Simulation and Experimental Measurement of Ultrasonic Waves Propagation Velocity in Trabecular Bone

2011 ◽  
Vol 418-420 ◽  
pp. 765-771
Author(s):  
Abderrazek Bennamane ◽  
Tarek Boutkedjirt
Keyword(s):  
Porous Media ◽  
Trabecular Bone ◽  
Interstitial Fluid ◽  
Ultrasonic Waves ◽  
Longitudinal Waves ◽  
Fluid Saturation ◽  
Waves Propagation ◽  
Propagation Velocities ◽  
Rigid Skeleton

The influence of porosity on ultrasonic waves propagation in porous media, specifically in the bone tissue is examined in this work. The tissue is considered as a complex medium (anisotropic and heterogeneous) made of a rigid skeleton, filled by a medium which is supposed to be fluid. The theory of Biot is well suitable to describe the behavior of the ultrasonic waves in this tissue. The aim of this work is to determine how porosity affects propagation velocities of the various waves susceptible to propagate through the cortical or trabecular bone. By reference to this model and taking account of the viscous dissipation of the interstitial fluid, various propagation velocities were determined. A range of porosity extending from 0 to 1 and two types of fluid saturation (water and marrow) was considered. The results obtained show the influence of porosity on the propagation velocities of the longitudinal waves (the slow and the fast one) as well as of the transverse wave. Porosity and the nature of the interstitial fluid affect the dissipation phenomenon. According to the model suggested in this study and to the experimental results obtained, it can be affirmed that the determination of various propagation velocities in the bone leads to its characterization and can inform us about its pathological status.

On Differences of Statically and Dynamically Determined Elastic Modules of Materials Like Trabecular Bone

2007 ◽  
Author(s):  
D. H. Besdo ◽  
S. Besdo
Keyword(s):  
Trabecular Bone ◽  
Cross Sections ◽  
Step Function ◽  
Shear Mode ◽  
Variable Cross ◽  
Half Cycle ◽  
Longitudinal Waves ◽  
Ultrasonic Methods ◽  
Elastic Modules

The linear elastic material law which is usually applied in simulations of bone behavior reads σij = Cijkl εkl. It contains up to 21 independent constants. In most applications only nine constants (orthotropic behavior) are used. The determination of these constants is troublesome. The most applied experimental method is based on ultrasonic wave propagation. As it is often recognized the elastic modules measured by this method differ significantly from those found by static testing. Whereas Young’s modules differ slightly only, the determination of shear modules by ultrasonic methods is extremely doubtful, especially in trabecular bone. To find reasons for this effect, wave propagations are simulated by Finite-Element-techniques. This is done for artificial structures and also for realistic models of trabecular bone based one μCT-data. It can be recognized that in structured media always three types of waves propagate through the material with different speeds. Unfortunately the shear wave which is to be measured is the slowest one. Even if no longitudinal waves disturb the measurements, at least bending waves appear and pretend some kind of shear mode. The different orientations of the trabeculae can cause longitudinal waves when shear waves are applied. The stimulation of the ultrasound is at first simulated as a half cycle or as a step function only. The realistic waves are superimpositions of several of such motions. Such a relatively simple simulation makes possible to distinguish the three wave types mentioned above. The superimpositions complicate the motion extremely. Also reflection, damping and variable cross sections make it almost impossible to identify the modules, especially the shear modules, in a certain manner.

The Frequency-Domain Algorithm for Ultrasonic Imaging of Complex-Shaped Objects

2018 ◽  
Vol 769 ◽  
pp. 262-268
Author(s):  
Dmitry Dolmatov ◽  
Dmitriy A. Sednev ◽  
Roman Pinchuk
Keyword(s):  
Frequency Domain ◽  
Ultrasonic Imaging ◽  
Ultrasonic Waves ◽  
Synthetic Aperture ◽  
The Novel ◽  
Suggested Technique ◽  
Waves Propagation ◽  
Synthetic Aperture Focusing ◽  
Synthetic Aperture Focusing Technique

The algorithms based on Synthetic Aperture Focusing Technique are aimed at the determination of the imageries of the flaws in controlled objects. Ultrasonic imaging of complex-shaped objects requires specific algorithms which are able to take into account the complicated character of ultrasonic waves propagation. In this article, we suggested the novel frequency-domain algorithm for ultrasonic imaging of complex-shaped objects. This algorithm is based on Phase –shift migration theory and Stolt transform. The evaluation of suggested technique was done by the application of raw ultrasonic data which was obtained by using computer simulations. Derived results show that proposed algorithm is able to make accurate and precise imaging of flaws in complex-shaped objects.

Determination of the foaming parameters of polyurethane compositions from the velocity of longitudinal ultrasonic waves

1979 ◽  
Vol 15 (3) ◽  
pp. 316-317 ◽  
Author(s):  
V. M. Mel'nikov ◽  
�. A. Putnin'sh ◽  
V. O. Putninya ◽  
V. P. Karlivan
Keyword(s):  
Ultrasonic Waves ◽  
Longitudinal Ultrasonic Waves

Mathematical Formulation of the Global Coefficients of Transmission and Reflection of Ultrasonic Waves in Bi-Phase Porous Medium

2015 ◽  
Vol 1101 ◽  
pp. 471-479
Author(s):  
Georges Freiha ◽  
Hiba Othman ◽  
Michel Owayjan
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Wave Propagation ◽  
Mathematical Formulation ◽  
Ultrasonic Waves ◽  
Ultrasonic Wave Propagation ◽  
Local Coefficients ◽  
Important Field ◽  
New Formulation ◽  
Transmission And Reflection

The study of signals propagation inside porous media is an important field especially in the biomedical research related to compact bones. The purpose of this paper is to determine a mathematical formulation of the global coefficients of transmission and reflection of nondestructive ultrasonic waves in any bi-phase porous medium. Local coefficients of transmission and reflection on the interface of the porous medium will be determined based on a study of boundary conditions. The behavior of different waves inside the porous medium will be developed so that we can derive a new formulation of global coefficients that takes interior phenomena into consideration. Results are found independently of the geometrical and physical characteristics of the medium. Note that this study is based on normal incident ultrasonic wave propagation.

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