Anisotropy of ultrasonic waves propagation velocities in CdHgTe/CdTe

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.

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Determination of Ultrasonic Waves’ Propagation Angles for the Numerical Reconstruction of Thermite Welding Rail's Defects

International Review on Modelling and Simulations (IREMOS) ◽

10.15866/iremos.v9i5.10056 ◽

2016 ◽

Vol 9 (6) ◽

pp. 450

Author(s):

Oussama Bouazaoui ◽

Abdelkrim Chouaf

Keyword(s):

Ultrasonic Waves ◽

Numerical Reconstruction ◽

Waves Propagation

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Behavior of ultrasonic waves in wood with presence of holes

CERNE ◽

10.1590/s0104-77602012000300019 ◽

2012 ◽

Vol 18 (3) ◽

pp. 507-514 ◽

Cited By ~ 2

Author(s):

Chiara Barros Secco ◽

Raquel Gonçalves ◽

Domingos Guilherme Pelegrino Cerri ◽

Érica Caroline Vasques ◽

Fernando Augusto Franco Batista

Keyword(s):

Linear Model ◽

Circular Hole ◽

Empty Space ◽

Ultrasonic Waves ◽

Velocity Reduction ◽

Hollow Space ◽

Wave Path ◽

Pattern Of Variation ◽

Propagation Velocities

This work aimed to analyze the pattern of variation in wave lengths in presence of wood holes and to develop a model capable of describing the process. To attain that end, wood pieces were used from species pequiá (Aspidosperma desmanthum), on which circular and linear artificial holes were made and gradually enlarged. Ultrasonic tests were performed using USLab equipment and 45 kHz transducers. Measurements were taken first on the intact piece and then after each stage of artificial hole enlargement. Results demonstrated that propagation velocities of ultrasonic waves are affected by presence of holes and also that reduction in velocity is caused by changes in wave path, since waves tend to deviate from empty space and travel through matter. The circular hole type had a slightly stronger influence on velocity reduction than the linear hole type. Variation in velocity as a function of increasing percentage of hollow space relative to the intact piece can be represented by a linear model.

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