scholarly journals Reduction of Coil-Crack Angle Sensitivity Effect Using a Novel Flux Feature of ACFM Technique

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 201
Author(s):  
Ruochen Huang ◽  
Mingyang Lu ◽  
Ziqi Chen ◽  
Wuliang Yin
Keyword(s):  
Magnetic Field ◽  
Crack Detection ◽  
Sine Wave ◽  
Destructive Testing ◽  
Computation Efficiency ◽  
Detection Approach ◽  
Excitation Coil ◽  
Lift Off ◽  
The Magnetic Field ◽  
Sensor Probe

Alternating current field measurement (ACFM) testing is one of the promising techniques in the field of non-destructive testing with advantages of the non-contact capability and the reduction of lift-off effects. In this paper, a novel crack detection approach was proposed to reduce the effect of the angled crack (cack orientation) by using rotated ACFM techniques. The sensor probe is composed of an excitation coil and two receiving coils. Two receiving coils are orthogonally placed in the center of the excitation coil where the magnetic field is measured. It was found that the change of the x component and the peak value of the z component of the magnetic field when the sensor probe rotates around a crack followed a sine wave shape. A customized accelerated finite element method solver programmed in MATLAB was adopted to simulate the performance of the designed sensor probe which could significantly improve the computation efficiency due to the small crack perturbation. The experiments were also carried out to validate the simulations. It was found that the ratio between the z and x components of the magnetic field remained stable under various rotation angles. It showed the potential to estimate the depth of the crack from the ratio detected by combining the magnetic fields from both receiving coils (i.e., the x and z components of the magnetic field) using the rotated ACFM technique.

scholarly journals Reduction of Coil-Crack Angle Sensitivity Effect Using a Novel Flux Feature of ACFM Technique

2021 ◽  
Author(s):  
Ruochen Huang ◽  
Mingyang Lu ◽  
Ziqi Chen ◽  
Wuliang Yin
Keyword(s):  
Magnetic Field ◽  
Crack Detection ◽  
Sine Wave ◽  
Destructive Testing ◽  
Computation Efficiency ◽  
Detection Approach ◽  
Excitation Coil ◽  
Lift Off ◽  
The Magnetic Field ◽  
Sensor Probe

Alternating current field measurement (ACFM) testing is one of promising techniques in the field of non-destructive testing with advantages of the non-contact capability and the reduction of lift-off effects. In this paper, a novel crack detection approach is proposed to reduce the effect of the angled crack (cack orientation) by using rotated ACFM techniques. The sensor probe is composed of an excitation coil and two receiving coils. Two receiving coils are orthogonally placed in the centre of the excitation coil where the magnetic field is measured. It is found that the change of the x component and the peak value of the z component of the magnetic field when the sensor probe rotates around a crack follows a sine wave shape. A customised accelerated finite element method solver programmed in MATLAB is adopted to simulate the performance of the designed sensor probe which can significantly improve the computation efficiency due to the small crack perturbation. The experiments have also been carried out to validate the simulations. It is found that the ratio between the z and x components of the magnetic field remains stable under various rotation angles. It shows the potential to estimate the depth of the crack from the ratio detected by combining the magnetic fields from both receiving coils (i.e., the x and z components of the magnetic field) using the rotated ACFM technique.

scholarly journals Magnetic Recording Method (MRM) for Nondestructive Evaluation of Ferromagnetic Materials

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 630
Author(s):  
Tomasz Chady ◽  
Ryszard D. Łukaszuk ◽  
Krzysztof Gorący ◽  
Marek J. Żwir
Keyword(s):  
Magnetic Field ◽  
Magnetic Recording ◽  
Permanent Magnets ◽  
Steel Structure ◽  
Standard Technique ◽  
Magnetic Field Measurement ◽  
Destructive Testing ◽  
Recording Method ◽  
Nondestructive Testing Method ◽  
The Magnetic Field

This paper proposes and experimentally investigates a novel nondestructive testing method for ferromagnetic elements monitoring, the Magnetic Recording Method (MRM). In this method, the inspected element must be magnetized in a strictly defined manner before operation. This can be achieved using an array of permanent magnets arranged to produce a quasi-sinusoidal magnetization path. The magnetic field caused by the original residual magnetization of the element is measured and stored for future reference. After the operation or loading, the magnetic field measurement is repeated. Analysis of relative changes in the magnetic field (for selected components) allows identifying applied stress. The proposed research methodology aims to provide information on the steel structure condition unambiguously and accurately. An interpretation of the results without referring to the original magnetization is also possible but could be less accurate. The method can be used as a standard technique for NDT (Non-Destructive Testing) or in structural health monitoring (SHM) systems.

Characterization of Magnetic Field in Crack Propagation Stage and Application to Non-Destructive Evaluation

2020 ◽  
Author(s):  
Sheng Bao ◽  
Zhengye Zhao ◽  
Qiang Luo ◽  
Jian Yang
Keyword(s):  
Magnetic Field ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Propagation ◽  
Magnetic Measurement ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Non Destructive ◽  
The Magnetic Field

Abstract Monitoring of fatigue crack propagation is very important in industrial fields. Stress-induced magnetic measurement is a newly developed non-destructive testing technique which can detect early failure of ferromagnetic materials in service. A lot of experiments demonstrate that magnetic measurement is more sensitive compared with other non-destructive testing technologies. In order to explore the correlation between crack propagation and magnetic hysteresis under cyclic stress in X70 pipeline steel, a series of stress-controlled tests were carried out and the changes in magnetic field around cracks during their propagation process were observed throughout the tension-tension fatigue tests. The variations of magnetic field and stress intensity factor K in the crack propagation stage were studied. The results obtained allowed the division of the magnetic behavior of the investigated steels into three stages corresponding to three distinct crack propagation stages. It was found that the magnetic field varies with crack propagation, and the stress intensity factor K increased with the increase of loading cycles. A strong correlation between the variation of the magnetic field and stress intensity factor was recognized, regardless of the loading conditions, maximum load or stress ratio. The results suggest that non-destructive evaluation of fatigue cracks would be possible using this relationship.

Development of Numerical Analysis Software for the NDE by Using Dipole Model

2007 ◽  
Vol 353-358 ◽  
pp. 2383-2386
Author(s):  
Jin Yi Lee ◽  
Jong Woo Jun ◽  
Ji Seong Hwang ◽  
Se Hoon Lee
Keyword(s):  
Magnetic Field ◽  
Numerical Analysis ◽  
Field Distribution ◽  
Electrical Signal ◽  
Dipole Model ◽  
Magnetic Field Distribution ◽  
Analysis Software ◽  
Magnetization Direction ◽  
Lift Off ◽  
The Magnetic Field

The magnetic field distribution around a crack can be calculated more easily and quickly by using a dipole model than finite element method (FEM). This paper reports the development of numerical analysis software that uses an improved dipole model to analyze the magnetic field around cracks. The preprocessor in this software includes the crack formation software, which can distribute the magnetic charge per unit area, m, on the crack section area. Also the lift-off, measurement area and sensor interval, and magnetization direction can be considered in the preprocessor. Also, the postprocessor presents functions, such as the natural magnetic field distribution and ∂B/∂x, ∂B/∂y, as results. Also, the physical characteristics of the magnetic optical sensor and the Hall sensor are included in the postprocessor, and the magnetic field distribution can be changed to optical intensity and electrical signal distribution. The experiment results, which are obtained by using the magnetic camera on the crack, are compared with analysis results obtained by using the dipole model analysis software.

scholarly journals A Novel Breaking Strategy for Reduced Response Time of Electromagnetic Contactor by Reverse Voltage Application

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 789 ◽  
Author(s):  
Shuhua Fang ◽  
Yong Chen ◽  
Haimiao Ni ◽  
Heyun Lin ◽  
Xingang Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Response Time ◽  
Iron Core ◽  
Dramatic Reduction ◽  
Reverse Voltage ◽  
Excitation Coil ◽  
Voltage Application ◽  
Source Voltage ◽  
Drive Circuit ◽  
The Magnetic Field

This paper proposes a novel breaking strategy for dramatically shortening the response time of a single, stable electromagnetic contactor. A reverse voltage was applied across the excitation coil to increase the decay velocity of the magnetic field in the iron core, leading to a dramatic reduction of the electromagnetic force when the contactor initiated the breaking process. The applied time of the reverse voltage was determined by numerical computation of circuit, magnetic field, and forces. The polarity of source voltage was overturned by controlling switching devices in the bridge drive circuit. A co-simulation coupling magnetic field, machinery, and circuit was carried out using Maxwell and Circuit Editor software. Experimental results are reported to demonstrate the effectiveness of the proposed breaking strategy for shortening the response time of an electromagnetic contactor.

scholarly journals Development of Digital Scale Based on Fluxgate Sensor

2016 ◽  
Vol 1 ◽  
Author(s):  
Mitra Djamal
Keyword(s):  
Magnetic Field ◽  
Relative Error ◽  
Output Voltage ◽  
Absolute Error ◽  
Maximum Relative Error ◽  
Maximum Absolute Error ◽  
Sensor Development ◽  
Fluxgate Sensor ◽  
Excitation Coil ◽  
The Magnetic Field

<p>Fluxgate is a magnetic sensor which works by comparing the measurement magnetic field with the magnetic field reference. This research aims to develop digital scales using fluxgate sensor. The steps involved were sensor development, characterization, distance and mass calibration of the fabricated sensor. Here, a digital scale based on fluxgate sensor with oval vitrovac 6025Z type core, 360 windings of excitation coil and 240 windings of pick up coil was successfully fabricated. Characterization result shows that the sensor has 1669.2 mV/μT sensitivity and working area of about ± 1.9 μT, with maximum absolute error found out to be around 0.0573 μT with maximum relative error is 1.464 %. Calibrated sensor value obtained reveals that the sensor works from 15.86 until 27.00 mm in distance, utilizing equation of relationship between mass and output voltage  with the maximum relative error obtained as low as 1.49 %.</p>

scholarly journals Mobile robot with failure inspection system for ferromagnetic structures using magnetic memory method

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
N. J. Montes de Oca-Mora ◽  
R. M. Woo-Garcia ◽  
R. Juarez-Aguirre ◽  
A. L. Herrera-May ◽  
A. Sanchez-Vidal ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Mobile Robot ◽  
Oil And Gas ◽  
Magnetic Flux Density ◽  
Inspection System ◽  
Magnetic Memory ◽  
Destructive Testing ◽  
Reading Tests ◽  
High Level ◽  
The Magnetic Field

AbstractFlaws or cracks are one of the major failures in oil and gas pipeline networks. The early detection of these failures is very important for the safety of the industry, and this last requires of analysis for non-destructive testing (NDT), which is reliable, inexpensive and easy to implement. In this paper, we propose the development of an embedded prototype mounted on a mobile robot for the inspection of defects in ferromagnetic plates. This prototype has two embedded systems (control and data acquisition), which are based on a microcontroller of 8 and 32 bits, respectively. On the one hand, the first system for control has the logic to govern the sensors and motors that will allow to the robot moves with autonomous way during 45 min. While, the second system presents an algorithm for storing, processing and sending the data obtained from the sensors, being able to measure variations in the magnetic field in the order of 0.1 µT. Magnetic-field reading tests have been carried out on control ASTM A-27 ferromagnetic plates, obtaining experimental response in the 3 axes of the magnetic domains, which is very close to the expected results by the magnetic-flux density model that is calculated from the fields E and B derived from the equations of a Hertz dipole, and developed in the high-level Python programming language. The prototype proposed for NDT can detect geometric defects in the range of millimeters, producing changes in the density of the magnetic field in the order of thousands of µT.

scholarly journals Electromagnetic Acoustic Detection of Steel Plate Defects Based on High-Energy Pulse Excitation

2020 ◽  
Vol 10 (16) ◽  
pp. 5534
Author(s):  
Suzhen Liu ◽  
Ke Chai ◽  
Chuang Zhang ◽  
Liang Jin ◽  
Qingxin Yang
Keyword(s):  
Magnetic Field ◽  
Steel Plate ◽  
Maximum Amplitude ◽  
High Energy ◽  
Ferromagnetic Materials ◽  
Pulse Excitation ◽  
High Signal ◽  
Excitation Coil ◽  
Energy Pulse ◽  
Lift Off

The conventional electromagnetic ultrasonic transducers (EMATs) rely on the static magnetic field created by magnets. The magnet increases the size of the EMATs, and the strong magnetic force of the magnet attracts the detected steel and even ferromagnetic particles. It can cause mechanical damage to the transducer and the detected objects. A new high-energy acoustic excitation system, without a static bias magnetic is designed, which does not include any magnets. As the core of the system, the high-energy pulse excitation power supplies a transient high voltage to the excitation coil by the LC oscillation circuit. The maximum amplitude of current can reach 1700 A, which is much larger than the current in the conventional EMATs. Compared with the conventional EMATs, the intensity of the ultrasonic signal is greatly strengthened and the size of the EMAT is effectively reduced. Therefore, it can detect high-temperature steel plates at a higher lift-off distance. In this paper, the transduction mechanism of high-energy pulse electromagnetic acoustic on ferromagnetic materials was studied, and the high-energy pulse excitation coil used for the A0 mode Lamb wave was designed. The interaction rule of the magnetic field, the force field, and the acoustic field, was obtained. Then, the EMAT lift-off characteristic experiment of the high-energy pulse excitation was carried out, and the defect detection experiment was conducted on a cracked steel plate. The results show that the A0 mode Lamb waves have caused a high signal-to-noise ratio and can accurately locate the crack, which has a great advantage in detecting the microcrack defects of ferromagnetic materials.

scholarly journals Resonant frequency tracking mode on eddy current pulsed thermography non-destructive testing

2020 ◽  
Vol 378 (2182) ◽  
pp. 20190607
Author(s):  
Ling Miao ◽  
Bin Gao ◽  
Haoran Li ◽  
Guiyun Tian
Keyword(s):  
Resonant Frequency ◽  
Eddy Current ◽  
Crack Detection ◽  
Excitation Source ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Pulsed Thermography ◽  
Frequency Tracking ◽  
Excitation Coil ◽  
Non Destructive

Eddy current pulsed thermography (ECPT) has been widely used in the field of non-destructive testing due to its safety, non-contact detection, high spatial resolution and intuitive results. Inductive excitation source is an important component of ECPT and provides high-frequency alternating current to drive the excitation coil. However, a resonant frequency distortion phenomenon exists in the excitation source during the detection process, which seriously affects the output power of the excitation source and the sample detection effect. This paper presents a fast resonant frequency tracking loop for full bridge series resonant inverter which is used to search the resonance frequency in real time through direct digital synthesizer (DDS) and all-digital phase-locked loop. Theoretical analysis and simulation are presented to explain the working principle of the loop. Then, an experimental prototype is manufactured which serves as an excitation source for the ECPT experimental system. Compared with traditional excitation sources, the prototype does not need a water-cooled device and the tracking speed can be adjusted by modifying the parameters of DDS. Finally, experiments have been conducted on both artificial slot of 45# steel and natural cracks of rail and stainless steel to investigate the influence of resonant frequency tracking speed on the crack detection. The results revealed that reducing the resonant frequency tracking time can efficiently improve defect detectability and the manufactured prototype showed more application potential. This article is part of the theme issue ‘Advanced electromagnetic non-destructive evaluation and smart monitoring’.

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