Creep Deformation and Gas Permeability in Fractured Claystone Under Various Stress States

Based on the low permeability raw coal samples of coal seams of Daichiba coal mine of Guangwang group, we study the change of permeability under different stress states by a self-developed three-axis penetration device. It is proved by experiments that the permeability of coal sample increases rapidly along with the growing of the pressure at the procedure of loading at lower actual stress levels whose rules of changes is the function of negative exponent. In the process of unloading, rate of permeability increase slowly with the reduction of effective stress. It will greatly improved when the effective stress drops to a certain level, and this conformed to power function law. As the influence of coal seam gas permeability solid coupling factors is very complex, the normalized treatment for the factors has done by defining pressure-sensitive effect coefficient of coal samples permeability. Based on the results of the test to establish the relationship between pressure sensitive effect index and effective stress, this relationship reflects the trend of the coal sample permeability changes in the effective stress. And derive a functional relationship based on the coal sample of the pressure-sensitive effect index of permeability and effective stress.

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Constitutive relations describing creep deformation for multi-axial time-dependent stress states

Journal of the Mechanics and Physics of Solids ◽

10.1016/0022-5096(81)90013-2 ◽

1981 ◽

Vol 29 (1) ◽

pp. 13-33 ◽

Cited By ~ 5

Author(s):

L.N. McCartney

Keyword(s):

Creep Deformation ◽

Constitutive Relations ◽

Time Dependent ◽

Stress States

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Comparison of Substructures Between Uniaxial and Biaxial Deformation in 1100-0 Aluminum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096989 ◽

1981 ◽

Vol 39 ◽

pp. 52-53

Author(s):

D. L. Rohr ◽

S. S. Hecker

Keyword(s):

Plastic Strain ◽

Cell Walls ◽

Room Temperature ◽

Mechanical Response ◽

Biaxial Tension ◽

Initial Deformation ◽

Uniaxial Deformation ◽

Biaxial Deformation ◽

Stress States ◽

Comprehensive Study

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.

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Deformation and stress states along the central segment of the Philippine Fault: implications to wrench fault tectonics

Journal of Asian Earth Sciences ◽

10.1016/s1367-9120(97)00001-1 ◽

1997 ◽

Vol 15 (2-3) ◽

pp. 107-119

Author(s):

M Aurelio

Keyword(s):

Central Segment ◽

Fault Tectonics ◽

Stress States ◽

Wrench Fault

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Short Stress State Questionnaire

European Journal of Psychological Assessment ◽

10.1027/1015-5759/a000200 ◽

2015 ◽

Vol 31 (1) ◽

pp. 20-30 ◽

Cited By ~ 28

Author(s):

William S. Helton ◽

Katharina Näswall

Keyword(s):

Stress State ◽

Factor Structure ◽

Human Performance ◽

Self Report ◽

Confirmatory Factor ◽

Stress States ◽

Related Stress ◽

Using Data ◽

Task Conditions ◽

Multiple Samples

Conscious appraisals of stress, or stress states, are an important aspect of human performance. This article presents evidence supporting the validity and measurement characteristics of a short multidimensional self-report measure of stress state, the Short Stress State Questionnaire (SSSQ; Helton, 2004 ). The SSSQ measures task engagement, distress, and worry. A confirmatory factor analysis of the SSSQ using data pooled from multiple samples suggests the SSSQ does have a three factor structure and post-task changes are not due to changes in factor structure, but to mean level changes (state changes). In addition, the SSSQ demonstrates sensitivity to task stressors in line with hypotheses. Different task conditions elicited unique patterns of stress state on the three factors of the SSSQ in line with prior predictions. The 24-item SSSQ is a valid measure of stress state which may be useful to researchers interested in conscious appraisals of task-related stress.

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STRUCTURAL ANISOTROPY OF AMORPHOUS ALLOYS INDUCED BY MECHANICAL CREEP DEFORMATION

Le Journal de Physique Colloques ◽

10.1051/jphyscol:19858100 ◽

1985 ◽

Vol 46 (C8) ◽

pp. C8-623-C8-627 ◽

Cited By ~ 2

Author(s):

Y. Suzuki ◽

J. Haimovich ◽

T. Egami

Keyword(s):

Creep Deformation ◽

Amorphous Alloys ◽

Structural Anisotropy ◽

Mechanical Creep

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Évaliation of stress states and mechanical properties of rolled products using electromagnetic and ultrasonic methods

Matériaux & Techniques ◽

10.1051/mattech:2004020 ◽

2004 ◽

Vol 92 (3-4) ◽

pp. 63-69

Author(s):

E. Schneider

Keyword(s):

Mechanical Properties ◽

Ultrasonic Methods ◽

Stress States

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Masonry: the brittle or plastic material?

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2019.03.22-28 ◽

2019 ◽

pp. 22-28

Keyword(s):

Plastic Material ◽

Experimental Studies ◽

Point Of View ◽

Plastic Properties ◽

Plastic Deformations ◽

Base Materials ◽

Stress States ◽

Creep Deformations ◽

Structural Point

The results of experimental studies of masonry on the action of dynamic and static (short-term and long-term) loads are presented. The possibility of plastic deformations in the masonry is analyzed for different types of force effects. The falsity of the proposed approach to the estimation of the coefficient of plasticity of masonry, taking into account the ratio of elastic and total deformations of the masonry is noted. The study of the works of Soviet scientists revealed that the masonry under the action of seismic loads refers to brittle materials in the complete absence of plastic properties in it in the process of instantaneous application of forces. For the cases of uniaxial and plane stress states of the masonry, data on the coefficient of plasticity obtained from the experiment are presented. On the basis of experimental studies the influence of the strength of the so-called base materials (brick, mortar) on the bearing capacity of the masonry, regardless of the nature of the application of forces and the type of its stress state, is noted. The analysis of works of prof. S. V. Polyakov makes it possible to draw a conclusion that at the long application of the load, characteristic for the masonry are not plastic deformations, but creep deformations. It is shown that the proposals of some authors on the need to reduce the level of adhesion of the mortar to the brick for the masonry erected in earthquake-prone regions in order to improve its plastic properties are erroneous both from the structural point of view and from the point of view of ensuring the seismic resistance of structures. It is noted that the proposal to assess the plasticity of the masonry of ceramic brick walls and large-format ceramic stone with a voidness of more than 20% is incorrect, and does not meet the work of the masonry of hollow material. On the basis of the analysis of a large number of research works it is concluded about the fragile work of masonry.

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