Monitoring of air voids at plastic-metal interfaces by terahertz radiation

Pałka, Norbert; Rybak, Andrzej; Jakubowski, Tomasz; Florkowski, Marek; Kowalski, Marcin; Zagrajek, Przemysław; Życzkowski, M.; Ciurapiński, W.; Jodłowski, L.; Walczakowski, Michał

doi:10.1016/j.infrared.2019.103119

Cited by 7 publications

(3 citation statements)

References 15 publications

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“…Among the other methods which found application in the detection of voids in polymers and PMCs, one can distinguish a class of terahertz testing (TT) techniques with a resolution on a submillimeter level. This includes terahertz time-domain spectroscopy and a frequency modulation continuous wave method, which seems to be a promising approach for such a class of problems with prior proven effectiveness [6,8,[53][54][55][56][57][58]. However, the experimental setup is usually very complicated and costly, while the penetration capability is insufficient in the case of thick structures [6], as well as the technique is limited to electrically inactive polymers.…”

Section: Introductionmentioning

confidence: 99%

Quality Control Approach for the Detection of Internal Lower Density Areas in Composite Disks in Industrial Conditions Based on a Combination of NDT Techniques

Katunin

Dragan

Nowak³

et al. 2021

Sensors

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Voids in polymer matrix composites are one of the most common manufacturing defects, which may influence the mechanical properties and structural behavior of the final parts made of composites by various manufacturing methods. Therefore, numerous non-destructive testing (NDT) techniques were developed and applied for quality control and in-service testing of such structures. In this paper, the authors analyzed various alternatives to the reference technique, X-ray computed tomography (XCT) NDT, which is used for industrial testing of composite disks having defects in the form of the lower density areas. Different candidates, namely: vibration-based testing, infrared thermography, vibro-thermography, as well as ultrasonic testing were analyzed in terms of their sensitivity and technical feasibility. The quality of the results, the complexity of the testing procedure, time and labor consumption, and the cost of the equipment were analyzed and compared with the reference technique. Based on the conducted research the authors finally proposed a hybrid approach to quality control, using a combination of two NDT techniques–infrared thermography (for initial scanning and detection of near-surface defects) and ultrasonic testing (for a more detailed analysis of products that pass the first testing procedure). It allowed for replacing the costly XCT diagnostics with a much cheaper, but almost equally effective, alternative.

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Section: Introductionmentioning

confidence: 99%

Quality Control Approach for the Detection of Internal Lower Density Areas in Composite Disks in Industrial Conditions Based on a Combination of NDT Techniques

Katunin

Dragan

Nowak³

et al. 2021

Sensors

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“…In this study, THz NDT of hollowing deterioration in a typical sandstone open-air stone cultural relic of Yungang Grottoes was performed by experimental and theoretical research of hollowing deterioration. Based on the relation between the relative time delay of three reflected pulses and the hollowing thickness of the samples [27][28][29][30], the SVMbased [31] hollowing deterioration prediction model (SVM-HDPM) for stone relics can be established by using a leastsquares version of SVM (LS-SVM). By using the model, the hollowing thickness in stone relics could be accurately predicted and discovered when the THz data of hollowing deterioration were input into the SVM-HDPM, which can have high accuracy and validity proved by the experimental results.…”

Section: Introductionmentioning

confidence: 99%

Highly sensitive Terahertz non-destructive testing technology for stone relics deterioration prediction using SVM-based machine learning models

Meng

Huang

et al. 2021

Preprint

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The hollowing deterioration of stone relics required effective non-destructive testing (NDT) methods for their timely restoration and maintenance. To this end, a new NDT method based on terahertz (THz) technology by using support vector machine (SVM)-based machine learning models was developed to assess and diagnose the hollowing deterioration of the Yungang Grottoes. According to experiment design, a series of hollowing deterioration samples with various thicknesses of hollowing deterioration were prepared and then measured by using THz time-domain spectroscopy (THz-TDS). Based on the THz-TDS results of 30 randomly selected samples, a SVM-based hollowing deterioration prediction model (SVM-HDPM) was established by analyzing the relationship between the hollowing samples and the THz spectral information. The reliability and accuracy of the model was further proved by verified and compared with using the THz spectral data of the remaining 10 samples. The experimental results with the linear kernel function greatly demonstrated that the SVM-HDPM can have superior prediction accuracy, implying that the model is feasible for the prediction the hollowing deterioration of the stone relics. Moreover, one data preprocess was introduced into SVM-HDPM to meet the needs of field-based test. The predicted results of five different hollowing deterioration with different flaked stone thickness revealed good performance with very low mean square error (MSE) value. Therefore, it is believed that the proposed method can be regarded as an effective NDT technique with practical applications in analyzing cultural relics and have promising future prospects in inspection stone relics-like ancient heritage for hidden flaws.

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“…In this study, THz NDT of hollowing deterioration in a typical sandstone open-air stone cultural relic of Yungang Grottoes was performed by experimental and theoretical research of hollowing deterioration. Based on the relation between the relative time delay of three reflected pulses and the hollowing thickness of the samples [28][29][30][31], the SVM-based hollowing deterioration prediction model (SVM-HDPM) for stone relics can be established by using LS-SVM. By using the model, the hollowing thickness in stone relics could be accurately predicted and discovered when the THz data of hollowing deterioration were input into the SVM-HDPM, which can have high accuracy and validity proved by the experimental results.…”

Section: Introductionmentioning

confidence: 99%

Highly Sensitive Terahertz Non-destructive Testing Technology for Stone Relics Deterioration Prediction Using SVM-Based Machine Learning Models

Meng

Liu

et al. 2020

Preprint

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The hollowing deterioration of stone relics required effective non-destructive testing (NDT) methods for their timely restoration and maintenance. To this end, a new NDT method based on terahertz (THz) technology by using support vector machine (SVM)-based machine learning models was developed to assess and diagnose the hollowing deterioration of the Yungang Grottoes. According to experiment design, a series of hollowing deterioration samples with various thicknesses of hollowing deterioration were prepared and then measured by using THz time-domain spectroscopy (THz-TDS). Based on the THz-TDS results of 30 randomly selected samples, a SVM-based hollowing deterioration prediction model (SVM-HDPM) was established by analyzing the relationship between the hollowing samples and the THz spectral information. The reliability and accuracy of the model was further proved by verified and compared with using the THz spectral data of the remaining 10 samples. The experimental results with the linear kernel function greatly demonstrated that the SVM-HDPM can have superior prediction accuracy with a mean square error (MSE) of 3.303E-4, implying that the model is feasible for the prediction the hollowing deterioration of the stone relics. Moreover, one data preprocess was introduced into SVM-HDPM to meet the needs of field-based test. The predicted results of five different hollowing deterioration with different flaked stone thickness revealed good performance with MSE value as low as 4.46E-4. Therefore, it is believed that the proposed method can be regarded as an effective NDT technique with practical applications in analyzing cultural relics and have promising future prospects in inspection stone relics-like ancient heritage for hidden flaws.

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Monitoring of air voids at plastic-metal interfaces by terahertz radiation

Cited by 7 publications

References 15 publications

Quality Control Approach for the Detection of Internal Lower Density Areas in Composite Disks in Industrial Conditions Based on a Combination of NDT Techniques

Quality Control Approach for the Detection of Internal Lower Density Areas in Composite Disks in Industrial Conditions Based on a Combination of NDT Techniques

Highly sensitive Terahertz non-destructive testing technology for stone relics deterioration prediction using SVM-based machine learning models

Highly Sensitive Terahertz Non-destructive Testing Technology for Stone Relics Deterioration Prediction Using SVM-Based Machine Learning Models

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