Practical Visualization of Local Vibration Data Collected over Large Concrete Elements

Oh, Taegon; Popovics, John S.

doi:10.1111/mice.12065

Cited by 8 publications

(6 citation statements)

References 21 publications

(33 reference statements)

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“…Detailed theory can be found in [12]. Oh & Popovics [13,14] found that the flexural vibration frequency for significant near-surface delaminations (greater than 160 mm x 160 mm) falls below 6 kHz in most cases. In contrast, the thickness stretch resonance frequency does not usually fall below 6 kHz because the plate thickness, for example of a bridge deck, is normally in the range of (20 to 30) cm.…”

Section: Theory and Methodsmentioning

confidence: 99%

Delamination Detection in Concrete Plates using a Laser Ablation Impact Echo Technique

Scherr¹,

Dallinger²,

Püschel³

et al. 2022

eJNDT

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This study investigates the detection of delaminations in concrete plates using non-contact laser ablation instead of the conventional hammer excitation. Tests were performed on two specimens of which one had an artificial delamination. 5 mm to 15 mm diameter steel tip hammers were used as a reference source and compared to a 7 ns pulsed 1064 nm Nd:YAG laser with 150 mJ pulse energy. Signals were recorded by surface- mounted accelerometers and in air by microphones and a laser Doppler vibrometer. Frequencies up to 150 kHz are excited with a broad frequency spectrum and little energy compared to the narrower frequency spectra of the hammers. The characteristic thickness resonance frequency of the intact plates can be accurately detected by the hammer excitation. The laser can excite low frequency flexural vibration modes over a shallow delamination at 3 cm depth, but does not excite the thickness resonance frequency. The low frequency flexural vibrations are verified by numerical natural frequency analysis.

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Section: Theory and Methodsmentioning

confidence: 99%

Delamination Detection in Concrete Plates using a Laser Ablation Impact Echo Technique

Scherr¹,

Dallinger²,

Püschel³

et al. 2022

eJNDT

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show abstract

“…These distances are not sufficient to detect smaller defects. Contactless system ACIE provides the ability to implement research on denser grid, as well as the duration of each test ACIE is much shorter [7], which provides greater accuracy.…”

Section: Impact Echo and Air-coupled Impact-echo Methods Of Ndtmentioning

confidence: 99%

“…Application of proposed data of manipulation and visualization technique to IE data collected from two different reinforced concrete samples demonstrates improved near-surface delamination detection as compared with conventional data formats [7].…”

Section: Software Methodsmentioning

confidence: 99%

Review of the Air-Coupled Impact-Echo Method for Non-Destructive Testing

Nowotarski

Dubas

Milwicz

2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. The article presents the general idea of Air-Coupled Impact-Echo (ACIE) method which is one of the non-destructive testing (NDT) techniques used in the construction industry. One of the main advantages of the general Impact Echo (IE) method is that it is sufficient to access from one side to that of the structure which greatly facilitate research in the road facilities or places which are difficult to access and diagnose. The main purpose of the article is to present state-of-the-art related to ACIE method based on the publications available at Thomson Reuters Web of Science Core Collection database (WOS) with the further analysis of the mentioned methods. Deeper analysis was also performed for the newest publications published within last 3 years related to ACIE for investigation on the subject of main focus of the researchers and scientists to try to define possible regions where additional examination and work is necessary. One of the main conclusions that comes from the performed analysis is that ACIE methods can be widely used for performing NDT of concrete structures and can be performed faster than standard IE method thanks to the Air-coupled sensors. What is more, 92.3% of the analysed recent research described in publications connected with ACIE was performed in laboratories, and only 23.1% in-situ on real structures. This indicates that method requires further research to prepare test stand ready to perform analysis on real objects outside laboratory conditions. Moreover, algorithms that are used for data processing and later presentation in ACIE method are still being developed and there is no universal solution available for all kinds of the existing and possible to find defects, which indicates possible research area for further works. Authors are of the opinion that emerging ACIE method could be good opportunity for ND testing especially for concrete structures. Development and refinement of test stands that will allow to perform in-situ tests could shorten the overall time of the research and with the connection of implementation of higher accuracy algorithms for data analysis better precision of defects localization can be achieved.

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“…Detailed theory can be found in [12]. Oh & Popovics [13,14] found that the flexural vibration frequency for significant near-surface delaminations (greater than 160 mm× 160 mm) falls below 6 kHz in most cases. In contrast, the thickness stretch resonance frequency does not usually fall below 6 kHz because the plate thickness, for example, of a bridge deck, usually is in the range of (20 to 30) cm.…”

Section: Impact Echomentioning

confidence: 99%

“…Fig 14. Mean FFT of 14 signals recorded by PCB 352C33 accelerometer (Acc), PCB 378B02 microphone (Mic), and laser Doppler vibrometer (LDV) using the surface test configuration.…”

mentioning

confidence: 99%

Detection of Delaminations in Concrete Plates Using a Laser Ablation Impact Echo Technique

et al. 2023

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This study investigates the non-destructive detection of delaminations in concrete plates using non-contact laser ablation, instead of the conventional hammer excitation, as part of the impact echo method. We performed tests on five concrete specimens of different sizes, two of which contained artificial delaminations. A range of steel ball hammers was used as reference impulse sources, the responses of which were compared with wave excitation generated by a 7 ns pulsed 1064 nm Nd:YAG laser with 150 mJ pulse energy. Signals were recorded by surface-mounted accelerometers and two contactless methods: microphones and a laser Doppler vibrometer. The laser generates frequencies across a broad range of frequencies (0 to 150 kHz) but with much less energy than the hammers' narrower frequency spectra; the laser pulse energy transferred into the specimen is 0.07 mJ, corresponding to about 0.5 ‰ of the impulse source energy. Because of this, the thick intact plates' characteristic thickness stretch resonance frequency can be reliably detected by the hammer excitations but not when using laser excitation. However, the laser can excite low-frequency flexural vibration modes over a shallow delamination at 3 cm depth. The low-frequency flexural vibration results are verified by numerical natural frequency analysis.

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Practical Visualization of Local Vibration Data Collected over Large Concrete Elements

Cited by 8 publications

References 21 publications

Delamination Detection in Concrete Plates using a Laser Ablation Impact Echo Technique

Delamination Detection in Concrete Plates using a Laser Ablation Impact Echo Technique

Review of the Air-Coupled Impact-Echo Method for Non-Destructive Testing

Detection of Delaminations in Concrete Plates Using a Laser Ablation Impact Echo Technique

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