scholarly journals Consistency of students’ conceptions of wave propagation: Findings from a conceptual survey in mechanical waves

2011 ◽  
Vol 7 (2) ◽  
Author(s):  
Apisit Tongchai ◽  
Manjula Devi Sharma ◽  
Ian D. Johnston ◽  
Kwan Arayathanitkul ◽  
Chernchok Soankwan
Keyword(s):  
Wave Propagation ◽  
Mechanical Waves

Damping Effect on Mechanical Waves in an Elastic Solid Expanded Tubular

2006 ◽  
Vol 129 (4) ◽  
pp. 698-712
Author(s):  
A. Karrech ◽  
A. Seibi ◽  
T. Pervez
Keyword(s):  
Mathematical Model ◽  
Wave Propagation ◽  
Pressure Wave ◽  
Elastic Solid ◽  
Tube System ◽  
Structure Interaction ◽  
Damping Effect ◽  
Elastic Tubes ◽  
Mechanical Waves ◽  
Critical Regions

The present paper studies the dynamics of submerged expanded elastic tubes due to postexpansion sudden mandrel release known as pop-out phenomenon. A mathematical model describing the dynamics of the borehole-fluid-tube system is presented. Coupling of the fluid-structure interaction and damping effects were taken into consideration. An analytical solution for the displacement, stress, and pressure wave propagation in the fluid-tube system was obtained. The developed model predicted localized critical regions where the structure might experience failure.

Stress anisotropy and wave propagation: a micromechanical view

1996 ◽  
Vol 33 (5) ◽  
pp. 770-782 ◽  
Author(s):  
J C Santamarina ◽  
G Cascante
Keyword(s):  
Wave Propagation ◽  
Polarization Plane ◽  
Mean Stress ◽  
Resonant Column ◽  
Measured Velocity ◽  
Stress Anisotropy ◽  
Mechanical Waves ◽  
The Mean ◽  
Stress Ratios ◽  
Deviatoric Stresses

Wave propagation is a constant-fabric macrophenomenon, suitable to microinterpretation. Both velocity and attenuation characterize state, including inherent and stress-induced anisotropy. The purpose of this research is to study the effect of isotropic and deviatoric stresses on wave propagation in particulate materials at low strains and to interpret results at the microlevel. A resonant-column device was midified to allow for the application of axial extension and axial compression deviatoric loading. The fixed-free boundary condition of the sample was maintained. Data for round, hard-grained sand show that shear wave velocity and attenuation are primarily dependent on the mean stress on the polarization plane, with minimal effect of the deviatoric component, in agreement with prior observations at stress ratios less than 2–3. Attenuation is strongly correlated with the mean stress in the polarization plane and the level of shear strain. Damping does not vanish at low strains, contrary to predictions based on hysteretic behaviour; hence, other loss mechanisms must take place at low strains. Low-strain wave parameters are adequately corrected for mid-strain using modified hyperbolic models. Measured velocity and damping trends during isotropic and anisotropic loading qualitatively agree with predictions based on regular arrays. Key words: mechanical waves, resonant column, damping, shear modulus, stress anisotropy, random vibration.

MECHANISM OF ACOUSTIC WAVE PROPAGATION: A REAL ROLE OF VIRTUAL SOURCES

2001 ◽  
Vol 09 (03) ◽  
pp. 719-730 ◽  
Author(s):  
HENRYK LASOTA
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Plane Wave ◽  
Formal Proof ◽  
Equal Weight ◽  
Acoustic Wave Propagation ◽  
Dirac Delta ◽  
Delta Distribution ◽  
Mechanical Waves

The Huygens problem of self-regeneration of the acoustic wave crossing a liquid medium is discussed in the paper. Equal weight of both elastic and kinetic aspects of mechanical waves in fluids is stressed. Two types of virtual surface sources are defined, reflecting local action of the pressure and particle velocity, respectively. They are applied by the author in calculations of secondary radiation from the wave front of the plane wave. The Dirac delta impulse has been used as a waveform, the wave thus being reduced to its own front. The results have been obtained analytically, thanks to some particularly "friendly" features of the operation of convolution with the delta distribution. The paper gives formal proof to Fresnel's intuitive explanation of the mechanism of the forward-only propagation of the wave with no backward effects.

On the Wave Propagation of Disturbances in Homogeneous Electromechanical Systems

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Kalyan Dasgupta ◽  
Anil M. Kulkarni ◽  
S. A. Soman
Keyword(s):  
Wave Propagation ◽  
Power Systems ◽  
Transport Delay ◽  
System Parameters ◽  
Mass Line ◽  
Lumped Parameter ◽  
Mechanical Waves ◽  
Nonhomogeneous System ◽  
Velocity Of Propagation ◽  
Line Resistance

In this paper, we make an attempt to describe the phenomenon of wave propagation when a disturbance is introduced in an electromechanical system having a lumped parameter representation. We initially discuss mechanical waves in homogeneous spring mass systems and then focus on electromechanical wave propagation in power systems. We primarily discuss ring and open end systems. Eigenvalue analysis of the system is done to find the behavior of the orthogonal modes as a function of time and space. We then derive an expression for velocity of propagation of the disturbance wave and the transport delay associated with it. Effects of system parameters, like generator inertia and transmission line resistance, are also discussed. Although the theory was developed considering homogeneous systems (identical values of inertia/mass, line parameters/spring constant, etc.), an implementation on a nonhomogeneous system is also presented in this paper. Numerical simulations were done and compared with the analytical results derived in this paper.

scholarly journals Analisis Pemahaman Konsep Fisika Peserta Didik dengan Instrumen Four-Tier Diagnotict Test

2019 ◽  
Vol 4 (1) ◽  
pp. 35
Author(s):  
Yuni Sufiani ◽  
Erniwati Erniwati ◽  
Rosliana Eso
Keyword(s):  
Wave Propagation ◽  
Primary Data ◽  
Stationary Waves ◽  
Mechanical Wave ◽  
Average Value ◽  
Descriptive Research ◽  
Test Instrument ◽  
Mechanical Waves ◽  
Quantitative Descriptive ◽  
Level Of Understanding

This study aims to determine the understanding of the concept of students on mechanical wave material for students in class XI SMAN 1 Mawasangka Tengah. This type of research is a type of quantitative descriptive research. In this study, the authors wanted to analyze the students' conceptual understanding using the Four-tier diagnostic test instrument. The object of this research is the students of class XI IPA (1) and XI IPA (2) at SMAN 1 Mawasangka Tengah. The data in this study are primary data collected using four-tier diagnostic tests and documentation. The results of the data analysis showed that the average value of the percentage level of understanding of sub-concept students (1) the factors that influence the speed of the wave propagation, namely 4.4% understanding the concept, 81.4% misconception and 14.2% not understanding the concept (2) The current wave period is 23.5% understanding the concept, 64.4% misconception and 13.1% not understanding the concept (3) The frequency of the traveling wave is 32.2% understanding the concept, 51.4% misconception and 16.4 % do not understand the concept (4) Frequency on stationary waves is 36.6% understand the concept, 48.6% misconception and 14.7% do not understand the concept and (5) Wavelength on stationary waves is 15.8% understand the concept, 69 , 9% had misconceptions and 14.2% did not understand the concept. Based on the results of the analysis, it was concluded that: 1) The students' understanding of the concept of mechanical waves was included in the low category. Students who understood the concept were 22.5%, most of the students' understanding of the criteria did not understand the concept of 14.7% and 62.8% indicated that they had misconceptions. 2) Misconception of the high category found in the concept of factors that affect the speed of wave propagation by 81.4%.

Electron Microscopy of Shock Loaded Polycrystalline Beryllium

1974 ◽  
Vol 32 ◽  
pp. 506-507 ◽  
Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens
Keyword(s):  
Electron Microscopy ◽  
Wave Propagation ◽  
Structural Change ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Shock Loading ◽  
Slip Systems ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

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