Experimental Study of the Influencing Factors of Elevator Cable Magnetic Flux Leakage Detection Signal

2013 ◽  
Vol 711 ◽  
pp. 327-332
Author(s):  
Yi Su ◽  
Zhen Zhang ◽  
Tao Zhang ◽  
Ming Li Yang ◽  
Mei Lin ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Magnetic Flux Leakage ◽  
Probe Design ◽  
Détection Signal ◽  
Detection Mechanism ◽  
Fracture Width ◽  
Lift Off ◽  
Elevator Cable ◽  
Flux Leakage ◽  
Detection Signal

The detection mechanism of Magnetic Flux Leakage (MFL) Method of elevator cable is proposed. Using Gauss-Mercury method to analyze the influence of different factors that lift-off value, fracture width, broken wires number and diameter and depth all that based on the collecting experimental system of MFL signals. The method can be used to optimize the detection probe design and detection signal processing.

scholarly journals A Lift-Off-Tolerant Magnetic Flux Leakage Testing Method for Drill Pipes at Wellhead

Sensors ◽  
2017 ◽  
Vol 17 (12) ◽  
pp. 201 ◽  
Author(s):  
Jianbo Wu ◽  
Hui Fang ◽  
Long Li ◽  
Jie Wang ◽  
Xiaoming Huang ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Magnetic Flux Leakage ◽  
Testing Method ◽  
Drill Pipes ◽  
Lift Off ◽  
Flux Leakage ◽  
Magnetic Flux Leakage Testing

scholarly journals A Method for Detecting Surface Defects in Railhead by Magnetic Flux Leakage

2021 ◽  
Vol 11 (20) ◽  
pp. 9489
Author(s):  
Yinliang Jia ◽  
Shicheng Zhang ◽  
Ping Wang ◽  
Kailun Ji
Keyword(s):  
Magnetic Flux ◽  
Surface Defects ◽  
Rapid Development ◽  
Magnetic Flux Leakage ◽  
Detection Accuracy ◽  
Physical Experiments ◽  
Detection Technology ◽  
Element Simulation ◽  
Lift Off ◽  
Flux Leakage

With the rapid development of the world’s railways, rail is vital to ensure the safety of rail transit. This article focuses on the magnetic flux leakage (MFL) non-destructive detection technology of the surface defects in railhead. A Multi-sensors method is proposed. The main sensor and four auxiliary sensors are arranged in the detection direction. Firstly, the root mean square (RMS) of the x-component of the main sensor signal is calculated. In the data more significant than the threshold, the defects are determined by the relative values of the sensors signal. The optimal distances among these sensors are calculated to the size of a defect and the lift-off. From the finite element simulation and physical experiments, it is shown that this method can effectively suppress vibration interference and improve the detection accuracy of defects.

A novel magnetic flux leakage method based on the ferromagnetic lift-off layer with through groove

2021 ◽  
Vol 332 ◽  
pp. 113091
Author(s):  
Jian Tang ◽  
Rongbiao Wang ◽  
Bocheng Liu ◽  
Yihua Kang
Keyword(s):  
Magnetic Flux ◽  
Magnetic Flux Leakage ◽  
Lift Off ◽  
Flux Leakage

Optimising sensor pitch for magnetic flux leakage imaging systems

2021 ◽  
Vol 63 (7) ◽  
pp. 416-421
Author(s):  
R Murshudov ◽  
J M Watson ◽  
C W Liang ◽  
J Sexton ◽  
M Missous
Keyword(s):  
Magnetic Flux ◽  
Imaging System ◽  
Sensor Arrays ◽  
Magnetic Sensors ◽  
Magnetic Flux Leakage ◽  
Step Size ◽  
Optimal Spacing ◽  
Minimum Number ◽  
Lift Off ◽  
Flux Leakage

Sensor arrays can significantly increase the speed at which inspections and subsequent imaging of flaws is performed[1]. This work focuses on developing a software approach for optimising the spacing between quantum well Hall-effect (QWHE) magnetic sensors used for magnetic flux leakage (MFL) imaging, where this approach could be adapted for any non-destructive evaluation (NDE) technique in which imaging is obtained. A ground mild steel weld sample containing two surface-breaking flaws prepared by Sonaspection was scanned using an XYZ MFL imaging system developed at the University of Manchester[2,3,13,14]. The scan was taken with an autonomously controlled lift-off height of 0.75 mm, with an x-y measurement step of 100 μm and an applied magnetic field of 30 mT root mean square (RMS) at a frequency of 400 Hz. This data (ie magnetic image) was then processed to simulate different measurement step sizes, to determine any relationship between step size and flaw detectability (flaw signal to weld background response). This work effectively simulates different sensor pitches (separation between sensors) of integrated QWHE sensor arrays from 100 μm to 5 mm, with the goal of determining both the minimum number of sensors required in the array and the optimal spacing to maximise scan speeds and help determine optimum inspection parameters to develop the technology of low-power MFL imaging. This optimisation process could be applied to any NDE imaging system (electromagnetic or other) currently used, with results dependent on the inspection parameters.

scholarly journals An Analytical Model for Prediction of Magnetic Flux Leakage from Surface Defects in Ferromagnetic Tubes

2016 ◽  
Vol 16 (1) ◽  
pp. 8-13 ◽  
Author(s):  
V. Suresh ◽  
A. Abudhahir
Keyword(s):  
Magnetic Flux ◽  
Analytical Model ◽  
Surface Defects ◽  
Experimental Results ◽  
Magnetic Flux Leakage ◽  
Analytical Expression ◽  
Cylindrical Holes ◽  
Lift Off ◽  
Flux Leakage ◽  
Good Agreement

Abstract In this paper, an analytical model is proposed to predict magnetic flux leakage (MFL) signals from the surface defects in ferromagnetic tubes. The analytical expression consists of elliptic integrals of first kind based on the magnetic dipole model. The radial (Bz) component of leakage fields is computed from the cylindrical holes in ferromagnetic tubes. The effectiveness of the model has been studied by analyzing MFL signals as a function of the defect parameters and lift-off. The model predicted results are verified with experimental results and a good agreement is observed between the analytical and the experimental results. This analytical expression could be used for quick prediction of MFL signals and also input data for defect reconstructions in inverse MFL problem.

Magnetic Flux Leakage Sensing: Current Practices and Mathematical Analysis

2007 ◽  
Author(s):  
Sushant M. Dutta ◽  
Fathi H. Ghorbel
Keyword(s):  
Magnetic Flux ◽  
Magnetic Flux Leakage ◽  
Defect Characterization ◽  
3 Dimensional ◽  
Hall Effect Sensor ◽  
Leakage Field ◽  
Lift Off ◽  
Flux Leakage ◽  
Insight Into ◽  
Current Practices

In this paper, we analyze magnetic flux leakage (MFL) sensing for the nondestructive evaluation (NDE) of ferromagnetic specimens. Understanding the processes involved in the creation of magnetic flux leakage fields and their measurement is critical to robotic inspection applications. In particular, robotic inspection of energy pipelines uses mobile robots to magnetize sections of the pipe and to measure the MFL signal to detect defects. We study current practices and motivate the need for improvements. To facilitate the analysis, we develop an analytical model to represent the 3-dimensional magnetic flux leakage field due to a surface-breaking defect in the specimen. The model is derived from first principles using the concept of dipole magnetic charge, and uses surface integrals to represent the MFL field as measured by a Hall-effect sensor. Simulations are performed which generate novel results, apart from reproducing experimental results from the literature. The mathematical tractability of the model is exploited to analyze its properties, such as scale–invariance, influence of lift-off, and the tangential MFL component. These properties give new insight into MFL sensing, interpretation, and defect characterization.

scholarly journals Defect Width Assessment Based on the Near-Field Magnetic Flux Leakage Method

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5424
Author(s):  
Erlong Li ◽  
Yiming Chen ◽  
Xiaotian Chen ◽  
Jianbo Wu
Keyword(s):  
Magnetic Flux ◽  
Near Field ◽  
Experimental Studies ◽  
Magnetic Flux Leakage ◽  
Geometrical Parameters ◽  
Destructive Testing ◽  
Lift Off ◽  
Two Peaks ◽  
Non Destructive ◽  
Flux Leakage

Magnetic flux leakage (MFL) testing has been widely used as a non-destructive testing method for various materials. However, it is difficult to separate the influences of the defect geometrical parameters such as depth, width, and length on the received leakage signals. In this paper, a “near-field” MFL method is proposed to quantify defect widths. Both the finite element modelling (FEM) and experimental studies are carried out to investigate the performance of the proposed method. It is found that that the distance between two peaks of the “near-field” MFL is strongly related to the defect width and lift-off value, whereas it is slightly affected by the defect depth. Based on this phenomenon, a defect width assessment relying on the “near-field” MFL method is proposed. Results show that relative judging errors are less than 5%. In addition, the analytical expression of the “near-field” MFL is also developed.

Sign in / Sign up

Export Citation Format

Share Document