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1

Memory dependent triple-phase-lag thermo-elasticity in thermo-diffusive medium

Yadav Anand Kumar, Singh Aarti, Jurczak Paweł

International Journal of Applied Mechanics and Engineering

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2023

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Vol. 28, no. 4

137--162

EN

The objective of the paper is to look at the propagation and reflection of plane waves in a thermo-diffusion isotropic medium. The reflection of plane waves in a thermo-diffusion medium was investigated in this study with reference to triple phase lag thermo-elasticity. The memory dependent derivative (MDD) is applied for this investigation. The fundamental equations are framed and solved for a particular plane. The four plane waves that are propagating across the medium are, shown namely: longitudinal displacement, P-wave, thermal diffusion T-wave, mass diffusion MD-wave and shear vertical SV-wave. These four plane wave velocities are listed for a specific medium, illustrating the impact of the diffusion coefficient and are graphically represented. Expressions for the reflection coefficient for the incidence plane wave are produced from research on the reflection of plane waves from the stress-free surface. It should be noted that these ratios are graphically represented and shown when diffusion and memory dependent derivative (MDD) factors are in play. The new model is relevant to many different fields, including semiconductors, earth- engineering, and electronics, among others, where thermo-diffusion elasticity is significant. Diffusion is a technique that can be applied to the production of integrated circuits, MOS transistors, doped polysilicon gates for the base and emitter in transistors, as well as for efficient oil extraction from oil reserves. Wave propagation in a thermos-diffusion elastic media provides crucial information about the presence of fresh and enhanced waves in a variety of technical and geophysical contexts. For experimental seismologists, developers of new materials, and researchers, this model might be useful in revising earthquake estimates.

2

Propagation and reflection of magneto-elastic plane waves at the free surface of a rotating micropolar fibre-reinforced medium with voids

Anya Augustine Igwebuike, Khan Aftab

Journal of Theoretical and Applied Mechanics

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2019

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Vol. 57 nr 4

869--881

EN

This work investigates rotational effects on propagation and reflection of waves at the free surface of a micropolar fibre-reinforced medium with voids under magnetic fields. When the P-wave is incident on the free surface, there exist four coupled reflected plane waves traveling in the medium; quasi-longitudinal displacement (qLD) wave, quasi-transverse displacement (qTD) wave, quasi-transverse microrotational (qTM) wave and a wave due to voids. Normal mode analysis is adopted in concomitant with Snell’s laws, and appropriate boundary conditions in determination of the solution. Amplitude ratios which correspond to reflected waves in vertical and horizontal components are presented analytically and graphically.

3

Reflection of PlaneWaves at Micropolar Piezothermoelastic Half-space

Kumar R., Sharma N., Lata P., Marin M.

Computational Methods in Science and Technology

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2018

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Vol. 24, No. 2

113--124

EN

A problem of reflection at a free surface of micropolar orthotropic piezothermoelastic medium is discussed in the present paper. It is found that there exist five type plane waves in micropolar orthotropic piezothermoelastic medium, namely quasi longitudinal displacement wave (quasi LD wave), quasi thermal wave (quasi T wave), quasi CD-I, quasi CD-II wave and electric potential wave (PE wave). The amplitude ratios corresponding to reflected waves are obtained numerically. The effect of angle of incidence and thermopiezoelectric interactions on the reflected waves are studied for a specific model. Some particular cases of interest are also discussed.

4

Diagnostics of Direct Current motor with application of acoustic signals, reflection coefficients and K-Nearest Neighbor classifier

Głowacz A., Głowacz W.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 5a

231-233

EN

One of the main problems faced by engineers, is to ensure the operation of Direct Current motors. In this paper a pattern recognition method was used to provide the diagnostics of dc motor. This method is based on a study of acoustic signal. Plan of study of acoustic signals for two conditions of Direct Current motor was proposed. Studies were carried out for algorithms of data processing: reflection coefficients and K-Nearest Neighbor classifier with Manhattan distance. Developed method can be performed automatically. This system is a significant step towards the maintenance-free diagnostic systems of Direct Current motors.

PL

Jednym z podstawowych problemów, z jakim spotykają się inżynierowie, jest zapewnienie funkcjonowania silników elektrycznych. W niniejszej pracy metoda rozpoznawania wzorców została użyta do diagnostyki silnika prądu stałego. Metoda ta oparta jest na badaniu sygnału akustycznego. Zaproponowano plan badania sygnałów akustycznych dla dwóch stanów silnika prądu stałego. Badania zostały przeprowadzone dla algorytmów przetwarzania danych: współczynników odbiciowych i klasyfikatora K-Najbliższego Sąsiada z metryką Manhattan. Opracowana metoda może być wykonywana automatycznie. System ten jest istotnym krokiem w kierunku bezobsługowych systemów diagnostycznych silników prądu stałego.

5

Influences of magnetic field on wave propagation in generalized thermoelastic solid with diffusion

Abo-Dahab S. M., Singh B.

Archives of Mechanics

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2009

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Vol. 61, nr 2

121-136

EN

This paper is devoted to estimation of the influence of magnetic field in an elastic solid half-space under thermoelastic diffusion. The governing equations in xz-plane are solved taking into consideration the GL model. The reflection of dilatational (P) wave and shear vertical (SV) wave splits into four waves, namely: P wave, thermal wave, mass diffusion wave and SV wave. The reflection phenomena of P and SV waves from the free surface of an elastic solid with thermoelastic diffusion, under the influence of magnetic field is considered. The expressions for the reflection coefficients for the four reflected waves are obtained. These reflection coefficients are found to depend upon the angle of incidence 0 of P and SV waves, thermoelastic diffusion, magnetic field and other material parameters. The numerical values for the reflection coefficients are calculated analytically and presented graphically for various values of these parameters. Relevant results of previous investigations are deduced as special cases from this study.

6

Plane wave propagation in a generalized thermoelastic solid in the presence of cracks

Singh B.

International Journal of Applied Mechanics and Engineering

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2008

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Vol. 13, no 1

239-250

EN

Reflection of pIane waves from a free surface of a generalized thermoelastic solid half-space in the presence of cracks is studied. Analytical expressions for reflection coefficients are derived for incident P and SV waves. These coefficients are computed numerically for different regimes of crack connections and shown graphically with the angle of incidence of striking wave.

7

Two-component decomposition of linear discrete one-dimensional large scale systems :(report)

Szaraniec E.

Czasopismo Techniczne. Elektrotechnika

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2006

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R. 103, z. 3-E

77-81

EN

One-dimensional system, containing very large number of facultatively arranged elements, is splitted up into two parallel components. Resulting one-dimensional very large scale submodels exhibit an advantageous ordering of elements. All the Schur parameters (reflection coefficients) are of the same sign in the first submodel whereas they alternate in sign in the another.

PL

Jednowymiarowy system zawierający wielką liczbę dowolnie ułożonych elementów może być rozdzielony na dwie równoległe składowe. Wynikowy jednowymiarowy submodel wielkiej skali ma korzystne uporządkowanie elementów. W pierwszym submodelu wszystkie parametry Schura (współczynniki odbić) mają ten same znak, a w drugim - znaki są naprzemienne.

8

Reflection/transmission of plane SH wave through a self-reinforced elastic layer between two half-spaces

Chaudhary S., Kaushik V., Tomar S.

Acta Geophysica Polonica

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2004

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Vol. 52, nr 2

219-235

EN

The reflection and transmission of plane SH wave through a self-rein-forced elastic layer sandwiched between two homogeneous viscoelastic solid half-spaces has been studied. The expressions for reflection and transmission coefficients are obtained. These coefficients are computed against the angle of incidence, normalized wave number and the reinforced parameters. The results obtained have been presented graphically. The problem studied by Borcherdt has been reduced as a special case of our problem. It is found that reflection and transmission coefficients depend on the angle of incidence, normalized wave number and the reinforcement parameters of the sandwiched layer.