1) in defect monitoring and provides a theoretical basis for the application of the torsional guided wave T (0, 1) in actual monitoring.

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Section: Fundamental Properties Of Torsional-mode Guided Wave T (0 1)mentioning

confidence: 99%

Damage Monitoring of Steel Bars Based on Torsional Guided Waves

Zheng,

Zhang,

Huang

2024

Sensors

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“…Hence, systematic investigation on the guided wave is a pre-requisite for choosing the appropriate excitation and mode type to improve the accuracy and efficiency of the NDT tests. The ultrasonic waves generated by the PZT patches, electro-acoustic transducer and lasers have been applied to the health monitoring of bond failure, the delamination in multi-layered plate-like composites, the debonding caused by corrosion of the steel bars and the defect in tubular waveguides [50,51,52,53,54,55,56,57,58]. The slender CFSTs specimens can be analyzed as rod-like waveguides since the diameter-height ratio is very small.…”

Section: Introductionmentioning

confidence: 99%

Interfacial Debonding Detection for Rectangular CFST Using the MASW Method and Its Physical Mechanism Analysis at the Meso-Level

Chen

Wang

et al. 2019

Sensors

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In this study, the transient multichannel analysis of surface waves (MASW) is proposed to detect the existence, the location and the length of interface debonding defects in rectangular concrete-filled steel tubes (CFST). Mesoscale numerical analysis is performed to validate the feasibility of MASW-based interfacial debonding detection. Research findings indicate that the coaxial characteristics in the Rayleigh wave disperse at the starting point of the debonding area and gradually restores at the end of the defect. For healthy specimens, the surface wave mode in CFST is closer to the Rayleigh wave. However, it can be treated as a Lamb wave since the steel plate is boundary-free on both sides in the debonding area. The displacement curves are further investigated with forward analysis to obtain the dispersion curves. The mesoscale numerical simulation results indicate that the propagation characteristic of the surface wave is dominated by the debonding defect. The detectability of interfacial debonding detection for rectangular CFST using the MASW approach is numerically verified in this study. The proposed MASW-based nondestructive testing technique can achieve bond-slip detection by comparing the variation trend of the coaxial characteristics in the time-history output signals and the dispersion curves obtained from the forward analysis, for avoiding misjudgment of the experimental observations.

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