Wave Propagation in Microstretch Thermoelastic Plate Bordered with Layers of Inviscid Liquid

2009 ◽  
Vol 5 (2) ◽  
pp. 171-184 ◽  
Author(s):  
Rajneesh Kumar ◽  
Geeta Partap
Keyword(s):  
Short Wavelength ◽  
Wave Mode ◽  
Free Vibrations ◽  
Inviscid Liquid ◽  
Conducting Plate ◽  
Symmetric Wave ◽  
Secular Equations ◽  
Thermoelastic Plate ◽  
Thermally Conducting ◽  
Crystal Composite

The propagation of free vibrations in microstretch thermoelastic homogeneous isotropic, thermally conducting plate bordered with layers of inviscid liquid on both sides subjected to stress free thermally insulated and isothermal conditions is investigated in the context of Lord and Shulman (L‐S) and Green and Lindsay (G‐L) theories of thermoelasticity. The secular equations for symmetric and skewsymmetric wave mode propagation are derived. The regions of secular equations are obtained and short wavelength waves of the secular equations are also discussed. At short wavelength limits, the secular equations reduce to Rayleigh surface wave frequency equations. Finally, the numerical solution is carried out for magnesium crystal composite material plate bordered with water. The dispersion curves for symmetric and skew‐symmetric wave modes are computed numerically and presented graphically.

SomeConsiderations on the Rayleigh–Lamb Wave Propagation in Visco-thermoelastic Plates

2005 ◽  
Vol 11 (10) ◽  
pp. 1311-1335 ◽  
Author(s):  
J. N. Sharma
Keyword(s):  
Complete Information ◽  
Wave Mode ◽  
Attenuation Coefficients ◽  
Conducting Plate ◽  
Thermoelastic Plates ◽  
Symmetric Wave ◽  
Secular Equations ◽  
Copper Material ◽  
Thermally Conducting ◽  
Lamb Wave Propagation

The aim of present paper is to study the thermoelastic interaction in an infinite Kelvin–Voigt-type viscoelastic, thermally conducting plate. The upper and lower surfaces of the plate are subjected to stress-free/rigidly fixed, thermally insulated or isothermal boundary conditions. Coupled dynamical thermoelasticity is employed to study the problem. We derive complex secular equations for the plate in closed from and isolated mathematical conditions for symmetric and skew-symmetric wave mode propagation in completely separate terms. The results for coupled and uncoupled theories of thermoelasticity have been obtained as particular cases from the derived secular equations. In general, the obtained secular equations are complex each of these on separating real and imaginary parts leads to two real frequency equations. These equations contain complete information regarding wavenumber, phase velocity, group velocity and attenuation coefficients of different propagating modes. The regions and the corresponding forms of Rayleigh–Lamb-type secular equations have been obtained and discussed in addition to Lame modes, decoupled shear horizontal modes and thin plate results. At short wavelength limits, the secular equations for symmetric and skew-symmetric waves in stress-free insulated and stress-free isothermal plate reduce to Rayleigh surface wave frequency equations. The amplitudes of temperature and displacement components during symmetric and skew-symmetric motion of the plate have been computed and discussed. In order to illustrate and compare the theoretical results, the numerical solution is carried out for copper material by using the functional iteration method. The dispersion curves, attenuation coefficients, amplitudes of temperature change, and displacements in case of symmetric and skew-symmetric wave modes are presented graphically.

Crested Waves in Thermoelastic Plates Immersed in Liquid

2005 ◽  
Vol 11 (3) ◽  
pp. 347-370 ◽  
Author(s):  
J. N. Sharma ◽  
Vijayata Pathania
Keyword(s):  
Temperature Change ◽  
Lamb Waves ◽  
Inviscid Liquid ◽  
Conducting Plate ◽  
Thermoelastic Plates ◽  
Special Cases ◽  
Secular Equations ◽  
Thermally Conducting ◽  
Thermoelastic Waves ◽  
Wave Modes

The propagation of circularly crested generalized thermoelastic waves in a homogeneous isotropic, thermally conducting plate, bordered with layers of inviscid liquid or half-space of inviscid liquid on both sides, is investigated in the context of conventional coupled thermoelasticity, and Lord-Shulman and Green-Lindsay theories of thermoelasticity. We derive secular equations for a circular homogeneous isotropic plate in closed form and isolated mathematical conditions for symmetric and antisymmetric wave modes in completely separate terms. Results for the uncoupled theory of thermoelasticity have been obtained as a particular case from the present one. Special cases, such as Lam6 modes, short wavelength waves, and thin plate waves of the secular equation, are also discussed. The secular equations for leaky Lamb waves are also obtained and deduced. The amplitudes of displacement components and temperature change have also been computed and studied. Finally, the numerical solution is carried out for aluminum epoxy composite material bordered with water. The dispersion curves for symmetric and antisymmetric wave modes and amplitudes of displacement and temperature change in the case of fundamental symmetric (SO) and skew symmetric (AO) modes are presented in order to illustrate and compare the theoretical results. The theory and numerical computations are found to be in close agreement.

Scattering of the Fundamental Symmetric Wave Mode Incident at a Defect on the Blind Side of a Weep Hole in an Isotropic Plate

2014 ◽  
Vol 891-892 ◽  
pp. 1237-1242 ◽  
Author(s):  
Benjamin Steven Vien ◽  
Nithurshan Nadarajah ◽  
Wing Kong Chiu ◽  
L.R. Francis Rose
Keyword(s):  
Isotropic Plate ◽  
Wave Mode ◽  
Blind Side ◽  
Edge Waves ◽  
Computational Simulations ◽  
Metallic Structures ◽  
Element Simulation ◽  
Symmetric Wave ◽  
Open Hole ◽  
Non Destructive

The scattering of a fundamental symmetric wave mode by a notch on the blind side of weep hole is described in this paper. It will report on findings obtained from computational simulations to determine the effect and interaction of the impinging waves with the defect on the open hole located on the blind side of the incident wave. The finite element simulation results showed mode conversions of fundamental modes, leaky edge waves on the circumferential surface and source-like diffractions radiating from the tip of the notch and hole. These findings highlight the potential of applying this wave phenomenon to quantify defect located hard-to-inspect areas by positioning actuator and sensor in accessible regions of metallic structures and is relevant to the development and improvement of current techniques in non-destructive inspection of metallic structures

scholarly journals Propagation of waves in the layer of a thermo-viscoelastic transversely isotropic medium

2016 ◽  
Vol 21 (1) ◽  
pp. 21-35
Author(s):  
R.R. Gupta ◽  
R.R. Gupta
Keyword(s):  
Wave Propagation ◽  
Temperature Distribution ◽  
Isotropic Medium ◽  
Lamb Waves ◽  
Transversely Isotropic ◽  
Type Ii ◽  
Transversely Isotropic Medium ◽  
Symmetric Wave ◽  
Secular Equations ◽  
Propagation Of Waves

Abstract The article is presented to enhance our knowledge about the propagation of Lamb waves in the layer of a viscoelastic transversely isotropic medium in the context of thermoelasticity with GN theory of type-II and III. Secular equations for symmetric and skew-symmetric modes of wave propagation in completely separate terms are derived. The amplitudes of displacements and temperature distribution were also obtained. Finally, the numerical solution was carried out for cobalt and the dispersion curves, amplitudes of displacements and temperature distribution for symmetric and skew-symmetric wave modes are presented to evince the effect of anisotropy. Some particular cases are also deduced.

scholarly journals Collisionless Damping of Fast and Ion?Cyclotron Surface Waves

1993 ◽  
Vol 46 (2) ◽  
pp. 271 ◽  
Author(s):  
GW Rowe
Keyword(s):  
Surface Waves ◽  
Short Wavelength ◽  
Mode Conversion ◽  
Low Frequency ◽  
Wave Mode ◽  
Alfven Wave ◽  
Field Boundary ◽  
First Order ◽  
Vacuum Interface ◽  
Ion Cyclotron

A recently developed general kinetic theory of surface waves is used to calculate the collisionless damping of low frequency fast and ion-cyclotron surface waves on a magnetised plasma-vacuum interface. In particular, the possibility of Cherenkov (Landau and transit-time magnetic) absorption by electrons is accounted for, assuming a bi-Maxwellian distribution of electrons in velocity space. It is shown that in general the surface waves are damped via mode conversion to a short-wavelength mode, such as the kinetic Alfven wave, which is subsequently Landau absorbed within the plasma. For high temperatures this short-wavelength mode can also be radiated into the plasma without being completely absorbed. It is also shown that the related ion-sound surface wave mode and instability identified by Alexandrov et al. (1984) are unphysical, and are the result of neglecting the gas pressure in the first-order magnetic field boundary condition.

Modeling Hypervelocity-Impact-Induced Shock Waves for Characterizing Orbital Debris-Produced Damage

2016 ◽  
Vol 83 (8) ◽  
Author(s):  
Menglong Liu ◽  
Zhongqing Su ◽  
Qingming Zhang ◽  
Renrong Long
Keyword(s):  
Outer Space ◽  
Three Dimensional ◽  
Wave Mode ◽  
Wide Frequency Range ◽  
Hypervelocity Impact ◽  
Orbital Debris ◽  
Symmetric Wave ◽  
Particle Hydrodynamics ◽  
First Arrival ◽  
Complex Features

Hypervelocity impact (HVI) is a scenario involving an impacting velocity in excess of 1 km/s. Ubiquitous in outer space, paradigms of HVI are typified by the collision between orbital debris and spacecraft. HVI features transient, localized, and extreme material deformation under which the induced acoustic emission (AE) signals present unique yet complex features. A dedicated modeling and numerical simulation approach, based on the three-dimensional smooth-particle hydrodynamics (SPH), was developed to gain an insight into characteristics of HVI-induced AE propagation. With the approach, both normal and oblique HVI scenarios were interrogated, and material failure in both cases was predicted. The coincidence in results between simulation and HVI experiment, as observed at a qualitative degree, has demonstrated the effectiveness of the modeling. Signal analysis shows that the shock wave converts to Lamb wave quickly as propagation from HVI spot, with the zeroth-order symmetric wave mode (S0) (i.e., the first-arrival wave) dominating wave signal energy. S0 is observed dispersive in a wide frequency range with majority of it below 1 MHz. In comparison, the antisymmetric wave mode distributes in a range below 200 kHz with a peak value at 30 kHz. S0 was employed to pinpoint the location of HVI, using an enhanced delay-and-sum-based diagnostic imaging algorithm, which was validated by locating orbital debris-induced orifice in space structures, showing precise identification results.

scholarly journals Study of Axi-Symmetric Vibrations in a Micropolar Transversely Isotropic Layer

2019 ◽  
Vol 24 (2) ◽  
pp. 259-268
Author(s):  
R.R. Gupta ◽  
R.R. Gupta
Keyword(s):  
Wave Propagation ◽  
Isotropic Medium ◽  
Lamb Waves ◽  
Transversely Isotropic ◽  
Isotropic Layer ◽  
Transversely Isotropic Medium ◽  
Symmetric Wave ◽  
Special Cases ◽  
Secular Equations ◽  
Transversely Isotropic Layer

Abstract The present investigation deals with the propagation of circular crested Lamb waves in a homogeneous micropolar transversely isotropic medium. Secular equations for symmetric and skew-symmetric modes of wave propagation in completely separate terms are derived. The amplitudes of displacements and microrotation are computed numerically for magnesium as a material and the dispersion curves, amplitudes of displacements and microrotation for symmetric and skew-symmetric wave modes are presented graphically to evince the effect of anisotropy. Some special cases of interest are also deduced.

GENERALIZED THERMOELASTIC WAVES IN MICROSTRETCH PLATES LOADED WITH FLUID OF VARYING TEMPERATURE

2011 ◽  
Vol 03 (03) ◽  
pp. 563-586 ◽  
Author(s):  
S. KUMAR ◽  
J. N. SHARMA ◽  
Y. D. SHARMA
Keyword(s):  
Wave Motion ◽  
Secular Equation ◽  
Long Wavelength ◽  
Inviscid Liquid ◽  
Thermoelastic Plates ◽  
Special Cases ◽  
Secular Equations ◽  
Velocity Attenuation ◽  
Generalized Thermoelastic ◽  
Thermoelastic Waves

In the present paper, the theory of generalized thermo-microstretch elasticity has been employed to study the propagation of straight and circular crested waves in microstretch thermoelastic plates bordered with inviscid liquid layers (or half-spaces), with varying temperature on both sides. The secular equations governing the wave motion in both rectangular and cylindrical plates have been investigated. The results in the case of thin (long wavelength) and thick (short wavelength) plates have also been obtained and discussed as special cases of this work. The secular equation in the case of microstretch coupled with thermoelastic, micropolar thermoelastic and thermoelastic plates can be obtained from the present analysis by an appropriate choice of relevant parameters. The results have been deduced and compared with the relevant publications available in the literature at the appropriate stages of this work. Finally, the analytical developments have been illustrated numerically for aluminum–epoxy-like material sandwiched in the inviscid liquid. The computer simulated results in respect of phase velocity, attenuation coefficient, specific loss factor of energy dissipation and relative frequency shift due to liquid layers on both sides of the plate are presented graphically.

Sign in / Sign up

Export Citation Format

Share Document