Nondestructive Evaluation of Rubber Composites Using Terahertz Time Domain Spectroscopy

Xu, Fengyuan; Mu, Qiyuan; Li, L. J.; Ding, Yang; Xia, Baolin

doi:10.5604/01.3001.0010.7799

Cited by 12 publications

(5 citation statements)

References 5 publications

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“…Finally, the THz‐TDS system was used to visualise the thickness distribution of the rubber sample. The delamination defects of the sample were successfully detected by combining THz imaging of the internal defects of different bonding structures with spectroscopic testing and visual imaging of a three‐layer bonding structure [95, 96]. Previous studies also reported using terahertz technology to detect defects in simplified models of vehicle cable terminals.…”

Section: Online Monitoring and Defect Detection Methodsmentioning

confidence: 99%

Review of condition monitoring and defect inspection methods for composited cable terminals

Cao

et al. 2023

High Voltage

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Composited cable terminals are critical for reliable power delivery of traditional and traction power supply systems. During its operation, the cable terminal continually undergoes complex circumstances where humidity, temperature, field strength, mechanical stress and other factors continuously change at different levels. In extreme cases, defects or even failures may occur in the cable terminals, leading to catastrophic accidents. This makes the condition monitoring and defect detection of composited cable terminals become an imperative need for the power industry. The “state‐of‐the‐art” technology of cable terminal condition assessment is focussed and a systematic review of the current research progress of cable terminal condition assessment from the operation circumstances to failure mechanisms is provided. It covers both online/offline condition monitoring methods and defects detection approaches. In addition, challenges and future research directions for cable terminal condition assessment are also addressed. It is concluded that the non‐destructive and non‐intrusive methods like terahertz imaging and ultrasonic testing, and multi‐source information fusion methods as well as the digital twin technology have been gaining popularity for cable terminal defect inspection. It is expected the presented work can provide a global field of vision for further advancement of both scholars and industrial engineers in this field.

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Section: Online Monitoring and Defect Detection Methodsmentioning

confidence: 99%

Review of condition monitoring and defect inspection methods for composited cable terminals

Cao

et al. 2023

High Voltage

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“…As one of the three major polymer materials, rubber has high elasticity than metal, high mechanical strength and good bending resistance. Because of its unique properties, rubber is widely used in medical and health, power communication, civil engineering and other fields [22]. Glass fiber reinforced composites are widely used in the bearing and electromagnetic wave transmission structures of unmanned aerial vehicles due to their excellent strength-weight ratio, aerodynamic performance and microwave permeability [23].…”

Section: Imaging Samples Experimental Methods and Image Processing Sample Introduction And Experimental Setupmentioning

confidence: 99%

A Novel Method for the Enhancement of Composite Materials’ Terahertz Image Using Unsharp Masking and Guided Filtering Technology

Zuo

Zhao

et al. 2021

Front. Phys.

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When terahertz imaging technology is used for the nondestructive testing of composite materials, the signal is often affected by the experimental environment and internal noise of the system, as well as the absorption and scattering effect of the tested materials. The obtained image has degradation phenomena such as low contrast, poor resolution of small targets and blurred details. In order to improve the image quality, this paper proposes a novel method for the enhancement of composite materials’ terahertz image by using unsharp masking and guided filtering technology. The method includes the processing steps of hard threshold shrinkage denoising based on discrete wavelet transform, amplitude imaging, unsharp masking, guided filtering, contrast stretching, and pseudo-color mapping. In this paper, these steps are reasonably combined and optimized to obtain the final resulting image. To verify the effectiveness of the proposed method, a 150–220 GHz high frequency terahertz frequency modulated radar imaging system was used to image three commonly used sandwich structure composites, and the enhancement processing were carried out. The resulting images with significantly enhanced contrast, detail resolution and edge information were obtained, and the prefabricated defects were all detected; Five objective evaluation indexes including standard deviation, mean gradient, information entropy, energy gradient and local contrast were used to compare and analyze the processing results of different image enhancement methods. The subjective and objective evaluation results showed that the proposed method can effectively suppress the noise in terahertz detection signals, enhance the ability of defect detection and positioning, and improve the accuracy of detection. The proposed method in this paper is expected to play a positive role in improving the practicability of terahertz imaging detection technology and expanding its application fields.

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“…Although the D-S evidence theory has been a promising and popular approach for NDE data fusion especially in recent years, 22 the computation of the value of the mass functions remains largely an unsolved challenge (i.e., there is currently no unique solution to all applications). Quite a few strategies have been documented in the literature to determine this parameter, 97,98 but studies argue that the process to calculate the mass value should always be as objective as possible to guarantee the accurate representation of the different NDE data sources. 18 Additional issues include but are not limited to the exponential complexity of computations (in the general worst-case scenario) as well as the likelihood of obtaining counterintuitive results when fusing conflicting data.…”

Section: Dempster-shafer Evidence Theorymentioning

confidence: 99%

Critical insights into the state‐of‐the‐art NDE data fusion techniques for the inspection of structural systems

Nsengiyumva

Zhong

Luo

et al. 2021

Structural Contr & Hlth

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In recent years, the demand for reliable and accurate nondestructive evaluation (NDE) of structural systems has been growing and several nondestructive testing (NDT) techniques are being combined to address the issues of uncertainty in the testing results. However, the synergistic combination of multiple NDT techniques and the interpretation of the testing results require the ability to process and analyze data from several sources, a process that is referred to as "data fusion." The latter has received considerable attention since the beginning of the 21st century, thanks to the advances in sensor technologies and data acquisition systems. Also, the new era of "Big Data" where heterogeneous data are measured by different sensors and processed for a unified purpose is another factor contributing to this rapid development and the establishment of new NDT opportunities. This article reviews the recent studies involving NDE data fusion for the inspection of structures and examines the state-of-the-art mathematical expressions used in different fusion algorithms. Challenges in the handling of the NDE data and the application of fusion algorithms are also identified and discussed. A generic framework of applying NDE data fusion is described, and a roadmap for potential research prospects in NDE data fusion is provided.data fusion, diagnostic and prognostic health monitoring (DPHM), multisensor fusion and integration (MFI), nondestructive evaluation (NDE), structural health monitoring (SHM), structural systems | INTRODUCTIONEngineering structures are manufactured through multivariable processes and can easily develop defects during the manufacturing process and suffer from various issues (e.g., inappropriate usages, progressive aging, impact damage, excessive loading, and natural hazards such as earthquakes, hurricanes, etc.) during their service life. 1,2 To this end, several nondestructive evaluation (NDE) techniques have been devised (e.g., ultrasonic testing, infrared thermography, terahertz spectrometry, and imaging) to inspect these structures and their corresponding components to ensure they are free from defects and that their structural integrity is maintained throughout their service life. [1][2][3][4] At the manufacturing stage, NDE determines the structure's fitness to accomplish its intended function, and during the service stage, it determines the structure's health status, monitors the damage mechanism,

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Nondestructive Evaluation of Rubber Composites Using Terahertz Time Domain Spectroscopy

Cited by 12 publications

References 5 publications

Review of condition monitoring and defect inspection methods for composited cable terminals

Review of condition monitoring and defect inspection methods for composited cable terminals

A Novel Method for the Enhancement of Composite Materials’ Terahertz Image Using Unsharp Masking and Guided Filtering Technology

Critical insights into the state‐of‐the‐art NDE data fusion techniques for the inspection of structural systems

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