scholarly journals Experimental Investigation on the Energy Storage Characteristics of Red Sandstone in Triaxial Compression Tests with Constant Confining Pressure

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Liuliu Li ◽  
Fengqiang Gong
Keyword(s):  
Energy Density ◽  
Elastic Energy ◽  
Quadratic Function ◽  
Input Energy ◽  
Compression Tests ◽  
Red Sandstone ◽  
Elastic Energy Density ◽  
Deep Rock ◽  
Confining Pressures ◽  
Input Energy Density

The elastic energy stored in deep rock in three-dimensional stress environment is the energy source of rockburst. To investigate the energy storage characteristics of deep rock under different confining pressures, a series of triaxial single-cyclic loading-unloading compression tests were conducted on red sandstone specimens under eight confining pressures. The input energy density, elastic energy density, and dissipative energy density of the specimen in axial, circumferential, and total directions can be obtained by the area diagram integration method. The results show that the input energy density in the axial direction accounts for the largest logarithmic proportion of the total input energy density, and the relationship between all energy density parameters and unloading level can be described by quadratic function. In the axial direction, there is a linear function relationship among elastic energy density, dissipative energy density, and input energy density. In the circumferential direction, there is a quadratic function relationship among elastic energy density, dissipative energy density, and input energy density. For the total energy density parameters of the rock specimen, the relationship among elastic energy density, dissipative energy density, and input energy density conforms to the quadratic function. According to the above correlation function, the elastic energy stored in deep rock under different confining pressures can be accurately obtained, which provides a foundation for studying the mechanism of rockburst under three-dimensional unloading from the energy perspective.

scholarly journals Energy Evolution Characteristics and Distribution Laws of Rock Materials under Triaxial Cyclic Loading and Unloading Compression

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Mingwei Zhang ◽  
Qingbin Meng ◽  
Shengdong Liu
Keyword(s):  
Cyclic Loading ◽  
Energy Density ◽  
Elastic Energy ◽  
Confining Pressure ◽  
Dissipated Energy ◽  
Energy Evolution ◽  
Elastic Energy Density ◽  
Evolution Characteristics ◽  
Storage Limit ◽  
Confining Pressures

To explore the influence of confining pressure on the energy evolution characteristics of loaded rocks, triaxial cyclic loading-unloading experiments on sandstones were carried out under 6 kinds of confining pressures using the axial loading and circumferential deforming control modes. Total energy density, elastic energy density, and dissipated energy density absorbed by rock specimens under different confining pressures were obtained. The confining pressure effect of the evolution process and distribution law in energy accumulation and dissipation was analyzed. Energy conversion mechanism from rock deformation to failure was revealed, and energy conversion equations in different stress-strain stages were established. The method of representing the rock energy accumulation, dissipation, and release behaviors by energy storage limit density, maximum dissipated energy density, and residual elastic energy density was established. The rock showed that, with the increase of confining pressure, the characteristic energy density of rock increased in the power exponent form, and the energy storage limit density increased faster than the maximum dissipated energy density. The greater the confining pressure was, the greater the proportion of elastic energy before peak was. It is indicated that the confining pressure increased the energy inputting intensity, improved the energy accumulating efficiency, and inhibited the energy releasing degree.

Superior electrostrictive strain achieved under low electric fields in relaxor ferroelectric polymers

2019 ◽  
Vol 7 (10) ◽  
pp. 5201-5208 ◽  
Author(s):  
Zhicheng Zhang ◽  
Xiao Wang ◽  
Shaobo Tan ◽  
Qing Wang
Keyword(s):  
Energy Density ◽  
Energy Conversion ◽  
Electric Fields ◽  
Elastic Energy ◽  
Energy Conversion Efficiency ◽  
Relaxor Ferroelectric ◽  
Ferroelectric Polymers ◽  
Elastic Energy Density ◽  
Electromechanical Responses ◽  
Electromechanical Performance

A relaxor ferroelectric polymer exhibits record electromechanical performance, including the largest electrostrain of −13.4%, the highest elastic energy density of 3.1 J cm−3 and the best energy conversion efficiency of 0.5, among the known ferroelectric polymers. Notably, the excellent electromechanical responses are realized under much lower fields than those of ferroelectric polymers.

scholarly journals Sliding Impact Mechanism of Square Roadway Based on Complex Function Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Decheng Ge ◽  
Fuxing Jiang ◽  
Cunwen Wang ◽  
Yang Chen ◽  
Chunyu Dong ◽  
...  
Keyword(s):  
Energy Density ◽  
Plastic Zone ◽  
Elastic Energy ◽  
Surrounding Rock ◽  
Failure Zone ◽  
Rock Stress ◽  
Elastic Energy Density ◽  
Four Corners ◽  
Original Rock ◽  
Shear Slip

To clarify the process of stress change and plastic zone evolution of square roadways under high-stress conditions, the rotational square expansion plastic zone evolution model of square roadway was established by theoretical analysis, numerical simulation, and engineering verification. The shear slip impact stress criterion of square roadway based on complex variable function theory was studied, and the law of surrounding rock stress distribution, plastic zone expansion, elastic energy density, local energy release rate (LERR), and total energy release of square roadway were analyzed. The results show that the compressive stress is concentrated in the four corners of the roadway after the roadway excavated and transfers with the change of plastic zone. Main shear failures start from the four corners and develop in a rotating square shape, forming square failure zones I and II. The square failure zone I is connected with the roadway contour and rotated 45°. The square failure zone II is connected with the square failure zone I and rotated 45°. When the original rock stress is low, the surrounding rock tends to be stable after the square shear slip line field formed. When the original rock stress is high, the shear failure of the surrounding rock continues to occur after the square failure zone II formed, showing a spiral slip line. Corners of the square roadway and square failure zones I and II are the main energy accumulation and release areas. The maximum elastic energy density and LERR increase exponentially with the ratio of vertical stress to uniaxial compressive strength (Ic). When square corners of the roof are changed to round corners, the plastic zone of the roof expands to form an arch structure. The maximum elastic energy density decreases by 22%, which reduces the energy level and possibility of rock burst. This study enriches the failure mechanism of roadway sliding impact. It can provide a basic theoretical reference for the design of the new roadway section and support form based on the prevention of rock burst.

scholarly journals Measuring Elastic Energy Density of Bulk Metallic Glasses by Nanoindentation

2006 ◽  
Vol 47 (8) ◽  
pp. 1981-1984 ◽  
Author(s):  
K. Wang ◽  
D. Pan ◽  
M. W. Chen ◽  
W. Zhang ◽  
X. M. Wang ◽  
...  
Keyword(s):  
Energy Density ◽  
Metallic Glasses ◽  
Elastic Energy ◽  
Bulk Metallic Glasses ◽  
Elastic Energy Density

High-Dielectric-Constant All-Organic/Polymeric Composite Actuator Materials

2003 ◽  
Vol 785 ◽  
Author(s):  
Cheng Huang ◽  
Ji Su ◽  
Q.M. Zhang
Keyword(s):  
Dielectric Constant ◽  
Energy Density ◽  
Electric Fields ◽  
Elastic Energy ◽  
High Dielectric Constant ◽  
High Strain ◽  
Polymeric Materials ◽  
Field Type ◽  
Elastic Energy Density ◽  
High Dielectric

ABSTRACTAmong various electroactive polymer (EAP) actuator materials developed recently, the class of EAPs whose responses are stimulated by external electrical fields (often known as the field type EAPs) is especially attractive due to their high strain level and elastic energy density. However, for most field type EAPs, dielectric constant is low, generally less than 10. Consequently, these polymers usually require high electric fields (>100 V/μm) to generate high elastic energy density which limits their applications. In this paper, we will investigate some avenues to significantly raise the dielectric constant and electromechanical response in field type polymeric materials. By exploiting an all-organic composite approach in which high-dielectric-constant organic particulates were blended with a polymer matrix, a polymeric-like material can reach a dielectric constant higher than 400, which results in a significant reduction of the applied field to generate high strain with high elastic energy density. An all-polymer high-dielectric-constant (K>1,000 @1 kHz) percolative composite material was fabricated by the combination of conductive polyaniline particles (K>105) within a fluoroterpolymer matrix (K>50). These high-K polymer hybrid materials also exhibit high electromechanical responses under low applied fields. In addition, a three-component all-organic composite was designed and prepared to improve the dielectric constant and the electromechanical response, as well as the stability of the composites, in which a high-dielectric-constant organic dielectric phase and an organic conductive phase were embedded into the soft dielectric elastomer matrix.

The Reduction of Elastic Energy Density in InN Growth on (hkl)-Oriented Planes

2009 ◽  
Vol 48 (5) ◽  
pp. 051002 ◽  
Author(s):  
Bernard Gil ◽  
Olivier Briot ◽  
Pierre Bigenwald
Keyword(s):  
Energy Density ◽  
Elastic Energy ◽  
Elastic Energy Density

Separation of compressibility and shear deformation in the elastic energy density (L)

2004 ◽  
Vol 116 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Mark F. Hamilton ◽  
Yurii A. Ilinskii ◽  
Evgenia A. Zabolotskaya
Keyword(s):  
Energy Density ◽  
Shear Deformation ◽  
Elastic Energy ◽  
Elastic Energy Density

scholarly journals Numerical Analysis of Roadway Rock-Burst Hazard Under Superposed Dynamic and Static Loads

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3761 ◽  
Author(s):  
Kong ◽  
Jiang ◽  
Jiang ◽  
Wu ◽  
Chen ◽  
...  
Keyword(s):  
Energy Density ◽  
Rock Burst ◽  
Elastic Energy ◽  
Dynamic Load ◽  
Static Loading ◽  
Static Load ◽  
Dynamic Loads ◽  
Loading Conditions ◽  
Static Loads ◽  
Elastic Energy Density

Microseismic events commonly occur during the excavation of long wall panels and often cause rock-burst accidents when the roadway is influenced by dynamic loads. In this paper, the Fast Lagrangian Analysis of Continua in 3-Dimensions (FLAC3D) software is used to study the deformation and rock-burst potential of roadways under different dynamic and static loads. The results show that the larger the dynamic load is, the greater the increase in the deformation of the roadway under the same static loading conditions. A roadway under a high static load is more susceptible to deformation and instability when affected by dynamic loads. Under different static loading conditions, the dynamic responses of the roadway abutment stress distribution are different. When the roadway is shallow buried and the dynamic load is small, the stress and elastic energy density of the coal body in the area of the peak abutment stress after the dynamic load are greater than the static calculations. The dynamic load provides energy storage for the coal body in the area of the peak abutment stress. When the roadway is deep, a small dynamic load can still cause the stress in the coal body and the elastic energy density to decrease in the area of the peak abutment stress, and a rock-burst is more likely to occur in a deep mine roadway with a combination of a high static load and a weak dynamic load. When the dynamic load is large, the peak abutment stress decreases greatly after the dynamic loading, and under the same dynamic loading conditions, the greater the depth the roadway is, the greater the elastic energy released by the dynamic load. Control measures are discussed for different dynamic and static load sources of rock-burst accidents. The results provide a reference for the control of rock-burst disasters under dynamic loads.

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