Experimental Study of Uniaxial Compressive Strength of Gas Hydrate-Bearing Sediment at Constant Strain Rate

2012 ◽  
Author(s):  
Xiongfei Nie ◽  
Weiguo Liu ◽  
Yongchen Song ◽  
Jiafei Zhao ◽  
Rui Wang
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Power Function ◽  
Uniaxial Compressive Strength ◽  
Gas Hydrate ◽  
Failure Time ◽  
Constant Strain Rate ◽  
Test System ◽  
Synthetic Gas ◽  
Compressive Tests

The uniaxial compressive tests are conducted on synthetic gas hydrate-bearing sediment samples by using the low-temperature high-pressure triaxial test system. The effects of the temperature, the strain rate and the failure time on the uniaxial compressive strength of hydrate sediment are measured. The results indicate that: (a) The uniaxial compressive strength is sensitive to the change of temperature and increases exponentially as temperature decreases. (b) The uniaxial compressive strength of hydrate sediment changes with the strain rate obviously, and increases with the strain rate increasing following a power function. (c) The uniaxial compressive strength increases with the failure time decreasing following a power function.

scholarly journals The Mechanical Properties of Single Crystals of Pure Ice

1969 ◽  
Vol 8 (54) ◽  
pp. 463-473 ◽  
Author(s):  
S. J. Jones ◽  
J. W. Glen
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Single Crystals ◽  
Fracture Stress ◽  
Constant Strain Rate ◽  
Tensile Creep ◽  
Stress Dependence ◽  
Creep Tests ◽  
Dislocation Multiplication ◽  
Compressive Tests

AbstractResults obtained from tensile and compressive tests on pure ice single crystals at various temperatures down to −90°C are reported. At −50°C tensile creep tests give a continually increasing creep rate until fracture, as observed at higher temperatures. The stress dependence of the strain-rate is discussed. Fracture stress increases with decreasing temperature. Results from constant strain-rate compressive tests are compared with theoretical curves computed from Johnston’s (1962) theory of dislocation multiplication. A dislocation velocity of the order of 0.5×10−8 m s−1 is deduced for ice at −50°C.

Effects of Temperature and Strain-Rate on the Compressive Strength of Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 2619-2624
Author(s):  
Chuan Xiong Liu ◽  
Yu Long Li
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Peak Strain ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Compressive Strength Of Concrete ◽  
Pressure Bar ◽  
Increasing Temperature ◽  
Compressive Tests

Dynamic compressive tests were carried out for concrete specimens after exposure to temperatures 23°C, 400°C, 600°C and 800°C by using Split Hopkinson Pressure Bar(SHPB) apparatus. Cylindrical specimens with 98mm in diameter and 49mm in length were used in tests. The strain rates achieved in tests ranged from 30s-1 to 220s-1. The results showed that the compressive strength increases with increasing strain-rate, but decreases with the increase of temperature. However, the effect of strain-rate on improving the compressive strength of concrete decreases with the increase of temperature. Moreover, the strain-rate has an improvement on the peak strain of concrete, and the accretion rate increases with increasing temperature.

scholarly journals Plane-Strain Compressive Strength of Columnar-Grained and Granular-Snow Ice

1977 ◽  
Vol 18 (80) ◽  
pp. 505-516 ◽  
Author(s):  
R. Frederking
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Failure Mechanism ◽  
Plane Strain ◽  
Uniaxial Compressive Strength ◽  
Ice Cover ◽  
Anisotropic Structure ◽  
Compression Tests ◽  
Isotropic Structure ◽  
Plane Strain Case

Abstract An ice cover impinging on a long straight structure is assumed to be under a condition of plane strain. A technique is described for performing plane-strain compression tests, and results are presented for the strain-rate dependence of strength. The plane-strain compressive strength of ice having anisotropic structure (columnar-grained ice) is at least two and a half times the uniaxial compressive strength, whereas the plane-strain compressive strength of ice having an isotropic structure (granular-snow ice) is at most 25% greater than the uniaxial case. The greater plane-strain compressive strength of columnar grained ice when the loading and confining directions are in the plane of the ice cover, can be attributed to its anisotropic structure, which leads to a different failure mechanism for the plane-strain case.

scholarly journals The Effect of Test System Misalignment in the Dynamic Tension Test

1982 ◽  
Vol 104 (4) ◽  
pp. 285-290
Author(s):  
Han C. Wu ◽  
T. P. Wang ◽  
M. C. Yip
Keyword(s):  
Plastic Strain ◽  
Strain Rate ◽  
Constant Strain Rate ◽  
Test System ◽  
Tension Test ◽  
Neutral Axis ◽  
Dynamic Tension ◽  
Test Sheet

An analysis of test system misalignment is presented for dynamic tension test. Sheet type rectangular 1100-0 aluminum specimens are used for discussion. For a constant strain rate tension test, the strain rate is constant only on the neutral axis of the specimen. The lower the strain rate is, the more significant the misalignment errors become. The neutral axis will shift away from the centerline of the specimen as the plastic strain increases. But, it will reach a limit and will not completely move back to the centerline.

scholarly journals Field Test 1 of Compressive Strength of First-Year Sea Ice

1983 ◽  
Vol 4 ◽  
pp. 253-259 ◽  
Author(s):  
N. K. Sinha
Keyword(s):  
Compressive Strength ◽  
Sea Ice ◽  
Failure Time ◽  
Rate Sensitivity ◽  
Test System ◽  
First Year ◽  
Test Machine ◽  
Baffin Island ◽  
Test Results ◽  
Average Strain Rate

A test program undertaken in April 1981 on the uniaxial compressive strength of freshly recovered first-year columnar-grained sea ice at a portable field laboratory floating on top of the ice cover in Eclipse Sound, Baffin Island, Canadian Arctic, is reported. Using a small battery-operated test machine, both vertical and horizontal samples were tested so that the load could be applied either parallel or perpendicular to the axis of the columns. Rate sensitivity of the observed strength is discussed in terms of measured average strain-rate and average stress-rate to upper yield or failure. Strain and time aspects of the test results are considered as well. Although vertical samples showed considerably greater strength than horizontal samples, no significant differences were detected in the failure strains. Examination of the interdependence of failure stress and failure time revealed certain anomalies in the results for vertical samples that could be linked to the performance characteristics of the test machine. As such problems could be common to any test system, methods of analysis are proposed for rational examination of the results.

scholarly journals Experimental Study on the Influence of Moisture Content on the Mechanical Properties of Coal

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Mingxing Gao ◽  
Yongli Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Moisture Content ◽  
Uniaxial Compressive Strength ◽  
Poisson’S Ratio ◽  
Triaxial Compression ◽  
Test System ◽  
Poisson's Ratio ◽  
Compression Tests

Water injection in coal seams will lead to the increase of moisture content in coal, which plays an essential role in the physical and mechanical properties of coal. In order to study the influence of moisture content on the mechanical properties of soft media, the forming pressure (20 MPa) and particle size ratio (0-1 mm (50%), 1-2 mm (25%), and 2-3 mm (25%)) during briquette preparation were firstly determined in this paper. Briquettes with different moisture contents (3%, 6%, 9%, 12%, and 15%) were prepared by using self-developed briquettes. Uniaxial and triaxial compression tests were carried out using the RMT-150C rock mechanics test system. The results show that the uniaxial compressive strength and elastic modulus of briquette samples increase first and then decrease with the increase of briquette water, while Poisson’s ratio decreases first and then increases with the increase of briquette water. When the moisture content is around 9%, the maximum uniaxial compressive strength is 0.866 MPa, the maximum elastic modulus is 1.385 GPa, and Poisson’s ratio is at the minimum of 0.259. The compressive strength of briquettes increases with the increase of confining pressure. With the increase of moisture content, the cohesion and internal friction angle of briquettes first increased and then decreased.

scholarly journals Plane-Strain Compressive Strength of Columnar-Grained and Granular-Snow Ice

1977 ◽  
Vol 18 (80) ◽  
pp. 505-516 ◽  
Author(s):  
R. Frederking
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Failure Mechanism ◽  
Plane Strain ◽  
Uniaxial Compressive Strength ◽  
Ice Cover ◽  
Anisotropic Structure ◽  
Compression Tests ◽  
Isotropic Structure ◽  
Plane Strain Case

AbstractAn ice cover impinging on a long straight structure is assumed to be under a condition of plane strain. A technique is described for performing plane-strain compression tests, and results are presented for the strain-rate dependence of strength. The plane-strain compressive strength of ice having anisotropic structure (columnar-grained ice) is at least two and a half times the uniaxial compressive strength, whereas the plane-strain compressive strength of ice having an isotropic structure (granular-snow ice) is at most 25% greater than the uniaxial case. The greater plane-strain compressive strength of columnar grained ice when the loading and confining directions are in the plane of the ice cover, can be attributed to its anisotropic structure, which leads to a different failure mechanism for the plane-strain case.

Uniaxial Constant Compressive Stress Creep Tests on Sea Ice

1995 ◽  
Vol 117 (4) ◽  
pp. 283-289 ◽  
Author(s):  
N. K. Sinha ◽  
C. Zhan ◽  
E. Evgin
Keyword(s):  
Compressive Strength ◽  
Sea Ice ◽  
Strain Rate ◽  
Compressive Stress ◽  
Axial Strain ◽  
Acoustic Emissions ◽  
Constant Strain Rate ◽  
Rate Sensitivity ◽  
Load Test ◽  
Creep Tests

First-year columnar-grained sea ice from Resolute Passage (74° 42′ N, 94° 50′ W), off Barrow Strait in the Canadian High Arctic, was tested under constant uniaxial compressive stress applied normal to the length of the columns. Creep tests were performed at 263 K, 253 K, and 243 K in the stress range of 0.7 to 2.5 MPa, using prismatic samples with dimensions of 50 mm × 100 mm × 250 mm. Because three-dimensional creep data are extremely useful for developing constitutive equations, axial strain was measured in conjunction with the measurements of two lateral strains and acoustic emissions. The deformations were measured using displacement gages mounted on the samples. A description of the experimental procedures and the observations are presented here. One-to-one correspondence has been obtained between the present results on the dependence of minimum creep rate on stress and previous data on the dependence of uniaxial compressive strength on strain rate under constant strain rate. The strain-rate sensitivity of compressive strength can, therefore, be obtained from creep tests which can be performed by using simple dead-load test systems.

scholarly journals Effect of Sample and Grain Size on the Compressive Strength of Ice

1983 ◽  
Vol 4 ◽  
pp. 129-132 ◽  
Author(s):  
Stephen J. Jones ◽  
H. A. M. Chew
Keyword(s):  
Grain Size ◽  
Compressive Strength ◽  
Strain Rate ◽  
Sample Size ◽  
Uniaxial Compressive Strength ◽  
Size Range ◽  
Significant Dependence ◽  
Polycrystalline Ice

The effect of sample and grain size on the uniaxial compressive strength of polycrystalline ice has been investigated at -10°C, at a strain-rate of 5.5 × 10-4s-1The results show (a) that the sample size must be 12 or more times greater than the grain size for ft to have no effect on the strength and (b) that there is no significant dependence of compressive strength on grain size, within the grain-size range of 0.6 to 2.0 mm.

scholarly journals Plane-Strain Compressive Strength of Columnar-Grained and Granular-Snow Ice

1977 ◽  
Vol 19 (81) ◽  
pp. 657-658
Author(s):  
R. Frederking
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Failure Mechanism ◽  
Plane Strain ◽  
Uniaxial Compressive Strength ◽  
Ice Cover ◽  
Anisotropic Structure ◽  
Compression Tests ◽  
Isotropic Structure ◽  
Plane Strain Case

AbstractAn ice cover impinging on a long straight structure is assumed to be under a condition of plane strain. A technique is described for performing plane-strain compression tests, and results are presented for the strain-rate dependence of strength. The plane-strain compressive strength of ice having anisotropic structure (columnar-grained ice) is at least two and a half times the uniaxial compressive strength, whereas the plane-strain compressive strength of ice having an isotropic structure (granular-snow ice) is atmost 25% greater than the uniaxial case. The greater plane-strain compressive strength of columnar-grained ice, when the loading and confining directions are in the plane of the ice cover, can be attributed to its anisotropic structure, which leads to a different failure mechanism for the plane-strain case.

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