Energy Partition of Harmonic Waves through a Micro Gap

2011 ◽  
Vol 66-68 ◽  
pp. 1428-1433
Author(s):  
Xiao Yun Chen ◽  
Gui Lan Yu
Keyword(s):  
Incident Angle ◽  
Superposition Method ◽  
Harmonic Waves ◽  
Algebraic Equations ◽  
Energy Partition ◽  
Analysis Technique ◽  
Nonlinear Boundary Problem ◽  
Fourier Analysis Technique ◽  
Incident Waves ◽  
Gap Width

Energy partition of harmonic waves through a micro gap considering frictional contact was investigated. The incident waves were assumed to be strong enough to make the two solids come into contact. Using the Fourier analysis technique and corrective solution superposition method, the nonlinear boundary problem was reduced to a set of algebraic equations. Special examples for identical materials were discussed in detail. The locations and extents of the separation, slip and stick zones and the energy partition are displayed. Moreover, the effects of gap width, coefficients of friction and incident angle are discussed. These relations are quite effective on seismology and civil engineering.

Influences of an Initial Micro Gap on Wave Transmission

2010 ◽  
Vol 29-32 ◽  
pp. 2662-2667
Author(s):  
Xiao Yun Chen ◽  
Gui Lan Yu
Keyword(s):  
Elastic Waves ◽  
Frictional Contact ◽  
Superposition Method ◽  
Energy Partition ◽  
Non Destructive Evaluation ◽  
Analysis Technique ◽  
Fourier Analysis Technique ◽  
Propagation Of Elastic Waves ◽  
Non Destructive ◽  
Gap Width

The propagation of elastic waves through a micro gap considering frictional contact is investigated in the present paper. Using the Fourier analysis technique and corrective solution superposition method, the problem is solved analytically. Special examples for identical materials are discussed in detail. The results show that the initial gap width has significant influences on the harmonics and energy partition and their relations may be effective on non-destructive evaluation of a pre-existing gap.

Cosserat Spectrum of an Axisymmetric Elasticity Problem for a Finite-Length Solid Cylinder

2018 ◽  
Vol 35 (3) ◽  
pp. 343-349
Author(s):  
Yu. V. Tokovyy
Keyword(s):  
Asymptotic Behavior ◽  
Finite Length ◽  
Solution Method ◽  
Superposition Method ◽  
Algebraic Equations ◽  
Solid Cylinder ◽  
Cosserat Spectrum ◽  
Linear Algebraic Equations ◽  
Key Features ◽  
Axisymmetric Elasticity

ABSTRACTAn algorithm for the computation and analysis of the Cosserat spectrum for an axisymmetric elasticity boundary-value problem in a finite-length solid cylinder with boundary conditions in terms of stresses is proposed. By making use of the cross-wise superposition method, the spectral problem is reduced to systems of linear algebraic equations. A solution method for the mentioned systems is presented and the asymptotic behavior of the Cosserat eigenvalues is established. On this basis, the key features of the Cosserat spectrum for the mentioned problem are analyzed with special attention given to the effect of the cylinder aspect ratio.

Sizing Detection of a Surface-Breaking Crack by Ultrasonic Technique

2011 ◽  
Vol 52-54 ◽  
pp. 865-868 ◽  
Author(s):  
Shiuh Chuan Her ◽  
Sheng Tung Lin
Keyword(s):  
Test Specimen ◽  
Incident Angle ◽  
Ultrasonic Technique ◽  
Non Destructive Evaluation ◽  
Different Depths ◽  
Crack Sizing ◽  
Incident Waves ◽  
Surface Breaking Crack ◽  
Pulse Echo ◽  
Non Destructive

Ultrasonic is one of the most common uses of non-destructive evaluation technique. It could detect flaws inside the structure and on the surface such as voids, holes and cracks. In this investigation, a 304 steel block with a surface-breaking crack was fabricated. A series of test specimen with different depths of surface-breaking crack ranging from 2mm to 9mm was fabricated. The depth of the surface crack was evaluated by the pulse-echo ultrasonic technique. In this work, 2.25MHz, 5MHz and 10MHz of incident waves were employed to detect the depth of the surface-breaking crack. The effect of incident angle on the measuring accuracy was investigated. Experimental results showed that the accuracy of crack sizing detection by ultrasonic technique is not only dependent on the frequency of the incident wave but also dependent on the incident angle.

An In Situ XRD Technique For Annealing Investigations

1994 ◽  
Vol 38 ◽  
pp. 757-762
Author(s):  
D.E. Koylman ◽  
S.C. Axtel ◽  
B.W. Robertson
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
Copper Powder ◽  
Diffraction Data ◽  
Particle Growth ◽  
Annealing Behavior ◽  
In Situ Xrd ◽  
Analysis Technique ◽  
Fourier Analysis Technique

Abstract An in situ XRD technique employing a diffractometer equipped with a high temperature camera was used to investigate the annealing behavior of nanoerystalline copper powder produced by mechanical milling. Specimens were annealed isothermally for 12 h at temperatures between 480 and 770 K. The diffraction data was analyzed using a single-profile Fourier analysis technique. The activation energy for diffracting particle growth was determined to be 0.45 eV/atom.

Model Experiments of Floating Side-by-Side Barges

2019 ◽  
Author(s):  
Kie Hian Chua ◽  
Pedro Cardozo de Mello ◽  
Kazuo Nishimoto ◽  
Yoo Sang Choo
Keyword(s):  
Numerical Models ◽  
Wave Excitation ◽  
Flow Models ◽  
Model Experiments ◽  
Dissipative Effects ◽  
Wave Elevation ◽  
Wave Heights ◽  
Wave Conditions ◽  
Incident Waves ◽  
Gap Width

Abstract The interaction between two floating vessels has been a subject of much study in recent years due to its relevance to floating liquefied natural gas (FLNG) developments. The safety and operability of these facilities are directly influenced by the wave elevation in the gap between the two vessels as well as the relative motions between the vessels. In the industry, it is common practice to use potential flow models to calculate free-surface responses under various wave conditions. Given that these numerical models are inviscid, calibration of additional damping terms are usually carried out using model tests to in order to account for the viscous dissipation on the gap hydrodynamics. However, it is known that the dissipative effects of viscosity may be nonlinear and thus, model test data obtained using one set of wave conditions may not be suitable for use in another scenario. In this paper, model experiments of two identical side-by-side barges of 280m (length) × 46m (breadth) × 16.5m (draught) under various wave excitation are described. The experiments considered a range of parameters such as gap width, wave heights, periods and wave directions. The results obtained for each set of these parameters are discussed and compared between the two types of incident waves (regular and irregular).

Preparation and Optical Properties of One-Dimensional Ag/SiOx Photonic Crystal

2014 ◽  
Vol 576 ◽  
pp. 27-31
Author(s):  
Gai Mei Zhang ◽  
Can Wang ◽  
Yan Jun Guo ◽  
Wang Wei ◽  
Xiao Xiang Song
Keyword(s):  
Photonic Crystal ◽  
Band Gap ◽  
Electromagnetic Waves ◽  
Photonic Band Gap ◽  
Incident Angle ◽  
One Dimensional ◽  
The One ◽  
Photonic Band ◽  
Gap Width ◽  
Band Gap Width

The photonic crystal has the property that electromagnetic waves with interval of frequency in photonic band gap (PBG) can not be propagated, so it has important applying and researching value. The traditional one-dimensional photonic crystal is with narrow band gap width, and the reflection within the band is small, especially the band gap is sensitive to the incident angle and the polarization of light. A new photonic band gap (PBG) structure, metallodielectric photonic crystal by inserting metal film in the medium can overcomes the shortcomings mentioned above. The one-dimensional Ag/SiOx photonic crystal was prepared, and theoretical and experimental researches were developed. The results show that photonic band gap appears gradually and the band gap width increase with increasing of period of repeating thickness. With the thickness of Ag film increasing, the band gap width increases, but the starting wavelength of the photonic band gap keeps unchanged. With thickness of SiOx film increasing, the band gap width of photonic band gap also increases, but it is not obvious and starting wavelength increases.

scholarly journals Error Estimates for Solutions of the Semilinear Parabolic Equation in Whole Space

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Xiaomei Hu
Keyword(s):  
Parabolic Equation ◽  
Initial Data ◽  
Error Estimates ◽  
Three Dimensional ◽  
Semilinear Parabolic Equation ◽  
Energy Methods ◽  
Analysis Technique ◽  
Whole Space ◽  
Fourier Analysis Technique ◽  
Semilinear Parabolic

This paper is focused on the error estimates for solutions of the three-dimensional semilinear parabolic equation with initial datau0∈L2(ℝ3). Employing the energy methods and Fourier analysis technique, it is proved that the error between the solution of the semilinear parabolic equation and that of linear heat equation has the behavior asO((1+t)−3/8).

Motion at an Explosive Source as Deduced From Surface Waves

1960 ◽  
Vol 31 (1-2) ◽  
pp. 5-17
Author(s):  
Carl Kisslinger
Keyword(s):  
Fourier Analysis ◽  
Vertical Acceleration ◽  
Analysis Method ◽  
Phase Velocities ◽  
The Earth ◽  
Analysis Technique ◽  
Explosive Source ◽  
History Of ◽  
Frequency Components ◽  
Fourier Analysis Technique

Abstract The history of events occurring near the source following a small explosion has been deduced from the Rayleigh waves recorded at two distances. The Fourier analysis method developed by Sato, and Lamb’s solution for the displacement on a half-space have been employed in two distinct approaches to this problem. The displacement history from the first approach shows an essentially rectilinear vibration of the earth partiele, following the initial compression. The second technique yields the vertical point force equivalent to the explosion. The vertical acceleration at the source from the first method agrees fairly well in general form with the force found in the second. Information about the phase velocities and the initial phases of the constituent frequency components is a valuable by product of the Fourier analysis technique.

Generation and radiation of third harmonics by s-polarized electromagnetic waves incident on a narrow inhomogeneous magnetoactive plasma layer

1989 ◽  
Vol 41 (1) ◽  
pp. 31-36 ◽  
Author(s):  
A. M. Hussein
Keyword(s):  
Electromagnetic Waves ◽  
Plasma Layer ◽  
Magnetoactive Plasma ◽  
Wave Generation ◽  
Inhomogeneous Layer ◽  
Harmonic Waves ◽  
Third Harmonic ◽  
Unmagnetized Plasma ◽  
Incident Waves ◽  
Inhomogeneous Magnetoactive Plasma

An investigation is made of wave generation and radiation of third harmonics by s-polarized electromagnetic waves incident on a narrow inhomogeneous layer of a magnetoactive plasma. The amplitudes of the radiated third-harmonic waves are calculated. In contrast with second harmonics, third harmonics are radiated for the case of normally incident waves on an unmagnetized plasma.

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