scholarly journals Test Study on the Creep Behaviors of Tianjin Clays

2019 ◽  
Vol 136 ◽  
pp. 07029
Author(s):  
Gang Li ◽  
Zhen Yan ◽  
Jinli Zhang ◽  
Jia Liu ◽  
Yu Xi
Keyword(s):  
Strain Rate ◽  
Axial Strain ◽  
Deviatoric Stress ◽  
Test Results ◽  
Creep Tests ◽  
Creep Properties ◽  
Test Study ◽  
Undisturbed Samples ◽  
Calculation Results ◽  
Triaxial Creep

The drained triaxial creep tests were carriedout to investigate the relationshipsbetween axial strain and time, axial strain and deviatoricstress, and axial strain rate and time for the undisturbed samples of muddy clay and clay in Tianjin.Based on the creep test results, the Singh-Mitchell modelwas used for creep calculation. The results showed that the muddyclay and clay exhibited typical non-linear creep properties. The axial strain increasedwith time and then gradually tendedto be stable.The strain rate increasedasthe deviatoric stress increased, and the muddy clay and clay showedthe characteristics of attenuation creep under deviatoricstresses. The axial strain of muddy clay wassignificantly larger than that of clay, and reachedthestable state within 3000 minutes.Under low deviatoricstress, the slope of the isochronal curve was smaller; while under high deviatoric stress, the slope of the isochronal curve waslarger.The test results were in good agreement with the calculation results, which indicated that the Singh-Mitchell model wassuitable for describing the creep behaviorsof the undisturbed claysin Tianjin.

scholarly journals Influence of strain rate and heat treatments on tensile and creep properties of Zn-0.15Cu-0.07Ti alloys

DYNA ◽  
2016 ◽  
Vol 83 (195) ◽  
pp. 77-83 ◽  
Author(s):  
María José Quintana Hernández ◽  
José Ovidio García ◽  
Roberto González Ojeda ◽  
José Ignacio Verdeja
Keyword(s):  
Strain Rate ◽  
Room Temperature ◽  
Rolling Direction ◽  
Tensile Tests ◽  
Strain Rates ◽  
Creep Tests ◽  
Design Problems ◽  
Creep Properties ◽  
Heat Treated ◽  
Zn Alloys

The use of Cu and Ti in Zn alloys improves mechanical properties as solid solution and dispersoid particles (grain refiners) may harden the material and reduce creep deformation. This is one of the main design problems for parts made with Zn alloys, even at room temperature. In this work the mechanical behavior of a Zn-Cu-Ti low alloy is presented using tensile tests at different strain rates, as well as creep tests at different loads to obtain the value of the strain rate coefficient m in samples parallel and perpendicular to the rolling direction of the Zn strip. The microstructure of the alloy in its raw state, as well as heat treated at 250°C, is also analyzed, as the banded structure produced by rolling influences the strengthening mechanisms that can be achieved through the treatment parameters.

Experimental investigation on the creep behavior of an unsaturated clay

2014 ◽  
Vol 51 (6) ◽  
pp. 621-628 ◽  
Author(s):  
X.L. Lai ◽  
S.M. Wang ◽  
W.M. Ye ◽  
Y.J. Cui
Keyword(s):  
Strain Rate ◽  
Large Scale ◽  
Axial Strain ◽  
Creep Model ◽  
Three Gorges Reservoir Area ◽  
Hyperbolic Function ◽  
Creep Tests ◽  
Suction Control ◽  
Strain And Strain Rate ◽  
Influence Of Water

To better understand the long-term deformation of landslides with consideration of the influence of water content variation, a series of triaxial creep tests with suction control was conducted on clay specimens taken from one large-scale landslide in the Three Gorges Reservoir area in China. Results indicate that, in the double-logarithmic coordinates, the axial strain increases linearly and the axial strain-rate decreases linearly with the elapsed time; the axial strain and strain rate increase with increasing deviator stress levels and decreasing matric suction. For theoretical analysis, based on the simulation of the test results by an empirical creep model developed for saturated soils, a linear relationship was established between suction and one of the parameters of the model. Then, a revised model with consideration of suction effects was developed. In the revised model, a power function was adopted for the description of the strain–time relationship and a hyperbolic function was employed for the stress–strain relationship. Verification indicated that the calculated results were in good agreement with the experimental ones.

Small Punch Creep Testing Technique for Remnant Life Assessment

2014 ◽  
Vol 592-594 ◽  
pp. 739-743 ◽  
Author(s):  
J. Ganesh Kumar ◽  
K. Laha ◽  
M.D. Mathew
Keyword(s):  
Creep Test ◽  
Rupture Life ◽  
Life Assessment ◽  
Test Results ◽  
Creep Tests ◽  
Testing Technique ◽  
Creep Properties ◽  
Small Punch ◽  
Miniature Specimens ◽  
Deflection Rate

Small punch creep (SPC) testing technique is a material non-intensive testing technique for evaluating creep behavior of materials using miniature specimens. It can be used for remnant life assessment (RLA) studies on components in service, by scooping out limited material for testing without impairing the strength of component. In order to ensure the reliability of use of SPC technique for RLA, it is necessary to establish sound database on SPC properties of the material before putting into service. In this investigation, SPC technique was used to evaluate creep properties of 316LN stainless steel using specimens of size 10 x 10 x 0.5 mm. SPC tests were conducted in load controlled mode at 923 K and at various loads. SPC curves clearly exhibited primary, secondary and tertiary creep stages. The minimum deflection rate increased and rupture life decreased with an increase in applied load. Like in conventional creep test results, the minimum deflection rate obeyed Norton’s power law and Monkman-Grant relationship. SPC test was correlated with corresponding conventional creep test. Good correlation was established between creep rupture life values evaluated from SPC tests and conventional creep tests.

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 Experimental investigation on creep behavior of clastic rock

2020 ◽  
Vol 165 ◽  
pp. 03051
Author(s):  
Zhang Yu ◽  
Zhang Yan ◽  
Mei Song-hua
Keyword(s):  
Axial Strain ◽  
Triaxial Compression ◽  
Testing Machine ◽  
Creep Model ◽  
Test Results ◽  
Creep Failure ◽  
Creep Properties ◽  
Clastic Rock ◽  
Confining Pressures ◽  
The Relationship

Many deflected fault zones exist under the dam foundation Xiang-jiaba Hydropower Station in southwestern China. Clastic rock is the main medium with poor physical and mechanical properties. In or-der to study the creep properties of the clastic rock, triaxial compression creep experiments were carried out on a rock servo-controlling rheology testing machine. From the test results, it can be concluded that the clastic rock has obvious creep characteristics, and the time-dependent deformation is large. Based on the test results, the relationship between axial strain and time under different confining pressures is studied. The relationship between axial strain rates and deviatoric stress under different stress levels is also discussed in de-tail. Furthermore, the creep failure mechanism under different confining pressures is analyzed as well. Therefore, the creep law of the clastic rock specimen is gained. The relationship between the Burgers creep model and its parameters is obtained by fitting the creep curve with Burgers creep model. The result shows that Burgers model can accurately describe the creep properties of the clastic rock in Xiang-jiaba Hydro-power Project.

scholarly journals Study on the Creep Behaviors of Interactive Marine-Terrestrial Deposit Soils

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Zhen Yan ◽  
Gang Li ◽  
Jinli Zhang ◽  
Rui Zhang
Keyword(s):  
Creep Behavior ◽  
Axial Strain ◽  
Nonlinear Creep ◽  
Creep Tests ◽  
Creep Equation ◽  
One Dimensional ◽  
Consolidation Pressure ◽  
Deviator Stress ◽  
Consolidation Coefficient ◽  
Triaxial Creep

The interactive marine-terrestrial (IMT) deposit soils were formed in the complex depositional environment; their mechanical properties are different from the other deposits. The creep behaviors of Dalian clayey soils were studied according to one-dimensional creep tests and drained triaxial creep tests. Based on the creep test results, the empirical model was established to describe the one-dimensional creep behavior and triaxial creep behavior, respectively. The results showed that Dalian deposits have typical nonlinear creep behavior. With the increasing of consolidation pressure, the strain is increased, the stability time is extended, and the demarcation point between primary and secondary consolidation is more obvious. The deposits belong to medium to high secondary compressibility soil, and the secondary consolidation coefficient is decreased with the increasing of consolidation time and increased with consolidation pressure increasing. The ratio between secondary consolidation coefficient and compression index at different depths changes from 0.033 to 0.058, which conform to Mesri conclusion. Under low deviator stress, the creep processes showed the characteristic of attenuation creep and shear contraction. However, it showed the characteristic of acceleration creep, shear contraction, and shear dilatancy under damage deviator stress. The axial strain rate decreased with the increasing of creep time and increased with the deviator stress increasing, while the deviator stress has little effect on the m values. The tests results agree well with the calculation results, which showed that the creep equation is suitable for describing the creep behaviors of Dalian interactive marine-terrestrial deposits.

scholarly journals Spatial and temporal scales of anisotropic effects in ice-sheet flow

2003 ◽  
Vol 37 ◽  
pp. 40-48 ◽  
Author(s):  
Throstur Thorsteinsson ◽  
Edwin D. Waddington ◽  
Raymond C. Fletcher
Keyword(s):  
Strain Rate ◽  
Local Stress ◽  
Local Strain ◽  
Stress Pattern ◽  
Deviatoric Stress ◽  
Creep Tests ◽  
Spatial And Temporal Scales ◽  
Transition Zones ◽  
Ice Stream ◽  
Polar Ice Sheets

AbstractAlong most particle paths in polar ice sheets, ice experiences a slowly changing local deviatoric-stress pattern, and develops a fabric characteristic of its current stress state, in which there is generally a correspondence between non-zero strain-rate components and non-zero deviatoric-stress components. Where the stress pattern changes rapidly in special transition zones, fabric may evolve more slowly than the local stress field, and unusual or unexpected deformation patterns can result. The degree to which fabric tracks the local stress is determined by the relative characteristic times for changes in stress, given by the transition-zone width and ice velocity, and for changes in crystal orientation, given, in the absence of recrystallization, by the inverse of the local strain rate due to the principal stress. Recrystallization can significantly reduce the time-scale of fabric adjustment. We examine transition zones where ice (a) enters ice-stream margins, (b) is overrun by a migrating divide, and (c) flows through a strong saddle. Stress and fabric tend to be significantly misaligned in ice-stream margins and in flow through a saddle. When stresses that are markedly different from in situ stresses are applied to ice specimens during creep tests, deformation may be difficult to interpret.

scholarly journals Creep Behaviors of Methane Hydrate-Bearing Frozen Sediments

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 251 ◽  
Author(s):  
Yanghui Li ◽  
Peng Wu ◽  
Xiang Sun ◽  
Weiguo Liu ◽  
Yongchen Song ◽  
...  
Keyword(s):  
Strain Rate ◽  
Methane Hydrate ◽  
Axial Strain ◽  
Confining Pressure ◽  
Creep Tests ◽  
Creep Stage ◽  
Long Term Stability ◽  
Deviator Stress ◽  
Strain And Strain Rate

Creep behaviors of methane hydrate-bearing frozen specimens are important to predict the long-term stability of the hydrate-bearing layers in Arctic and permafrost regions. In this study, a series of creep tests were conducted, and the results indicated that: (1) higher deviator stress (external load) results in larger initial strain, axial strain, and strain rate at a specific elapsed time. Under low deviator stress levels, the axial strain is not large and does not get into the tertiary creep stage in comparison with that under high deviator stress, which can be even up to 35% and can cause failure; (2) both axial strain and strain rate of methane hydrate-bearing frozen specimens increase with the enhancement of deviator stress, the decrease of confining pressure, and the decrease of temperature; (3) the specimens will be damaged rather than in stable creep stage during creeping when the deviator stress exceeds the quasi-static strength of the specimens.

Axial compression stress path tests on artificial frozen soil samples in a triaxial device at temperatures just below 0 °C

2014 ◽  
Vol 51 (10) ◽  
pp. 1178-1195 ◽  
Author(s):  
Yuko Yamamoto ◽  
Sarah M. Springman
Keyword(s):  
Strain Rate ◽  
Axial Compression ◽  
Axial Strain ◽  
Deformation Behaviour ◽  
Acoustic Emissions ◽  
Piezoelectric Sensor ◽  
Past Research ◽  
Soil Samples ◽  
Frozen Soil ◽  
Test Results

This paper aims to assess the characteristics of the strength and creep properties of frozen soil under triaxial stress conditions at temperatures close to the thawing point. A series of triaxial constant rate of strain (CRS) and constant stress creep (CSC) tests was carried out in axial compression on artificially frozen soil samples at temperatures between –3.0 and –0.3 °C. Acoustic emissions, with a frequency range of 100–1000 kHz, were measured using a wide-band piezoelectric sensor to understand the mechanisms of the deformation behaviour and microstructural effects that control the response of the frozen soil specimens during the tests, especially at yield and approaching failure. The test results showed that the influence of a temperature increase close to the thawing point led to reduced shear strength and increased minimum axial strain rate. The test results were compared with data from similar experiments on artificial frozen and alpine permafrost specimens obtained from a past research project. It was observed that the acoustic emission response indicates a change in the physical process of deformation between microcrack formation and the reorientation of ice granules, depending on the strain rate.

Sign in / Sign up

Export Citation Format

Share Document