Effect of static shear stress on the cyclic resistance of sands in simple shear loading

2011 ◽  
Vol 48 (10) ◽  
pp. 1471-1484 ◽  
Author(s):  
Siva Sivathayalan ◽  
Da Ha
Keyword(s):  
Shear Stress ◽  
Simple Shear ◽  
Shear Loading ◽  
Cyclic Resistance ◽  
Static Shear

scholarly journals Non-coaxiality of sand under bi-directional shear loading

2018 ◽  
Vol 5 (5) ◽  
pp. 172076 ◽  
Author(s):  
Yao Li ◽  
Yunming Yang
Keyword(s):  
Shear Stress ◽  
Strain Rate ◽  
Simple Shear ◽  
Shear Test ◽  
Shear Loading ◽  
Shear Behaviour ◽  
Shear Stresses ◽  
Simple Shear Test ◽  
Principal Axes ◽  
Angle Difference

This study aims to investigate the effect of consolidation shear stress magnitude on the shear behaviour and non-coaxiality of soils. In previous drained bi-directional simple shear test on Leighton Buzzard sand, it is showed that the level of non-coaxiality, which is indicated by the angle difference between the principal axes of stresses and the corresponding principal axes of strain rate tensors, is increased by increasing angle difference between the direction of consolidation shear stress and secondary shearing. This paper further investigated the relation and includes results with higher consolidation shear stresses. Results agree with the previous relation, and further showed that increasing consolidation shear stresses decreased the level of non-coaxiality in tests with angle difference between 0° and 90°, and increased the level of non-coaxiality in tests with angle difference between 90° and 180°.

scholarly journals Undrained Cyclic Response and Resistance of Saturated Calcareous Sand considering Initial Static Shear Effect

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Baojian Li ◽  
Panpan Guo ◽  
Gaoyun Zhou ◽  
Zhe Wang ◽  
Gang Lei ◽  
...  
Keyword(s):  
Shear Stress ◽  
Relative Density ◽  
Shear Stresses ◽  
Loose Sand ◽  
Calcareous Sand ◽  
Cyclic Shear ◽  
Cyclic Response ◽  
Dense Sand ◽  
Cyclic Resistance ◽  
Static Shear

Sand elements in the natural or manmade field have often undergone initial static shear stresses before suffering cyclic loading. To explore the effect of static shear stress, a series of undrained cyclic triaxial tests were performed on dense and loose calcareous sand under different initial and cyclic shear stresses. The triaxial test results are used to describe the effect of static shear stress on the cyclic response of the calcareous sand with different relative density. Cyclic mobility, flow deformation, and residual deformation accumulation are the three main failure modes under varying static and cyclic shear stress levels. The cyclic resistance of dense sand is greater than that of loose sand, but the initial static stress has different effects on the cyclic resistance of the two kinds of sand. The dense sand owns a higher cyclic resistance with SSR increasing, while for the loose sand, 0.12 is the critical SSR corresponding to the lowest value of the cyclic resistance. The dense sand has more fast accumulation of dissipated energy, compared with loose sand. Additionally, an exponential relationship is established between static shear stress, relative density, and normalized energy density.

Influence of Compression upon the Shear Properties of Bonded Rubber Blocks

1980 ◽  
Vol 53 (5) ◽  
pp. 1133-1144 ◽  
Author(s):  
L. S. Porter ◽  
E. A. Meinecke
Keyword(s):  
Shear Stress ◽  
Shear Modulus ◽  
Simple Shear ◽  
Compressive Force ◽  
Strain Curve ◽  
Shear Loading ◽  
Total Force ◽  
Strain Response ◽  
Stress Strain ◽  
Spring Rate

Abstract Rubber has a stress-strain response to compression-shear loadings that is the same as its stress-strain response to simple shear loadings. However, its load-deflection response to the compression-shear loading is not the same as its simple shear response. In determining the stress-strain relationship of the compression-shear loading from the load-deflection responses, three factors must be considered. First, the compression of the sample gives a lower rubber thickness. After calculating the strain, the lower thickness will give a higher strain than the original thickness at an equal deflection. Second, the compression gives a larger surface area due to bulging of the rubber. The higher area would result in a lower stress than the original area at an equal load. Third, the force that is necessary to compress the rubber block is stored in the rubber. When the rubber is sheared, the shear vector of the compressive force aides in deflecting the rubber. Therefore, the shear force vector would be added to the recorded load to determine the total force needed to shear the rubber. The resulting shear stress would be higher than the shear stress calculated by using the recorded load in calculating the shear stress. With all three factors accounted for, the shear stress-strain of the rubber is the same for the compressed part as it is for the uncompressed part. Therefore, the rubber's shear modulus, the slope of the shear stress-strain curve, has not been affected by the superimposed compression and remains an inherent property of the rubber. When designing a part to be used in a compression-shear application, one can use the shear and compression moduli normally obtained for shear and compression applications. The compression modulus would be used for determining the compressive spring rate and the amount of force used in lowering the shear spring rate. The shear modulus would be used to determine the shear rate by taking into account the geometry changes and the force due to compression.

Cyclic loading response of loose air-pluviated Fraser River sand for validation of numerical models simulating centrifuge tests

2005 ◽  
Vol 42 (2) ◽  
pp. 550-561 ◽  
Author(s):  
Dharma Wijewickreme ◽  
Somasundaram Sriskandakumar ◽  
Peter Byrne
Keyword(s):  
Cyclic Loading ◽  
Simple Shear ◽  
Mechanical Response ◽  
Shear Loading ◽  
Shear Stresses ◽  
Fraser River ◽  
River Sand ◽  
Cyclic Shear ◽  
Direct Simple Shear ◽  
Static Shear

Cyclic loading response of loose Fraser River sand was investigated, as input to numerical simulation of centrifuge physical models, using constant-volume direct simple shear tests conducted with and without initial static shear stress condition. Although the observed trends in mechanical response were similar, air-pluviated specimens were more susceptible to liquefaction under cyclic loading than their water-pluviated counterparts. Densification due to increasing confining stress (stress densification) significantly increased the cyclic resistance of loose air-pluviated sand, with strong implications for the interpretation of observations from centrifuge testing. The stress densification effect, however, was not prominent in the case of water-pluviated specimens. The differences arising from the two specimen reconstitution methods can be attributed to the differences in particle structure and highlight the importance of fabric effects in the assessment of the mechanical response of sands. The initial static shear stresses appear to reduce the cyclic shear resistance of loose air-pluviated sand in simple shear loading, in contrast to the increases in resistance reported on the basis of data from triaxial testing. Data from laboratory element tests that closely mimic the soil fabric and loading modes of the centrifuge specimens are essential for meaningful validation of numerical models.Key words: liquefaction of sands, air-pluviation, cyclic loading, direct simple shear testing, specimen preparation, fabric.

Application of Critical State Approach to Liquefaction Resistance of Sand–Silt Mixtures under Cyclic Simple Shear Loading

2021 ◽  
Vol 147 (3) ◽  
pp. 04020177
Author(s):  
Daniela Dominica Porcino ◽  
Theodoros Triantafyllidis ◽  
Torsten Wichtmann ◽  
Giuseppe Tomasello
Keyword(s):  
Simple Shear ◽  
Critical State ◽  
Shear Loading ◽  
Liquefaction Resistance

Influences of initial static shear stress on the cyclic behaviour of over consolidated soft marine clay

2021 ◽  
Vol 224 ◽  
pp. 108747
Author(s):  
Jun Wang ◽  
Ming Dai ◽  
Yuanqiang Cai ◽  
Lin Guo ◽  
Yunguo Du ◽  
...  
Keyword(s):  
Shear Stress ◽  
Marine Clay ◽  
Cyclic Behaviour ◽  
Static Shear

A NEW ORGANIC/INORGANIC HYBRID WITH HIGH ELECTRORHEOLOGICAL ACTIVITY

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2454-2460 ◽  
Author(s):  
X. P. ZHAO ◽  
X. DUAN
Keyword(s):  
Activation Energy ◽  
Shear Stress ◽  
Necessary Conditions ◽  
Sol Gel ◽  
Root Temperature ◽  
Sedimentation Stability ◽  
Inorganic Hybrid ◽  
Active Particles ◽  
Static Shear

In-situ sol-gel method to prepare colloidal hybrids of surfactant modified polysucchride and titanium oxide has been presented, and experiments indicated these highly ER active particles exhibited a remarkable ER effect. The static shear stress can be up to 37 k Pa (shear rate 5 S -1) under DC field of 4 kV/mm at root temperature, well above that of simple blends of starch and TiO 2. In the meanwhile, temperature dependence and sedimentation stability were also greatly improved. Based on recent experimental facts, we find that dielectric properties and surface (interface) activity are two necessary conditions fulfilling the requirement of high ER activity. Adequate grinding of particles with oil can effectively enhance the shear stress, which may be owed to the decline of the activation energy needed for restructuring. It has provided us a new horizon for preparation of excellent ER materials and further studies should be continued to make.

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