Mechanical properties of coal microcomponents under continuous indentation

Kossovich, E. L.; Dobryakova, N. N.; Эпштейн, С. А.; Белов, Д. С.

doi:10.1134/s1062739116041382

Cited by 16 publications

(4 citation statements)

References 8 publications

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“…More advanced micro and nanoindentation procedures and results of their applications to coals are presented in [33][34][35]. However, there are still many questions related to nanoindntation testing of coals.…”

Section: The Microhardness Value Is Calculated Asmentioning

confidence: 99%

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Mechanical, structural and scaling properties of coals: depth-sensing indentation studies

et al. 2019

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This paper discusses special features of mechanical behaviour of coals discovered using depth-sensing indentation (DSI) techniques along with other traditional methods of material testing. Many of the special features are caused by the presence of multiscale complex heterogeneous internal structure within the samples and brittleness of some coal components. Experimental methodology for studying mechanical properties of coals and other natural extreme materials like bones are discussed.It is argued that values of microhardness of bituminous coals correlate strongly with the maximum load, therefore the use of this parameter in application to coals may ⋆ Research was supported by the Russian Science Foundation (grant #16-17-10217) be meaningless. For analysis of the force-displacement curves obtained by DSI, both Oliver-Pharr and Galanov-Dub approaches are employed. It is argued that during nanoindentation, the integrity of the internal structure of a coal sample within a small area of high stress field near the tip of indenter may be destroyed. Hence, the standard approaches to mechanical testing of coals should be re-examined.

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Section: The Microhardness Value Is Calculated Asmentioning

confidence: 99%

“…The anthracite samples whose thickness was just 10 µm, were not transparent. Hence, another procedure of preparation of the coal samples was also used for the DSI experiments [33]. Namely, samples were manufactured from 1.…”

Section: The Microhardness Value Is Calculated Asmentioning

confidence: 99%

Mechanical, structural and scaling properties of coals: depth-sensing indentation studies

et al. 2019

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“…Knowing that coal is a rock type with bedding planes, previous researches have proved that the bedding angle plays an important role in rock strength, AE, and energy characteristics [27][28][29][30][31][32]. Moreover, Kossovich et al [33] found that the UCS and elastic modulus of coal specimens have significant anisotropy, which is related to the bedding angle. Song et al [34] found that a U-shaped distribution of UCS with anisotropy angle, the maximum intensity was observed on coal specimens with vertical bedding (CSVB), and the second-largest value was observed on coal specimens with parallel bedding (CSPB).…”

Section: Introductionmentioning

confidence: 99%

Loading Rate and Bedding Plane Coupled Effect Study on Coal Failure under Uniaxial Compression: Acoustic Emissions and Energy Dissipation Analysis

et al. 2022

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The mechanical behavior of coal is significantly influenced by the loading rate and bedding plane. In this paper, the uniaxial compression tests at different loading rates were conducted on coal specimens with vertical bedding (CSVB) and coal specimens with parallel bedding (CSPB), which were prepared by the coal with bursting liability from the Ordos deep mining areas, China. The results show that the uniaxial compressive strengths of CSVB and CSPB are positively correlated with the loading rate. The peak values of acoustic emission (AE) counts and accumulated absolute AE energy of CSVB and CSPB increase with the loading rate, and the AE parameters of CSVB are larger than those of CSPB. The variation rules of input energy density and elastic energy density are similar for CSVB and CSPB, but the variation rules of dissipated energy density in stage IV are different. As the axial load increases, the energy storage rate and energy dissipation rate of both coal specimen types increase and decrease, respectively. The bedding planes of coal and the loading conditions in the field should be fully considered when identifying the bursting liability of coal and forecasting coal burst. This study can provide a reference for coal burst warning and prevention under similar geological conditions in Ordos deep mining areas.

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“…Thus, for the correct description of the deformation process of rocks and coals in particular, it is necessary to use the Mohr -Coulomb model. Significant number of works have been devoted to the identification of mechanical properties for coal rocks [5][6][7][8]. By its nature and process of formation, coal is an extremely complex material that has many peculiarities such as anisotropy, rheology, the presence of internal stresses, inhomogeneous properties, fracturing and many others.…”

Section: Introductionmentioning

confidence: 99%

Studying of Elastoplastic Properties of Coal Specimens Using Indentation Technique

Vatul’yan¹,

Lyapin²,

Kossovich³

2018

MMI

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A numerical study on elsatoplastic properties in problem of coals specimen nanoindentation by Berkovich pyramid is presented. The stress-strain state of specimen during indentation is calculated using finite element method including complex elastoplastic behaviour on the basis of Drucker-Prager model. The effective axisymmetrical indenter of cone shape is introduced and used for the simulation. The influence of basic geometrical and material parameters of the solid model on the indentation curve is studied. In addition, some new form of indentation curve approximation is proposed. For all the results calculated, the sets of approximation parameters are given. Using modern nanoindentation equipment the number of real experiments were performed and comparison with the mathematical model is presented.

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Mechanical properties of coal microcomponents under continuous indentation

Cited by 16 publications

References 8 publications

Mechanical, structural and scaling properties of coals: depth-sensing indentation studies

Mechanical, structural and scaling properties of coals: depth-sensing indentation studies

Loading Rate and Bedding Plane Coupled Effect Study on Coal Failure under Uniaxial Compression: Acoustic Emissions and Energy Dissipation Analysis

Studying of Elastoplastic Properties of Coal Specimens Using Indentation Technique

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