Ondes electromagnétiques de surface en géométrie cylindrique. Les modes de révolution d'ordre supérieur

1985 ◽  
Vol 63 (5) ◽  
pp. 567-573
Author(s):  
G. Zepp ◽  
A. Wick ◽  
G. Ritoux ◽  
G. Fabre ◽  
M. Billaud
Keyword(s):  
Surface Wave ◽  
Attenuation Factor ◽  
High Order ◽  
Cross Sectional ◽  
Electromagnetic Surface Wave ◽  
Metallic Cylinder ◽  
Analytical Expressions ◽  
Wave Modes ◽  
The Revolution

We have studied the revolution electromagnetic surface wave modes of high order (TM, TE) propagating at the surface of a circular cross-sectional metallic cylinder coated with two dielectrics. We have determined precise analytical expressions of attenuation factor and power localization ratio.

Propagation d'une onde électromagnétique à la surface d'un conducteur ou d'un supraconducteur de section circulaire

1981 ◽  
Vol 59 (7) ◽  
pp. 902-913 ◽  
Author(s):  
Georges Fabre ◽  
Alain Wick ◽  
Gérard Zepp
Keyword(s):  
Electromagnetic Wave ◽  
Phase Shift ◽  
Cross Section ◽  
Attenuation Factor ◽  
Circular Cross Section ◽  
Transverse Mode ◽  
Onde Électromagnétique ◽  
Mode Propagation ◽  
Metallic Cylinder ◽  
Analytical Expressions

We are studying the electromagnetic wave (magnetic transverse mode) propagation on the surface of a circular cross section metallic cylinder coated with one or several dielectrics. The method we use allows us to study not only the case of ordinary metals, but also the case of superconductor metals. We determine the precise analytical expressions (for any kind of metal) of characteristic quantities: attenuation factor and phase shift.

Modes supérieurs pour un résonateur électromagnétique à ondes de surface

1994 ◽  
Vol 72 (9-10) ◽  
pp. 554-558 ◽  
Author(s):  
M. Billaud ◽  
A. Wick ◽  
G. Ritoux ◽  
G. Zepp
Keyword(s):  
Surface Wave ◽  
Resonant Frequency ◽  
Quality Factor ◽  
Numerical Study ◽  
Transverse Magnetic ◽  
High Order ◽  
Analytical Formulation ◽  
Electromagnetic Surface Wave ◽  
Wave Resonator

The theory of an open electromagnetic surface-wave resonator with two dielectrics is developed. The analytical formulation of results allows easy study of resonant frequency and quality factor for the different transverse magnetic modes. The numerical study shows the interest of high order modes.

Contribution of Lamb wave modes in the formation of higher order modes cluster (HOMC) guided waves

2021 ◽  
pp. 095440622110424
Author(s):  
Z Abbasi ◽  
F Honarvar
Keyword(s):  
Finite Element ◽  
Wave Packet ◽  
Lamb Wave ◽  
Guided Waves ◽  
Element Model ◽  
Higher Order ◽  
Guided Wave ◽  
Cross Sectional ◽  
Higher Order Modes ◽  
Wave Modes

In recent years, Higher Order Modes Cluster (HOMC) guided waves have been considered for ultrasonic testing of plates and pipes. HOMC guided waves consist of higher order Lamb wave modes that travel together as a single nondispersive wave packet. The objective of this paper is to investigate the effect of frequency-thickness value on the contribution of Lamb wave modes in an HOMC guided wave. This is an important issue that has not been thoroughly investigated before. The contribution of each Lamb wave mode in an HOMC guided wave is studied by using a two-dimensional finite element model. The level of contribution of various Lamb wave modes to the wave cluster is verified by using a 2D FFT analysis. The results show that by increasing the frequency-thickness value, the order of contributing modes in the HOMC wave packet increases. The number of modes that comprise a cluster also increases up to a specific frequency-thickness value and then it starts to decrease. Plotting of the cross-sectional displacement patterns along the HOMC guided wave paths confirms the shifting of dominant modes from lower to higher order modes with increase of frequency-thickness value. Experimental measurements conducted on a mild steel plate are used to verify the finite element simulations. The experimental results are found to be in good agreement with simulations and confirm the changes observed in the level of contribution of Lamb wave modes in a wave cluster by changing the frequency-thickness value.

An Analytical Method of Analyzing the Heat Conduction for the Unequal Cross-Section Straight Fin

2013 ◽  
Vol 365-366 ◽  
pp. 1211-1216
Author(s):  
Fan Zhang ◽  
Peng Yun Song
Keyword(s):  
Heat Conduction ◽  
Cross Section ◽  
Analytical Method ◽  
Thermal Analyses ◽  
Cross Sectional ◽  
Cross Section Area ◽  
Section Area ◽  
Calculation Results ◽  
The Cross ◽  
Analytical Expressions

The cross-section area of straight fin is often considered to be equal in the thermal analyses of straight fin, but sometimes it is unequalin actual situation. Taking a straight fin with two unequal cross-sectional areas as an example,an analytical method of heat conduction for unequal section straight fin is presented. The analytical expressions of temperature field and heat dissipating capacity about the fin,which has a smaller cross-section area near the fin base and a larger one, is obtained respectively. The calculation results of the unequal cross-section are fully consistent with the equal area one, so the method is proved right. The results show that the larger the cross section areanear the base,the better is the heat transfer, and the temperature at the base with larger cross-section area is lower than that with smaller cross-section area when the amount of heat is fixed.

Three-Dimensional Solutions for Rotor Blades Using High-Order Geometrical Nonlinear Beam Finite Elements

2019 ◽  
Vol 64 (3) ◽  
pp. 1-10
Author(s):  
Matteo Filippi ◽  
Alfonso Pagani ◽  
Erasmo Carrera
Keyword(s):  
Finite Elements ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Shear Deformation Theory ◽  
High Order ◽  
Rotor Blades ◽  
Constitutive Law ◽  
Displacement Fields ◽  
Cross Sectional ◽  
The Cross

This paper proposes a geometrically nonlinear three-dimensional formalism for the static and dynamic study of rotor blades. The structures are modeled using high-order beam finite elements whose kinematics are input parameters of the analysis. The displacement fields are written using two-dimensional Taylor- and Lagrange-like expansions of the cross-sectional coordinates. As far as the Taylor-like polynomials are concerned, the linear case is similar to the first-order shear deformation theory, whereas the higher-order expansions include additional contributions that describe the warping of the cross section. The Lagrange-type kinematics instead utilizes the displacements of certain physical points as degrees of freedom. The inherent three-dimensional nature of the Carrera unified formulation enables one to include all Green–Lagrange strain components as well as all coupling effects due to the geometrical features and the three-dimensional constitutive law. A number of test cases are considered to compare the current solutions with experimental and theoretical results reported in terms of large deflections/rotations and frequencies related to small amplitude vibrations.

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