Detection Effect of Resonance Frequency of Both Laser Doppler Vibrometer and Internal Defect of Concrete Structure by Spatial Spectral Entropy

Sugimoto, Kazuko; Sugimoto, Takashige; Utagawa, Noriyuki; Kuroda, Chitose

doi:10.1109/ultsym.2018.8580050

Cited by 7 publications

(9 citation statements)

References 4 publications

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“…For a fully remote and automated process the noncontact excitation of the defect is crucial. The method of exciting resonance vibrations via directed sound waves and detecting them via an LDV could be shown but this approach also suffers from a low measurement rate [5].…”

Section: Introductionmentioning

confidence: 99%

Laser-based measurement system for the detection of delamination in tunnel linings

Vierhub-Lorenz¹,

Werner²,

Weiher³

et al. 2023

Optical Measurement Systems for Industrial Inspection XIII

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Tunnel inspections require the detection of deformations in the tunnel geometry, cracks, delamination, and water inflow. Solutions for an automated detection of deformations, cracks and water inflow already exist and typically comprise mobile laser-scanners and cameras combined with deep learning methods. Delaminations on the other hand are often not visible on the surface and can't be detected using these methods. The detection of delamination in tunnel linings is therefore up to date performed by manual hammering and acoustic detection. The results are time consuming and labor-intensive inspections, subjective measurements, poor comparisons over epochs and a low degree of digitization. We present a concept of a novel system that aims to replace the manual hammering for acoustic delamination detection using a remote sensing approach. A strong, pulsed laser serves as a hammer and creates a plasma induced shockwave on the concrete surface. If a delamination is present this shockwave excites characteristic, resonant vibrations. A second, narrow-linewidth laser is employed in a customized laser doppler vibrometer setup to remotely detect these vibrations via a coherent measurement technique. In combination with laser scanners and cameras, the laser based remote sensing technique has the potential to help automating the process of tunnel inspections by delivering objective data that can be used in deep learningbased evaluation methods and for building information modeling (BIM) compliant assessment. A first mobile prototype for measurements outside the lab has been developed and is being presented in detail.

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Section: Introductionmentioning

confidence: 99%

Laser-based measurement system for the detection of delamination in tunnel linings

Vierhub-Lorenz¹,

Werner²,

Weiher³

et al. 2023

Optical Measurement Systems for Industrial Inspection XIII

View full text Add to dashboard Cite

show abstract

“…In addition, since the temperature distribution is measured using a heater, it is not suitable for work in high places. In our previous studies, defect detection algorithms, 12,13) vibration energy ratio, 14) spectral entropy, 15,16) evaluation of healthy parts 17) have been proposed as methods for evaluating inspection results. In addition, sound waves have also been studied in order to improve the efficiency of inspection and the signal-to-noise ratio.…”

Section: Introductionmentioning

confidence: 99%

Research on improvement of defect detection accuracy by resonance judgment for noncontact acoustic inspection method by acoustic irradiation-induced vibration

Nakagawa

Sugimoto

et al. 2022

Jpn. J. Appl. Phys.

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Noncontact acoustic inspection methods using acoustic irradiation induced vibration and laser Doppler vibrometer that can perform defect exploration from a distance are being studied. This method has the feature that it can measure a wide range of measurement objects such as composite materials used for aerospace as well as concrete structures such as tunnels and bridges without contact. From the experimental results, it was found that the increase in noise level due to the decrease in the return light of the laser due to the condition of the measurement surface causes a decrease in the estimation accuracy of defect exploration. Therefore, it has been clarified that the detection accuracy of the defect position can be improved by devising a resonance judgement process for discriminating the signal and noise due to the resonance of the defect portion.

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“…For example, Yasuda et al induced vibrations on the surface of concrete tunnels by laser ablation and used laser vibrometry to measure vibration signals to detect the health of tunnel linings [ 13 , 14 ]. Using remote directional acoustic radar as the sound generation source, Sugimoto et al investigated a method to detect internal defects in underground tunnels and viaducts by laser vibrometry [ 15 , 16 ]. However, although the methods mentioned above can effectively distinguish between abnormal and normal areas inside the concrete, it is difficult to effectively classify the types of typical defects in concrete, such as segregation, cavities, foreign matter, and so on.…”

Section: Introductionmentioning

confidence: 99%

Concrete Multi-Type Defect Classification Algorithm Based on MSSMA-SVM

et al. 2022

Sensors

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In order to realize the automatic classification of internal defects for non-contact nondestructive testing of concrete, a concrete multi-type defect classification algorithm based on the mixed strategy slime mold algorithm support vector machine (MSSMA-SVM) was proposed. The concrete surface’s vibration signal was obtained using a laser Doppler vibrometer (LDV) for four classification targets for no defect, segregation, cavity, and foreign matter concrete classification targets. The wavelet packet transform (WPT) decomposes the detected signals to get information on different frequency bands. The energy ratio change rate, energy ratio, and wavelet packet singular entropy of each node after the WPT were used as the feature input of MSSMA-SVM. The experimental results show that the designed MSSMA-SVM classifier can accurately detect the type, which provides a practical algorithm for classifying concrete defects by laser vibration measurement.

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Detection Effect of Resonance Frequency of Both Laser Doppler Vibrometer and Internal Defect of Concrete Structure by Spatial Spectral Entropy

Cited by 7 publications

References 4 publications

Laser-based measurement system for the detection of delamination in tunnel linings

Laser-based measurement system for the detection of delamination in tunnel linings

Research on improvement of defect detection accuracy by resonance judgment for noncontact acoustic inspection method by acoustic irradiation-induced vibration

Concrete Multi-Type Defect Classification Algorithm Based on MSSMA-SVM

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