Shear wave attenuation and micro-fluidics in water-saturated sand and glass beads

2014 ◽  
Vol 135 (6) ◽  
pp. 3264-3279 ◽  
Author(s):  
Nicholas P. Chotiros ◽  
Marcia J. Isakson
Geophysics ◽  
1990 ◽  
Vol 55 (6) ◽  
pp. 712-722 ◽  
Author(s):  
D. Vo‐Thanh

Measurements of shear wave velocity and attenuation as a function of temperature were made in the kilohertz frequency range in sandstones saturated with various liquids. For sandstones partially saturated with glycerol, two attenuation peaks are observed between −80°C and 100°C; they are attributed to viscous shear relaxation and squirt flow. For fully water‐saturated Berea sandstone, the attenuation decreases as the crack density increases. The displacement of the squirt peak, caused by the increase of the central aspect ratio of cracks, is at the origin of this decrease. A simple viscoelastic model, based on the model of O’Connell and Budiansky using a Cole‐Cole distribution of cracks, is proposed for calculation of the shear modulus of fluid‐saturated rocks. This model interprets the experimental data satisfactorily. The data suggest that the shear attenuation and velocity are controlled by the distribution of crack aspect ratios.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guillaume Flé ◽  
Guillaume Gilbert ◽  
Pol Grasland-Mongrain ◽  
Guy Cloutier

AbstractQuantitative mechanical properties of biological tissues can be mapped using the shear wave elastography technique. This technology has demonstrated a great potential in various organs but shows a limit due to wave attenuation in biological tissues. An option to overcome the inherent loss in shear wave magnitude along the propagation pathway may be to stimulate tissues closer to regions of interest using alternative motion generation techniques. The present study investigated the feasibility of generating shear waves by applying a Lorentz force directly to tissue mimicking samples for magnetic resonance elastography applications. This was done by combining an electrical current with the strong magnetic field of a clinical MRI scanner. The Local Frequency Estimation method was used to assess the real value of the shear modulus of tested phantoms from Lorentz force induced motion. Finite elements modeling of reported experiments showed a consistent behavior but featured wavelengths larger than measured ones. Results suggest the feasibility of a magnetic resonance elastography technique based on the Lorentz force to produce an shear wave source.


2015 ◽  
Vol 529 ◽  
pp. 182-190 ◽  
Author(s):  
Xinyao Yang ◽  
Ziyi Yin ◽  
Fangmin Chen ◽  
Jingjing Hu ◽  
Yuesuo Yang

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