Elastic Modulus at High Frequency of Polymerically Stabilized Suspensions

Langmuir ◽  
2000 ◽  
Vol 16 (4) ◽  
pp. 1902-1909 ◽  
Author(s):  
P. A. Nommensen ◽  
M. H. G. Duits ◽  
D. van den Ende ◽  
J. Mellema
Keyword(s):  
Elastic Modulus ◽  
High Frequency

High frequency ultrasound measurements on a translucent thin bioglass, based on Si, Ca, Na: Study of the distribution of elastic modulus

2013 ◽  
Vol 36 (1) ◽  
pp. 75-79 ◽  
Author(s):  
Ahmed Bachar ◽  
Georges Nassar ◽  
Cyrille Mercier ◽  
Franck Bouchart ◽  
Claudine Follet ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
High Frequency ◽  
High Frequency Ultrasound ◽  
Ultrasound Measurements ◽  
Frequency Ultrasound

Rock-physics models for heterogeneous creeping rocks and viscous fluids

Geophysics ◽  
2016 ◽  
Vol 81 (4) ◽  
pp. D427-D440 ◽  
Author(s):  
Gary Mavko ◽  
Nishank Saxena
Keyword(s):  
Elastic Modulus ◽  
High Frequency ◽  
Effective Viscosity ◽  
Rock Physics ◽  
Viscous Fluids ◽  
Small Scale ◽  
Creep Function ◽  
Measurement Scales ◽  
Symmetry Direction ◽  
Elastic Inclusions

Rock-physics models are used to explore how small-scale heterogeneity can affect the larger scale viscoelasticity of rocks. Applications include mixtures of creeping clay and elastic quartz, mixtures of different creeping materials (e.g., clay and kerogen), or viscous fluids containing bubbles or solid fines. We have found that elastic inclusions in a Maxwell viscoelastic background change the effective viscosity and the high-frequency limiting elastic modulus. The viscosity response was similar to that observed for a Newtonian fluid, and the high-frequency elastic modulus varied as predicted by elastic effective media models. The characteristic frequency of the effective medium scales with the ratio of effective modulus and effective viscosity. Inclusions also distribute the relaxation times, converting the Maxwell material to resemble a Cole-Cole material. Elastic inclusions in a creeping background decrease the effective viscoelastic Poisson’s ratio of the composite. As with elastic media, geometric alignment of phases with contrasting properties leads to viscoelastic anisotropy. Our modeling has illustrated how the amount of heterogeneity and the microgeometry of heterogeneity affects anisotropy; for example, aligned oblate elastic inclusions can increase the amount of creep in the symmetry direction while decreasing creep normal to the symmetry direction. We have developed a suggested interpretation template for how creep function parameters vary with the amount and microgeometry of elastic phases. Interpretation also depends strongly on the material properties of the creeping phase in the absence of elastic inclusions. Extrapolating from dynamic to quasi-static viscoelastic response is intrinsically nonunique without knowledge of the material microstructure. Dominant relaxation mechanisms can be different at different measurement scales and at different measurement strain amplitudes. For example, the observed dynamic response can be fit with an infinite number of microgeometries, each of which has a different long-term behavior.

Spatially Dependent Mechanical Properties Of Rat Whiskers For Tactile Sensing

2004 ◽  
Vol 841 ◽  
Author(s):  
E. K. Herzog ◽  
D. F. Bahr ◽  
C. D. Richards ◽  
R. F. Richards ◽  
D. M. Rector
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Physical Properties ◽  
Cross Section ◽  
High Frequency ◽  
Tactile Sensing ◽  
Biologically Inspired ◽  
Frequency Information ◽  
Solid Objects ◽  
New Generation

ABSTRACTA new generation of sensors based on biologically inspired whisking action will help determine the presence and location of solid objects and fluid vortices similar to mechanisms used by whisker bearing animals such as rats and seals. By using nanoindentation, we demonstrate that mechanical properties are essentially uniform by cross section, but vary longitudinally from the whisker base (a 3.9 GPa elastic modulus) to the tip (a 3.1 GPa elastic modulus). Several recent studies show propagation of high frequency information through whiskers that are tuned by their physical properties. In order to fully understand and model these properties, this study demonstrates a more complex whisker structure than previously assumed.

Spatially Dependent Mechanical Properties Of Rat Whiskers For Tactile Sensing

2004 ◽  
Vol 844 ◽  
Author(s):  
E. K. Herzog ◽  
D. F. Bahr ◽  
C. D. Richards ◽  
R. F. Richards ◽  
D. M. Rector
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Physical Properties ◽  
Cross Section ◽  
High Frequency ◽  
Tactile Sensing ◽  
Biologically Inspired ◽  
Frequency Information ◽  
Solid Objects ◽  
New Generation

ABSTRACTA new generation of sensors based on biologically inspired whisking action will help determine the presence and location of solid objects and fluid vortices similar to mechanisms used by whisker bearing animals such as rats and seals. By using nanoindentation, we demonstrate that mechanical properties are essentially uniform by cross section, but vary longitudinally from the whisker base (a 3.9 GPa elastic modulus) to the tip (a 3.1 GPa elastic modulus). Several recent studies show propagation of high frequency information through whiskers that are tuned by their physical properties. In order to fully understand and model these properties, this study demonstrates a more complex whisker structure than previously assumed.

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