Showing papers by "Gui Yun Tian published in 2023"
TL;DR: In this paper , a modified topology of WPT-based ECT (WPTECT) was used to characterize inclined angular RCF crack parameters in a rail-line material.
Abstract: Unavoidably, rolling contact fatigue (RCF) causes natural crack formation in the railhead, leading to rupture. Eddy current testing (ECT) is commonly used to quantify RCF cracks because of its higher sensitivity to a surface flaw, though with limited feature points. This article aims to characterize inclined angular RCF crack parameters in a rail-line material via a modified topology of Wireless Power Transfer (WPT)-based ECT (WPTECT) due to its magnetically coupled resonant for excitation and sensing circuits and utilize multiple resonance responses compared to other ECT. We experimentally designed and evaluated WPTECT and extracted multiple resonances and principal components analysis features to characterize inclined angular RCF cracks. The response minima point feature quantified the crack parameters incomparably; however, the second resonance feature is better than the first resonance. The reconstructed depth, opening width, and angle of the RCF cracks have a maximum correlation, R2 value of 96.4%, 93.1%, and 79.1%, respectively, and root mean square error of 0.05 mm, 0.08 mm, and 6.6°, respectively.
3 citations
TL;DR: In this article , an emissivity correction and thermal pattern reconstruction technique based on physical process modelling and thermal feature extraction, for eddy current pulsed thermography is proposed to address the pattern observation issues of thermography in both spatial and time domains.
Abstract: Emissivity variations are one of the most critical challenges in thermography technologies; this is due to the temperature calculation strongly depending on emissivity settings for infrared signal extraction and evaluation. This paper describes an emissivity correction and thermal pattern reconstruction technique based on physical process modelling and thermal feature extraction, for eddy current pulsed thermography. An emissivity correction algorithm is proposed to address the pattern observation issues of thermography in both spatial and time domains. The main novelty of this method is that the thermal pattern can be corrected based on the averaged normalization of thermal features. In practice, the proposed method brings benefits in enhancing the detectability of the faults and characterization of the materials without the interference of the emissivity variation problem at the object’s surfaces. The proposed technique is verified in several experimental studies, such as the case-depth evaluation of heat-treatment steels, failures, and fatigues of gears made of the heat-treated steels that are used for rolling stock applications. The proposed technique can improve the detectability of the thermography-based inspection methods and would improve the inspection efficiency for high-speed NDT&E applications, such as rolling stock applications.
2 citations
TL;DR: In this paper , a high-speed eddy current testing system is developed to experimentally investigate the influence of coil gap, detection speed, and the lift-off on the probe's response under moving conditions.
Abstract: Rolling contact fatigue (RCF) cracks online detection using eddy current testing (ECT) is in urgent demand. However, RCF cracks detection and evaluation in this way under moving conditions remains challenging due to the velocity effect in ECT. This paper aims to study the response of a transmitter-receiver eddy current probe to cracks under moving conditions and evaluate the depth and inclination angle of RCF cracks. In this paper, a high-speed eddy current testing system is developed to experimentally investigate the influence of coil gap, detection speed, and the lift-off on the eddy current probe’s response under moving conditions. In addition, the temporal and amplitude features of the eddy current signal are extracted to characterise the depth and inclination angle of the RCF cracks. The experimental results indicate the eddy current probe’s response can be improved by increasing the coil gap (coil centre distance) suitably, which can be done to compensate for the attenuation of the eddy current signal caused by detection speed and lift-off. The probe’s response hardly changes with an increase in detection speed when the driver and pick-up coils of the eddy current probe completely overlap. The crack depth and inclination angle can be evaluated under moving conditions.
TL;DR: In this paper , an inductance-to-digital (LDC) chip is used in eddy current testing for multiple parameter measurements including lift-off distance and defect detection, which has the potential to bridge the gaps in metrology of geometry, displacement measurement, and NDT&E for defect detection and material characterization.
Abstract: Sensors’ signal conditioning and digital interface are important for sensor technologies, digital transformation, and the Internet of Things (IoT) in particular. Frequency output sensors and inductance-to-digital converters (LDC) offer distinct advantages over Analog-to-Digital Converter (ADC) interfaces. To miniaturize the eddy current testing system and achieve multi-parameter measurements, this paper reviews eddy current signal conditioning and digital interfaces in the field of displacement sensors and non-destructive tests & evaluation (NDT&E). After review and comparison of different signal conditioning and digital interfaces, the LDC chip is used in eddy current testing for multiple parameter measurements including lift-off distance and defect detection. An LDC-based integrative eddy current non-destructive testing method is proposed. The LDC chip provides AC to drive the LC resonator composed of the sensor coil and the parallel capacitor. By measuring the resonance frequency and parallel resistance (Rp) of the LC resonator, the simultaneous measurement of the lift-off distance and the defect is achieved. Based on the method, the testing experiments of two kinds of specimens made of aluminium and steel were carried out under different lift-offs. Experimental results show that both parameters of frequency and Rp of the LC resonator can intuitively reflect the defect depth and lift-off. Frequency- Rp curves can be used to quantify defect depth and lift-off distance and differentiate the material. This work also illustrates an integrated approach of signal conditioning and digital interface for multiple parameters or feature measurement for integrated eddy current NDT&E. The work opens a new way for addressing multiple parameter measurements of eddy current NDT & E including lift-off estimation and defect characterization via digital interfaces. It has the potential to bridge the gaps in metrology of geometry, displacement measurement, and NDT&E for defect detection and material characterization.
TL;DR: In this article , the authors proposed a wireless inductive-capacitive (LC) resonance sensing approach for non-contact measurement of wheel-rail contact forces, which consists of a dual-layer rectangular inductance coil and a parallel capacitor.
Abstract: Wheel-rail contact force measurement is one of the key issues in rolling stock monitoring. Traditional methods using strain gauges are a relative measurement, which require strong bonding on the wheel webs with complicated telemetry transmission systems. This paper proposes a wireless inductive-capacitive (LC) resonance sensing approach for non-contact measurement of wheel-rail contact forces. The proposed LC resonance sensor is low-cost, high sensitivity, and consists of a dual-layer rectangular inductance coil and a parallel capacitor. Validation using a standard dog-bone specimen tested on a universal testing machine was performed, with the resonant frequency of the proposed LC resonance sensor increasing monotonically with loading force. Investigation of lift-off and aspect ratio of the inductance coil shows that lower lift-off and lower aspect ratio offer better sensitivity. The proposed LC resonance sensing with LDC chip approach has great potential for rolling stock monitoring.
TL;DR: In this article , a hybrid magnetic sensing structure for measuring eddy current, alternating electromagnetic (EM) field, Barkhausen noise, and incremental permeability signals is designed and instrumented.
Abstract: Stress measurement and evaluation of ferromagnetic components using electromagnetic nondestructive testing (ENDT) are affected by the microstructure properties of the material, such as inhomogeneity and anisotropy. This leads to magnetic induction sensitivity in the variety of both the stress and microstructure. To address this challenge, a hybrid magnetic sensing structure for measuring eddy current (EC), alternating electromagnetic (EM) field, Barkhausen noise, and incremental permeability signals is designed and instrumented. Additionally, a stress detection verification test for oriented silicon steel samples is carried out, and a comparison with commercial instruments in terms of sensitivity and repeatability is performed. The results show that the proposed sensor has advantages in detection repeatability, good sensitivity as well as high signal-to-noise (SNR) for MBN features, which brings potential in stress characterization and assessment.
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TL;DR: In this article , the authors derived the resonance frequency of the Coil-interdigital electrode (IDE) sensor both in series and parallel topological structure, and analyzed the sensitivity of frequency to IDE capacitance.
Abstract: In this article, the frequency sensitivity of the Coil-interdigital electrode (IDE) sensor in different integrated topologies is studied. In particular, the expression of the resonance frequency of the Coil-IDE sensor both in series and parallel topological structure is derived. The sensitivity of frequency to IDE capacitance was analyzed, and two new results can be found 1) due to the existence of coil winding capacitance and grounding capacitance, the Coil-IDE topology circuit has been changed, which causes the Coil-IDE parallel topology structure has a higher frequency sensitivity than series and 2) not only the topology structure but also the parameters such as coil inductance and IDE capacitance have the regulatory effect on the frequency sensitivity. After analysis, an experiment of a Coil-IDE humidity sensor was applied to verify the presented results. The parallel frequency of the Coil-IDE parallel structure having a higher sensitivity was confirmed. The error of the proposed formula predicting the regulatory effect of parameters on frequency sensitivity was discussed. The error is as low as 7.57%, which shows the beneficial aspect of the integrated design of Coil-IDE sensor both in topological structure and parameters.