scholarly journals Research on Internal Force Detection Method of Steel Bar in Elastic and Yielding Stage Based on Metal Magnetic Memory

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1167 ◽  
Author(s):  
Caoyuan Pang ◽  
Jianting Zhou ◽  
Ruiqiang Zhao ◽  
Hu Ma ◽  
Yi Zhou
Keyword(s):  
Tensile Force ◽  
Extreme Points ◽  
Internal Force ◽  
Axial Position ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Destructive Testing ◽  
Force Detection ◽  
Steel Bar ◽  
Tensile Forces

Based on the metal magnetic memory effect, this paper proposed a new non-destructive testing method for the internal tensile force detection of steel bars by analyzing the self-magnetic flux leakage (SMFL) signals. The variation of the SMFL signal of the steel bar with the tensile force indicates that the curve of the SMFL signal has a significant extreme point when the tensile force reaches about 65% of the yield tension, of which the first derivative curve has extreme points in the elastic and yielding stages, respectively. To study the variation of SMFL signal with the axial position of the steel bar under different tensile forces, a parameter reflecting the fluctuation of the SMFL signal along the steel bar is proposed. The linear relationship between this parameter and the tensile force can be used to quantitatively calculate the tensile force of steel bar. The method in this paper provides significant application prospects for the internal force detection of steel bar in the actual engineering.

scholarly journals A New Method for Internal Force Detection of Steel Bars Covered by Concrete Based on the Metal Magnetic Memory Effect

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 661 ◽  
Author(s):  
Caoyuan Pang ◽  
Jianting Zhou ◽  
Qingyuan Zhao ◽  
Ruiqiang Zhao ◽  
Zhuo Chen ◽  
...  
Keyword(s):  
Memory Effect ◽  
Internal Force ◽  
New Method ◽  
Detection Methods ◽  
Axial Position ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Force Detection ◽  
Steel Bar ◽  
Steel Bars

In this paper, the specimens of steel bars covered by concrete (SBCC) are taken as research objects, and a new method for steel bar internal force detection based on the metal magnetic memory effect is proposed. The variation law of the self-magnetic flux leakage (SMFL) signals on the surfaces of SBCC specimens with loading tension and the variation of the SMFL signals along the axial positions of specimens under different tensile forces are studied. The results show that when the loading tension is about 90% of the yield tension, the tangential component of the SMFL signal has a maximum extreme point. The distribution of the SMFL signals along the axial position shows a smooth curve, where the values at both ends are small while the intermediate values are large. This paper also proposes the use of the “area ratio deviation parameter” to quantitatively calculate the internal forces of the steel bars. This parameter shows a significant linear relationship with the loading tension during the strengthening stage of the specimens. This method can supplement the existing steel bar stress detection methods and has prospective research value.

A Review of the Metal Magnetic Memory Technique

2016 ◽  
Author(s):  
Sheng Bao ◽  
Meili Fu ◽  
Shengnan Hu ◽  
Yibin Gu ◽  
Huangjie Lou
Keyword(s):  
Experimental Investigations ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Non Destructive Testing ◽  
Early Failure ◽  
Destructive Testing ◽  
Damage State ◽  
Recent Developments ◽  
As Stress ◽  
Non Destructive

Metal magnetic memory (MMM) is a newly developed non-destructive testing (NDT) technique. It has potentials to detect early failure, such as stress concentration, micro-crack and fatigue damage of ferromagnetic components. This paper outlines the recent developments of the mechanism studies on the MMM technique. Several advances in experimental investigations on the MMM technique are also summarized, e.g. the factors which can influence the detection signals, the criteria for judging the damage state and the magnetic parameters which can be used to assess the testing results. Finally, some future development trends about this technique are suggested.

Quantitative research of defects for pipelines based on metal magnetic memory testing

2020 ◽  
Vol 62 (5) ◽  
pp. 292-299 ◽  
Author(s):  
Wei Zhou ◽  
Jianchun Fan ◽  
Xiangyuan Liu ◽  
Shujie Liu
Keyword(s):  
Quantitative Research ◽  
Three Dimensional ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Magnetic Signal ◽  
Destructive Testing ◽  
Gas Industry ◽  
Defect Profile ◽  
Comparison Results ◽  
Dimensional Distribution

Pipelines are widely used in the oil & gas industry but defects seriously affect their safe operation. Therefore, it is necessary to perform non-destructive testing (NDT) to quantify the defects. In this study, a magnetic dipole model was established to characterise the defects and magnetic flux leakage (MFL) of defects was simulated using the finite element method (FEM) to reveal the spatial distribution of the magnetic vector. Magnetic signals were measured using a tunnel magnetoresistance (TMR) sensor array and the results showed that defects with different sizes could be quantified using the metal magnetic memory (MMM) method. Three-dimensional distribution of the magnetic signal and its gradient reflected the defect profile well and the gradient of the magnetic signal was found to reduce the effect of non-uniform magnetisation. Furthermore, experimental results were verified by comparison with the simulation results and the comparison results showed a consistent variation trend. Quantitative analysis was conducted and the characteristic parameters of the gradients could be used to quantify the defects.

Study on Physical Mechanism of Metal Magnetic Memory Technique

2010 ◽  
Vol 34-35 ◽  
pp. 841-844 ◽  
Author(s):  
Da Bo Wu ◽  
Min Qiang Xu ◽  
Jian Wei Li
Keyword(s):  
Memory Effect ◽  
Physical Mechanism ◽  
Stress Measurement ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Destructive Testing ◽  
Engineering Structures ◽  
Testing Metal ◽  
Induced Magnetic Anisotropy ◽  
Non Destructive

The evaluation of stresses in engineering structures to provide early indications of stress status is a fast growing area in non-destructive testing. Metal magnetic memory technique is the magnetic stress measurement technique for ferromagnetic materials using passive magnetic fields to monitor changes in the magnetic properties of materials. This paper studied the physical formation process of metal magnetic memory effect. This paper studied the physical mechanism between stress and magnetic field in metal magnetic memory effect, through the influence of stress-induced magnetic anisotropy on magnetization process of ferromagnetic crystal.

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