19.—Propagation of Weak Discontinuities in a Layered Hyperelastic Half-space

1976 ◽  
Vol 75 (3) ◽  
pp. 209-221 ◽  
Author(s):  
Erdogan S. Suhubi ◽  
Alan Jeffrey
Keyword(s):  
Half Space ◽  
Reflection Coefficients ◽  
Initial Condition ◽  
One Dimensional ◽  
Transmission And Reflection Coefficients ◽  
Weak Discontinuities ◽  
Acceleration Waves ◽  
The One ◽  
The Waves ◽  
Transmission And Reflection

SYNOPSISThis paper investigates the one-dimensional propagation of weak discontinuities, that is acceleration waves, in a homogeneous and isotropic half-space composed of an arbitrary number of non-linearly hyperelastic layers. The transmission and reflection coefficients are evaluated in terms of the initial condition at the boundary, and the steepening of the waves to form a shock is discussed. The results are specialised to the case of periodic layering.

Influence of concrete age on the behavior of ultrasonic waves in interfaces (concrete–steel–concrete)

2020 ◽  
Vol 234 (21) ◽  
pp. 4239-4257
Author(s):  
Y Raach ◽  
Y Derouiche ◽  
F Messelmi
Keyword(s):  
Multilayer Structure ◽  
High Performance ◽  
High Performance Concrete ◽  
Plane Waves ◽  
Ultrasonic Waves ◽  
Reflection Coefficients ◽  
Angle Of Incidence ◽  
Transmission And Reflection Coefficients ◽  
The Waves ◽  
Transmission And Reflection

This paper presents the influence of the composite age on the variation of the transmission and reflection coefficients. The composite is the concrete in our case. The studied structure is a multilayer structure composed of two elastic and isotropic layers where each one is characterized by its own physical properties. The problem is simplified in two-dimensional plane waves, and the influence of the attack angle on the acoustic impedances is also examined. Moreover, an experimental study is realized in the formulation of concrete and the measurement of waves propagation velocity. In this work, during the concrete formulation, three different types of concrete were developed: sand concrete, ordinary concrete, and high-performance concrete. The results of simulation and experiments demonstrate that the age of concrete and the internal concrete structure have a direct influence on the evolution of the acoustic parameters as well as the angle of incidence, which has considerably changed the behavior of the transmission and reflection coefficients. This internal structure is directly related to the age of the concrete where its maturity is not reached until after a certain age, which influences the behavior of the waves through the layers of the multilayer structure.

Transmission of Rayleigh waves past a step change in elevation

1965 ◽  
Vol 55 (2) ◽  
pp. 319-334 ◽  
Author(s):  
A. K. Mal ◽  
L. Knopoff
Keyword(s):  
Surface Waves ◽  
Half Space ◽  
Green's Function ◽  
Rayleigh Waves ◽  
Function Method ◽  
Step Change ◽  
Reflection Coefficients ◽  
Homogeneous Half Space ◽  
Transmission And Reflection Coefficients ◽  
Transmission And Reflection

Abstract Using a Green's function method of approximation, transmission and reflection coefficients are computed for the problem of Rayleigh waves incident upon a step change in the elevation of the surface of a homogeneous half-space. Several versions of these approximations are given, differing principally by the method in which the surface waves on the vertical face of the step are taken into account.

Exact and Glauber amplitudes in multi-channel scattering

1979 ◽  
Vol 57 (11) ◽  
pp. 1952-1958 ◽  
Author(s):  
W. van Dijk ◽  
M. Razavy
Keyword(s):  
Composite System ◽  
Numerical Solutions ◽  
Particle System ◽  
Reflection Coefficients ◽  
One Dimensional ◽  
First Order ◽  
Transmission Coefficients ◽  
Transmission And Reflection Coefficients ◽  
Invariant Embedding ◽  
Transmission And Reflection

A model for one-dimensional many-channel scattering of a particle from a composite system is considered. It is assumed that the target cannot break up. Using Bellman's method of invariant embedding, a system of non-linear first-order differential equations with one-point boundary conditions is obtained for the transmission and reflection coefficients. These equations have stable numerical solutions. An alternative invariant embedding with the approximation of no reflection at any stage of the scattering process yields the Glauber approximation for the transmission coefficients. These formulations are used to compare the exact and the Glauber amplitudes for a projectile scattering from a bound two-particle system. It is found that unlike the inelastic Glauber amplitudes, the elastic Glauber amplitudes are very good approximations to the exact results.

scholarly journals Transmission, Reflection and Dissipation of Microwaves in Magnetic Composites with Nanocrystalline Finemet-Type Flakes

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3499
Author(s):  
Anatoly B. Rinkevich ◽  
Dmitry V. Perov ◽  
Yuriy I. Ryabkov
Keyword(s):  
Composite Material ◽  
Microwave Absorption ◽  
Nanocrystalline Alloy ◽  
Reflection Coefficients ◽  
Magnetic Composites ◽  
Transmission And Reflection Coefficients ◽  
Wave Interference ◽  
Microwave Losses ◽  
Frequency Dependences ◽  
Transmission And Reflection

The microwave properties of a composite material containing flakes of finemet-type nanocrystalline alloy placed in the epoxy matrix have been investigated. Two compositions have been studied: with 15% and 30% flakes. Frequency dependences of transmission and reflection coefficients are measured in the frequency range from 12 to 38 GHz. The dielectric permittivity and magnetic permeability are obtained, and the microwave losses are calculated. The dependences of transmission and reflection coefficients have been drawn as functions of wave frequency and thickness of the composite material, taking into account the frequency dependences of permittivity and permeability. The regions of maximal and minimal microwave absorption have been defined. The influence of wave interference on the frequency dependence of microwave absorption is studied.

scholarly journals Сlassical solution of the mixed problem for the one-dimensional wave equation with the nonsmooth second initial condition

2020 ◽  
Vol 64 (6) ◽  
pp. 657-662
Author(s):  
V. I. Korzyuk ◽  
J. V. Rudzko
Keyword(s):  
Boundary Condition ◽  
Wave Equation ◽  
Mixed Problem ◽  
Method Of Characteristics ◽  
Smooth Boundary ◽  
Analytical Form ◽  
Initial Condition ◽  
One Dimensional ◽  
The One ◽  
Dimensional Wave

In this article, we study the classical solution of the mixed problem in a quarter of a plane and a half-plane for a one-dimensional wave equation. On the bottom of the boundary, Cauchy conditions are specified, and the second of them has a discontinuity of the first kind at one point. Smooth boundary condition is set at the side boundary. The solution is built using the method of characteristics in an explicit analytical form. Uniqueness is proved and conditions are established under which a piecewise-smooth solution exists. The problem with linking conditions is considered.

DKP equation with smooth barrier

2021 ◽  
Author(s):  
O. Langueur ◽  
M. Merad ◽  
A. Rassoul
Keyword(s):  
Hypergeometric Function ◽  
Numerical Study ◽  
Confluent Hypergeometric Function ◽  
Reflection Coefficients ◽  
Step Potential ◽  
Dkp Equation ◽  
Transmission And Reflection Coefficients ◽  
Special Cases ◽  
Rectangular Barrier ◽  
Transmission And Reflection

In this paper, we study the Duffin–Kemmer–Petiau (DKP) equation in the presence of a smooth barrier in dimensions space–time (1+1) dimensions. The eigenfunctions are determined in terms of the confluent hypergeometric function [Formula: see text]. The transmission and reflection coefficients are calculated, special cases as a rectangular barrier and step potential are analyzed. A numerical study is presented for the transmission and reflection coefficients graphs for some values of the parameters [Formula: see text] are plotted.

Materials Evaluation and Environmental Monitoring Utilizing an Acoustic Resonance

2020 ◽  
Author(s):  
Hironori Tohmyoh
Keyword(s):  
Resonant Frequency ◽  
Environmental Monitoring ◽  
Water Film ◽  
Acoustic Resonance ◽  
Acoustic Properties ◽  
Reflection Coefficients ◽  
Plate Interface ◽  
Transmission And Reflection Coefficients ◽  
Transmission And Reflection ◽  
Outer Environment

Abstract This paper presents the materials evaluation and environmental monitoring techniques utilizing the acoustic resonance, which have been developed by the authors. When the ultrasound passes through thin layer, the transmission and reflection coefficients take their maximum and the minimum values at the resonant frequency. We call this acoustic resonance. The acoustic properties of a polymer film, e.g., the acoustic impedance, ultrasonic velocity, and density, can be determined by observing the acoustic resonance, which occurs at the water/film/reflection plate interface. Acoustic resonance occurs at the reflection plate/film/outer environment interface sensitively changes depending on the outer environment. With use of this, the temperature of the water as an outer environment is tried to be monitored.

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