scholarly journals Measurement of the flexural wave power transmission and reflection coefficients of joints using wave‐number domain methods

1995 ◽  
Vol 97 (5) ◽  
pp. 3331-3331
Author(s):  
Robert J. Unglenieks ◽  
Robert J. Bernhard
Keyword(s):  
Power Transmission ◽  
Wave Number ◽  
Flexural Wave ◽  
Reflection Coefficients ◽  
Wave Power ◽  
Transmission And Reflection Coefficients ◽  
Transmission And Reflection

Power Flow Analysis of Beam Members With Multiple Wave Types

1995 ◽  
Author(s):  
Albert L. Stiehl
Keyword(s):  
Finite Element ◽  
Power Flow ◽  
Power Transmission ◽  
Power Level ◽  
Flow Analysis ◽  
Reflection Coefficients ◽  
Multiple Wave ◽  
Power Flow Analysis ◽  
Transmission And Reflection Coefficients ◽  
Transmission And Reflection

Abstract A power flow finite element method (PFFEM) is developed in Reference 1 for the steady state high frequency vibration analysis of beams in which there is propagation of one wave type (bending). A finite element thermal analog presented herein for power flow analysis of beam members in which both bending and longitudinal waves are present is a farther development of the PFFEM. Conducting bar elements model power flow in the beam and also power transmission, reflection and conversion at structural joints. Convection elements model internal power dissipation. Properties of joint elements are in general non-linear and depend upon the power level at the joint as well as transmission and reflection coefficients. The thermal analog is verified for particular linear cases wherein properties of the joint elements are dependent only upon the transmission and reflection coefficients.

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.

Damage Assessment of Beams Using Flexural Wave Reflection Coefficients

2007 ◽  
Vol 347 ◽  
pp. 193-198 ◽  
Author(s):  
Simon P. Shone ◽  
Brian R. Mace ◽  
Tim P. Waters
Keyword(s):  
Damage Assessment ◽  
Wave Reflection ◽  
Experimental Results ◽  
Flexural Wave ◽  
Reflection Coefficients ◽  
Wave Power ◽  
Spring Model ◽  
Low Frequencies ◽  
Experimental Errors ◽  
Ill Conditioning

The wave reflection coefficients of damage such as cracks, notches and slots in otherwise uniform beams depend on frequency and on the size of the damage. Experimental results are presented for the wave power reflection coefficients of transverse slots of various depths sawn into a number of beam specimens. These results are compared with a conventional spring model to estimate the depth of the slot. The method appears to work well for larger slot depths (greater than about 30% of the thickness of the beam) and at higher frequencies, allowing their existence to be inferred and their size to be estimated. This is due to the fact that the reflection coefficients are larger in these regimes. For smaller slots or at low frequencies, noise and experimental errors, such as miscalibration errors and ill-conditioning, become more significant.

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.

scholarly journals Study of superradiance in the Lambert-W potential barrier

2019 ◽  
Vol 34 (16) ◽  
pp. 1950087 ◽  
Author(s):  
Luis Puente ◽  
Carlos Cocha ◽  
Clara Rojas
Keyword(s):  
Reflection Coefficient ◽  
Potential Barrier ◽  
Gordon Equation ◽  
Reflection Coefficients ◽  
Hyperbolic Tangent ◽  
Step Potential ◽  
Transmission And Reflection Coefficients ◽  
Klein Gordon ◽  
Klein Gordon Equation ◽  
Transmission And Reflection

We present a new potential barrier that presents the phenomenon of superradiance when the reflection coefficient [Formula: see text] is greater than one. We calculated the transmission and reflection coefficients for three different regions. The results are compared with those obtained for the hyperbolic tangent potential barrier and the step potential barrier. We also present the solution of the Klein–Gordon equation with the Lambert-[Formula: see text] potential barrier in terms of the Heun Confluent functions.

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