Attenuation in sand: an exploratory study on the small-strain behavior and the influence of moisture condensation

2007 ◽  
Vol 9 (6) ◽  
pp. 365-376 ◽  
Author(s):  
Y.-H. Wang ◽  
J. C. Santamarina
Keyword(s):  
Exploratory Study ◽  
Small Strain ◽  
Strain Behavior ◽  
Moisture Condensation

scholarly journals Small Strain Behavior of Geomaterials: Modelling of Strain Rate Effects

1997 ◽  
Vol 37 (2) ◽  
pp. 127-138 ◽  
Author(s):  
Hervé Di Benedetto ◽  
Fumio Tatsuoka
Keyword(s):  
Strain Rate ◽  
Small Strain ◽  
Strain Rate Effects ◽  
Strain Behavior ◽  
Rate Effects

The Use of Line and Point Contacts in Determining Lubricant Rheology Under Low Slip Elastohydrodynamic Conditions

1983 ◽  
Vol 105 (2) ◽  
pp. 280-287 ◽  
Author(s):  
D. M. Heyes ◽  
C. J. Montrose
Keyword(s):  
Maxwell Model ◽  
Small Strain ◽  
Elastic Behavior ◽  
Point Contacts ◽  
Strain Behavior ◽  
Mineral Oils ◽  
Convolution Integral Equation ◽  
Shear Relaxation ◽  
Maximum Contact ◽  
Contact Pressures

A theoretical study has been made of the elastohydrodynamic small strain behavior of lubricants in line and point contacts. The model for the lubricants is more realistic than those proposed to date and involves a reformulation of the Maxwell model in terms of a Volterra convolution integral equation. In addition to being more physically appealing, the approach can be easily generalized to describe coupled structural and shear relaxation of a nonexponential nature. The calculations predict that certain mineral oils change from exhibiting compressional viscoelastic to elastic behavior at maximum contact pressures and rolling speeds of order 0.5 GPa and 1.0 m/s.

Stress-Strain Behavior of Randomly Crosslinked Polydimethylsiloxane Networks

1982 ◽  
Vol 55 (4) ◽  
pp. 1108-1122
Author(s):  
M. Gottlieb ◽  
C. W. Macosko ◽  
T. C. Lepsch
Keyword(s):  
Large Strain ◽  
Strain Energy Function ◽  
Small Strain ◽  
Careful Analysis ◽  
Relative Magnitude ◽  
Polymer Backbone ◽  
Strain Behavior ◽  
Strain Data ◽  
Crosslinked Networks ◽  
Good Agreement

Abstract We have demonstrated by means of our small-strain data that suppression of junction fluctuations cannot solely account for the discrepancy between experimental modulus values and the predictions of the phantom-network theory. The good agreement between the intercepts in Figures 3 and 4 and the value of GN0 leaves little doubt regarding the relation between the two and the validity of the model represented by Equation (12). Further experiments should be carried out on materials with higher GN0 values than the PDMS chains used here. This will magnify the contribution of trapped entanglements and will demonstrate more clearly the effects discussed here. Further study is also required in order to understand the role played by the polymer backbone on the amount of junction suppression. The question raised by Dossin and Graessley as to whether differences in h values for different networks are due to differences in structure between randomly crosslinked and end-linked networks or to differences in the relative magnitude of topological contributions for different polymers was answered by this work. The agreement of the h value obtained here with those obtained for endlinked PDMS networks indicates that no inherent differences in structure exist between endlinked and crosslinked networks and that differences in polymer backbone are responsible for the values of h obtained. Objections that radiation crosslinked networks are somehow not suitable for testing rubber elasticity theories should also be laid to rest by the good agreement of our results with those of Langley and Polmanteer. The large-strain data obtained here show the ability of Flory's strain energy function to correctly model tension-compression data over the range of crosslink densities covered by this work. Edwards' model did not agree well with our data for low degree of crosslinking samples. Further work is still required since our data exhibited relatively small deviations from Mooney-Rivlin behavior. Finally, the extreme importance of the careful analysis of the materials used, the reaction employed, and the resulting networks was demonstrated. The simplest available method for the verification of the network structure is by the determination of the sol fraction. The extraction of solubles in the case of highly crosslinked networks was found to be susceptible to weighing uncertainty and the presence of unreactive material. The former can be avoided by the use of larger samples, while the latter could be removed by vacuum stripping for our material.

On the Small Strain Behavior of Peroxide Crosslinked Natural Rubber

1986 ◽  
Vol 59 (1) ◽  
pp. 130-137 ◽  
Author(s):  
Gregory B. McKenna ◽  
Louis J. Zapas
Keyword(s):  
Energy Density ◽  
Density Function ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Scaling Law ◽  
Small Strain ◽  
Constant Length ◽  
Strain Behavior ◽  
Small Strains ◽  
Strain Energy Density Function

Abstract Torque and normal force measurements on a cylinder subjected to torsion at constant length were used to study the behavior of NR crosslinked with 5 phr dicumyl peroxide. The derivatives of the strain-energy density function ∂W/∂I1 and ∂W/∂I2 were calculated from the data using the scaling law of Penn and Kearsley. The new results extend the limit of small strains at which the strain-energy density function derivatives have been measured to γ<0.005 and further confirm our previous results that for peroxide-crosslinked NR, ∂W/∂I2 does not become negative at small strain, contrary to several reports in the literature. Reduced stress was determined for the rubber by using the approach of Kearsley and Zapas to calculate the derivative w′(λ) of the Valanis-Landel form of the strain energy function. The results were compared with the measured values for reduced stress in tension and compression at small strains. While the deviation between the predictions and the experimental behavior do not exceed 6%, the characters of the calculated and measured reduced stress plots are different. The measurements in torsion were not obtained at small enough strains to enable direct comparison with the extension/compression behavior at |ε|<0.002. Extrapolation of the results did not produce the anomalous cusp observed in the reduced stress for 0.998<1/λ<1.002 which was reported in our previous study. The fact that torsional data do not show the cusp offers support to the Kearsley suggestion that at these extremely small deformations, rubber compressibility may play an important role in the stress-strain behavior. This could also explain the apparent discrepancy between the predicted Valanis-Landel behavior and the observed behavior. Future work involving higher precision experiments is required to resolve the matter.

scholarly journals Laboratory study of small-strain behavior of a compacted silty sand

2013 ◽  
Vol 50 (2) ◽  
pp. 179-188 ◽  
Author(s):  
Ana Heitor ◽  
Buddhima Indraratna ◽  
Cholachat Rujikiatkamjorn
Keyword(s):  
Moisture Content ◽  
Structural Changes ◽  
Initial Moisture Content ◽  
Small Strain ◽  
Matric Suction ◽  
Point Of View ◽  
Silty Sand ◽  
Degree Of Saturation ◽  
Compacted Soil ◽  
Strain Behavior

Small-strain behavior is a key indicator for assessing the performance of compacted fills. Compaction conditions, i.e., initial moisture content and applied energy, govern compaction effectiveness and thus, the structure and matric suction of compacted soil. This paper presents an experimental study of the small-strain behavior of compacted silty sand prepared with different compaction conditions. Specimens with varying initial moisture contents and compaction energies were tested with bender elements to determine the small-strain shear modulus (G0), while the post-compaction matric suction was measured using the filter paper method and tensiometer. The experimental data suggest a pronounced relationship between G0 and the degree of saturation (Sr) of the as-compacted soil specimens. X-ray computed tomography (CT) scans were performed to examine structural changes of selected specimens upon compaction. The laboratory results are also examined in light of common end-product specifications, which show that it is beneficial to compact the soil slightly dry of optimum moisture content from the modulus point of view.

A Direct Simple Shear Device for Measuring Small-Strain Behavior

1995 ◽  
Vol 18 (1) ◽  
pp. 69 ◽  
Author(s):  
HJ Pincus ◽  
M Doroudian ◽  
M Vucetic
Keyword(s):  
Simple Shear ◽  
Small Strain ◽  
Strain Behavior ◽  
Direct Simple Shear

Determination, Derivation, Influence and Discussions of Parameters for Deformation Analyses with Duncan-Chang Modified E-B Model

2011 ◽  
Vol 90-93 ◽  
pp. 157-164
Author(s):  
Han Peng Liu ◽  
Dong Yuan Wang ◽  
Zhi Jun Ma
Keyword(s):  
Laboratory Tests ◽  
Small Strain ◽  
Hebei Province ◽  
Experimental Results ◽  
Model Parameters ◽  
Horizontal Deformation ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Confining Pressures ◽  
New Apparatus

This paper presents a study on influence of model parameters on deformation analyses with Duncan-Chang Modified Nonlinear Stress-strain (E-B) model for an ore mining tailings located in Chengde, Hebei Province of China. How to determine and derive these parameters from the laboratory experimental results was introduced first. Findings from numerical analyses performed with Midas GTS indicate that model parameters K and n most significantly affect the vertical and horizontal deformation respectively. Based on the analysis, the accuracy and effectiveness of these parameters were discussed further. Principles of the model and the parameter derivations suggest the model and parameters work better for small strain cases, hence model parameters shall be better determined with laboratory tests with low confining pressures or using new apparatus to measure small strain behavior of soil to ensure analysis results reliable.

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