Research on Correlation of Electromagnetic and Induced Charge of Coal-rock in Deformation and Fracture

Rockburst Prediction Based on Electromagnetic Radiation Technology and its Application

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1010-1012.1564 ◽

2014 ◽

Vol 1010-1012 ◽

pp. 1564-1567 ◽

Cited By ~ 1

Author(s):

Chao Wang ◽

Wei Peng

Keyword(s):

Electromagnetic Radiation ◽

Rock Burst ◽

Monitoring Method ◽

Radiation Technology ◽

Working Face ◽

Deformation And Fracture ◽

Short Period ◽

Coal Rock ◽

Relationship Of ◽

The Relationship

Rock bursts are serious threats to safety and production in coalmines, which are becoming more serious with the increase in mining intensity and depth. Electromagnetic radiation (EMR) always occurs along with coal rock deformation and fracture. EMR monitoring technique, the method using the short period changes of EMR signals before rock burst, has been widely applied to monitor and predict rock burst. This paper mainly studied the relationship of EMR generated by coal rock mass to applied loads and monitored the working face and roadways of coalmine by monitoring instrument, the results show that the EMR monitoring method has excellent performance in predicting rock burst.

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Multifield Coupling Mechanism of Unloading Deformation and Fracture of Composite Coal-Rock

Shock and Vibration ◽

10.1155/2021/2450330 ◽

2021 ◽

Vol 2021 ◽

pp. 1-16

Author(s):

Zhen Yang ◽

Yan Li ◽

Xin Li ◽

Jiayu Zhuang ◽

Hao Li ◽

...

Keyword(s):

Electromagnetic Field ◽

Electromagnetic Radiation ◽

Field Variation ◽

Rock Body ◽

Deformation And Fracture ◽

Initial Stage ◽

Multiphysics Coupling ◽

Coal Rock ◽

Loading And Unloading ◽

Simulation Results

The deformation and fracture evolution of coal and rock under unloading are prone to sudden instability or dynamic damage. To solve the problem, this paper combines interdisciplinary theories such as damage mechanics and electromagnetic field theory. The mathematical model of multiphysics coupling during loading and unloading of composite coal-rock is deduced. In addition, numerical simulations along with experimental verification are carried out to study multi-physical field variation and coupling mechanisms. The composite coal-rock deforms and ruptures under unloading, and the brittle failure of the rock body becomes more sudden when the confining pressure is unloaded. Macroscopically, many microcracks are generated and expanded during the loading and unloading of composite coal-rock. Microscopically, the internal old molecular chains are broken to form new molecular chains by the force. Simulation results show that, during the loading and unloading process, the three physical fields of the composite coal-rock all change regularly. During the unloading of coal and rock, there is a transition period in which the temperature increases sharply and reaches the maximum. Then, the temperature decreases due to the gradual decrease of its bearing capacity. Besides, the electromagnetic field is strongest on the surface of the coal body, and its propagation in the air decays exponentially. There are small fluctuations that appear at the junction of the coal body and the air. The experimental results show that the internal infrared radiation temperature of the composite coal-rock decreases during the initial stage of loading and unloading due to the discharge of internal gas. In the first stage of “loading and unloading,” it increases with the increase in stress, and the temperature suddenly increases in a short time after unloading. The electromagnetic radiation fluctuates in small amplitudes at the initial stage. When the stress is about to reach the peak, the electromagnetic radiation intensity increases and reaches the peak suddenly. Then, the coal-rock ruptures, the stress decreases, and the electromagnetic radiation weakens. The experiment and simulation results are consistent. The multiphysics coupling model is used to study the characteristics of coal and rock unloading under complex conditions, providing a theoretical basis and new method for the prediction and forecast of coal and rock mining dynamic disasters.

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Environmental cell studies of deformation and fracture

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100175715 ◽

1990 ◽

Vol 48 (4) ◽

pp. 516-517

Author(s):

H. K. Birnbaum ◽

I. M. Robertson

Keyword(s):

National Laboratory ◽

Argonne National Laboratory ◽

Damage Threshold ◽

Chromatic Aberration ◽

Good Choice ◽

Point Of View ◽

Deformation And Fracture ◽

Environmental Cell ◽

Gas Molecules ◽

The University

Studies of the effects of hydrogen environments on the deformation and fracture of fcc, bcc and hep metals and alloys have been carried out in a TEM environmental cell. The initial experiments were performed in the environmental cell of the HVEM facility at Argonne National Laboratory. More recently, a dedicated environmental cell facility has been constructed at the University of Illinois using a JEOL 4000EX and has been used for these studies. In the present paper we will describe the general design features of the JEOL environmental cell and some of the observations we have made on hydrogen effects on deformation and fracture.The JEOL environmental cell is designed to operate at 400 keV and below; in part because of the available accelerating voltage of the microscope and in part because the damage threshold of most materials is below 400 keV. The gas pressure at which chromatic aberration due to electron scattering from the gas molecules becomes excessive does not increase rapidly with with accelerating voltage making 400 keV a good choice from that point of view as well. A series of apertures were placed above and below the cell to control the pressures in various parts of the column.

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Deformation and fracture behavior of an Al-Li-Cu-Mg-Zr alloy 8090

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178008 ◽

1990 ◽

Vol 48 (4) ◽

pp. 974-975

Author(s):

D.M. Jiang ◽

B.D. Hong

Keyword(s):

High Strength ◽

Deformation And Fracture ◽

Fracture Behaviors ◽

Aluminum Lithium ◽

Carbon Fiber Reinforced Composites ◽

Peak Aged ◽

Aluminum Lithium Alloys ◽

High Strength Aluminum Alloys ◽

Lithium Alloys ◽

Zr Alloy

Aluminum-lithium alloys have been recently got strong interests especially in the aircraft industry. Compared to conventional high strength aluminum alloys of the 2000 or 7000 series it is anticipated that these alloys offer a 10% increase in the stiffness and a 10% decrease in density, thus making them rather competitive to new up-coming non-metallic materials like carbon fiber reinforced composites.The object of the present paper is to evaluate the inluence of various microstructural features on the monotonic and cyclic deformation and fracture behaviors of Al-Li based alloy. The material used was 8090 alloy. After solution treated and waster quenched, the alloy was underaged (190°Clh), peak-aged (190°C24h) and overaged (150°C4h+230°C16h). The alloy in different aging condition was tensile and fatigue tested, the resultant fractures were observed in SEM. The deformation behavior was studied in TEM.

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