Stress Concentration Positions Determination of Ferromagnetic Material Based on Magnetic Test Method

2009 ◽  
Vol 417-418 ◽  
pp. 865-868
Author(s):  
Feng Yun Yu ◽  
Jing Chong Zhang
Keyword(s):  
Magnetic Field ◽  
Stress Concentration ◽  
Spontaneous Magnetization ◽  
Tensile Load ◽  
Test Point ◽  
Test Method ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Magnetic Intensity ◽  
The Magnetic Field

The magnetic field of ferromagnetic components under service load and geomagnetic field increases is induced by the residual magnetic induction and spontaneous magnetization. The stress concentration positions can be determination by detecting the magnetic field and the fracture can be avoided. The magnetic intensities of the demagnetized samples are tested by metal magnetic memory test method. By tensile test, the relationship between the magnetic memory signals and tensile load is studied, and the metal magnetic memory characteristics of the demagnetized samples under condition that the load keeps a fixed value are obtained. The test result indicates that the magnetic intensities of the samples change greatly after demagnetized; the change of the magnetic intensity of each test point are much different with different tensile displacement; in the later period of hardening phase and necking phase, the magnetic intensity about the side of the stress concentration positions increases along with the increasing of tensile displacement, however that of the other side decreases, that is the gradient of Fracture position increases obviously. Basing on this result by testing the parts of components emphatically where the fatigue failure and breakdown appear easily, the abrupt accident can be avoided.

On Damage Evaluation Method of the Ferromagnetic Material Based on Weak Magnetic Field Detection Technology

2006 ◽  
Vol 324-325 ◽  
pp. 331-334 ◽  
Author(s):  
Feng Yun Yu ◽  
Chuan Xu Zhang ◽  
Miao Wu
Keyword(s):  
Magnetic Field ◽  
Standard Deviation ◽  
Evaluation Method ◽  
Spontaneous Magnetization ◽  
Tensile Load ◽  
Ferromagnetic Material ◽  
Magnetic Intensity ◽  
Damage Level ◽  
Detection Technology ◽  
The Magnetic Field

The increase of magnetic field of ferromagnetic components under service load and geomagnetic field is induced by the residual magnetic induction and spontaneous magnetization. The stress concentration positions can be found by detecting the magnetic field and the fracture can be avoided. The variation of the residual magnetic intensity of bearing carriers under different damage conditions is studied in this paper; the statistical characteristic of the residual magnetic intensity of the specimens in different residual deformations is got, and a concept of residual magnetic intensity standard deviation is put forward with a lot of experiments and in-depth theoretic analysis. The results indicate that the curves of residual magnetic intensity standard deviation appear obvious turning points when the specimens reach the yield point in different original magnetic field conditions, and that the function between residual magnetic intensities standard deviation, tensile load and strain is established. Therefore, the plastic deformation can be judged by the variation of the magnetic field in their service process, and the damage level can be evaluated consequently, which gives a new reliable method to estimate the deformation of ferromagnetic material.

The State-of-the-Art Surveys for Application of Metal Magnetic Memory Testing in Remanufacturing

2011 ◽  
Vol 301-303 ◽  
pp. 366-372 ◽  
Author(s):  
Yuan Liang Zhang ◽  
Di Zhou ◽  
Peng Sen Jiang ◽  
Hong Chao Zhang
Keyword(s):  
Magnetic Field ◽  
Stress Concentration ◽  
Residual Life ◽  
Fatigue Cracks ◽  
Research Work ◽  
Creep Damage ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Comprehensive Survey ◽  
Chinese Scholars

Metal magnetic memory（MMM） testing has been used in the residual life prediction of remanufacturing cores. The MMM testing is one of the most promising nondestructive testing methods for achieving early diagnosis on micro defects of remanufacturing cores. This method can not only detect the traditional macro-cracks, but also identify the micro-damage caused by stress concentration. The principle of MMM testing works in the conditions that without requiring of the external exciting magnetic field, the magnetic field distribution of the inspection surface is scanned and measured by means of magnetic mutation signals to find the possible existence of stress concentration and location of micro-cracks. This paper presents a state-of-art survey about MMM testing mechanism and application of MMM method in Russia, Britain, China and the other countries. It includes the applications of this method in power station turbine blade damage detection by Russia scholars, evaluating the gear creep damage by Polish scholars and detecting the stress concentration districts of the train wheels damaged parts by Chinese scholars. The paper also reports that Chinese scholars developed methods of using MMM testing to characterize initiating and growing of fatigue cracks, and applied this method for prediction of residual life of remanufacturing cores. Based on the comprehensive survey, this paper points out further trends of the research work in the area. The paper also points out that microscopic physical mechanism of the MMM phenomenon and application of MMM testing in defining the manufacturability of remanufacturing cores should be further studied. Introduction

Correlation Between Stress Concentration Degree and Residual Magnetic Field

2016 ◽  
Author(s):  
Sheng Bao ◽  
Ashri Mustapha ◽  
Huangjie Lou
Keyword(s):  
Magnetic Field ◽  
Stress Concentration ◽  
Tensile Tests ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Residual Magnetic Field ◽  
Concentration Degree ◽  
Qualitative Relationship ◽  
Ferromagnetic Steels

In this research, the correlation between the stress concentration degree and the residual magnetic field (RMF) of ferromagnetic steels is investigated. Tensile tests were carried out to measure the RMF signals on the surface of steel specimens with different stress concentration degrees. The effectivity of the metal magnetic memory (MMM) technique in defective specimens was investigated in comparison with a non-defective specimen. Analysis of the qualitative relationship between the stress concentration degree and the RMF components was subsequently performed on two types of defective specimens. The qualitative correlation between the planar distributions of the RMF components and the stress concentration degree was further studied. It was validated that both the RMF signal and its planar distribution are effective in characterizing the stress concentration degree. The results obtained in this research will be a complement to the MMM technique.

Numerical Studies to Signal Characteristics with the Metal Magnetic Memory-Effect Based of Cast Iron

2014 ◽  
Vol 633-634 ◽  
pp. 277-283 ◽  
Author(s):  
Yi Bo Peng ◽  
Shang Feng Pan ◽  
Chao Lu
Keyword(s):  
Cast Iron ◽  
Stress Concentration ◽  
Early Stage ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Magnetic Signal ◽  
Numerical Studies ◽  
Signal Characteristics ◽  
The Magnetic Field ◽  
Early Damage

HT300 (Cast Iron) is widely used in heavy machines, and the metal magnetic memory (MMM) technique can is used to evaluate early damage of the following metal while calculating the stress concentration. An experimental investigation of the effect of stress on permeability of HT300 has been undertaken on cast iron. The result showed that the stress can alter the permeability of the material which will amplify the magnetic field of the specimen. Further, simulation was used to evaluate the characteristics of magnetic signal under different conditions. The present work indicate that the MMM can detect stress concentration and early stage of damage effectively.

Monitoring the Petrol Engine Oil Viscosity: Investigation of the Capability of the Metal Magnetic Memory Technology

2014 ◽  
Vol 663 ◽  
pp. 453-458
Author(s):  
Othman Inayatullah ◽  
Wang Siow Chin ◽  
Nordin Jamaludin ◽  
Shahrum Abdullah ◽  
Azli Ariffin
Keyword(s):  
Magnetic Field ◽  
Petrol Engine ◽  
Engine Oil ◽  
Field Energy ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Oil Viscosity ◽  
Maintenance Schedule ◽  
Magnetic Field Energy ◽  
The Magnetic Field

An engine lubrication system is one of the main factors which influence engine life span, and it can be easily determined based on the viscosity of the engine oil. The current and common technology for monitoring and the determination of the engine oil viscosity using the oil analysis method is found to be uneconomical and ineffective. On the same vein, this paper presents an investigation of the capability of the Metal Magnetic Memory (MMM) technology in the processes of monitoring and detecting the variation of petrol engine lubricant viscosity via in-situ operation. A few investigations were conducted on a Robin Engine 126 cc EX 13D single cylinder of four strokes with water cooling. One multi-grade engine lubricant oil condition has been put to the test; namely, SAE 15W-40. During the investigation of the petrol engine oil viscosity, the magnetic field signal is captured when the engine oil in-service age is 0 km (fresh oil), 250 km, 500 km, 750 km and 1,000 km, with the crankshaft rotational speed of 2500 rpm at three different locations such as at the Bottom Dead Centre (BDC), oil sump A (engine oil inlet), and oil sump B. The lubrication condition in the petrol engine is successfully monitored based on the magnetic field signatures generated by the interaction between the piston surface and the layer of the lubricant during the time when the engine was in operation. The generated MMM signatures were captured using a type 2 scanning device with two ferroprobe sensors and a length measuring sensor and recorded by the TSC-3M-12 type device. The waveform signatures captured were displayed as length domain signal and then were analysed using the MATLAB software to determine the magnetic field energy (EH). In addition, the real viscosity value at room temperature was determined using the Haake Viscotester 6 L, each time after the magnetic field signal was captured. The results of these studies have shown that the magnetic field energy (EH) is inversely proportional to engine oil viscosity. Finally, the MMM technology can be utilised in promoting economic development and effective planning of the maintenance schedule of the petrol engine oil.

Experimental Study of Magnetic Field Variation Induced in Ferromagnetic Materials

2013 ◽  
Vol 312 ◽  
pp. 402-405
Author(s):  
Yang Yong ◽  
Dong Sun ◽  
Jie Ji
Keyword(s):  
Magnetic Field ◽  
Plastic Region ◽  
Steel Specimen ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Magnetic Memory ◽  
Field Variation ◽  
Magnetic Field Variation ◽  
Metal Magnetic Memory ◽  
Stress Increase

The fatigue tests on 15CrMo steel specimen were carried out and the metal magnetic memory (MMM) signals were detected. The experiment shows that the magnetic signals of specimen contain the information of stress distribution in the material inside. Furthermore, the experimental results show that the magnetic signals increase initial while then decrease slightly with the stress increase from 0kN to 200kN. Though analysis the MMM signals induced by different tensile stress within the plastic region of the specimen, a simple model was derived. The experimental results are consistent with the calculated results based on the Jiles-Atherton model.

scholarly journals Investigation of the Impact of Load on the Magnetic Field Strength of the Crane by the Magnetic Metal Memory Technique

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5559
Author(s):  
Agnieszka Koson-Schab ◽  
Janusz Szpytko
Keyword(s):  
Residual Magnetization ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Magnetic Metal ◽  
Structural Inspection ◽  
The Impact ◽  
Non Destructive ◽  
The Magnetic Field ◽  
Flux Leakage ◽  
Destructive Methods

The paper deals with the problem of applicability of the metal magnetic memory (MMM) technique in the crane structural inspection and monitoring. The MMM method does not require the external magnetization of a structure that results in reduction of downtime of maintenance operations. Measurement of the intensity of the self-magnetic leakage signal can be an alternative to other non-destructive methods used for inspection of a large crane’s structure and equipment. However, the complexity of the residual magnetization effect in the MMM technique is the problem with its application. Thus, the magnetic flux leakage behavior on the crane girder surface under different measurements and the crane’s load conditions is analyzed based on the results obtained during experiments carried out on the overhead traveling crane.

Calculation of Magnetic Field of the 168 kA Aluminum Reduction Cell with ANSYS

2012 ◽  
Vol 524-527 ◽  
pp. 1993-1996
Author(s):  
Yan Li Jiang ◽  
Liang Yu ◽  
Nai Xiang Feng
Keyword(s):  
Magnetic Field ◽  
Aluminum Reduction Cell ◽  
Short Axis ◽  
Magnetic Line ◽  
Magnetic Intensity ◽  
Aluminum Reduction ◽  
Reduction Cell ◽  
Project Analysis ◽  
Intensity Vector ◽  
The Magnetic Field

The magnetic field of the 168 kA aluminum reduction cell was calculated with the software ANSYS in our study. The calculated results showed that the magnetic line of the aluminum and electrolyte in cell formed a clockwise swirl. The X and Z magnetic intensity of aluminum was similar with the antisymmetric distribution and the magnetic intensity vector of aluminum reduced along the -Z axis. The X, Y and Z magnetic intensity in the electrolyte under the anode bottom was similar with the antisymmetric distribution along short axis (Y axis), long axis (X axis) and short axis (Y axis), respectively. The magnetic intensity vector of electrolyte in the gap of the anode was higher than that under the anode bottom. The X and Z magnetic intensity in the interface of melt was also similar with the antisymmetric distribution. The numerical simulations with ANSYS have the important references for project analysis and diagnose.

AN ELECTROMAGNETIC INTERPRETATION PROBLEM IN GEOPHYSICS

Geophysics ◽  
1951 ◽  
Vol 16 (3) ◽  
pp. 431-449 ◽  
Author(s):  
L. B. Slichter
Keyword(s):  
Magnetic Field ◽  
Electrical Properties ◽  
Magnetic Field Intensity ◽  
Vertical Component ◽  
Single Frequency ◽  
Magnetic Intensity ◽  
Conductivity Function ◽  
The Magnetic Field ◽  
Surface Observations ◽  
Interpretation Problem

An interpretation problem in electromagnetic prospecting is discussed. A flat earth in which the three electrical properties of material vary only with depth is subjected to an alternating inducing field produced by a dipole above the surface with axis perpendicular to the surface. Observations of the horizontal or of the vertical component of the magnetic intensity at the ground’s surface are supposed to be available at all distances. From these observations solutions for the three unknown functions are developed. When the magnetic permeability is variable, the solutions for the permeability and dielectric functions require observations at two different frequencies. The conductivity function may be found from observations at a single frequency. It is shown that the horizontal and vertical components of the magnetic field intensity are mutually dependent in the region above the ground’s surface; and formulae independent of the ground’s characteristics are deduced for expressing [Formula: see text] in terms of [Formula: see text], and vice‐versa. Here [Formula: see text] denotes a plane coincident with or above and parallel to, the earth’s surface.

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