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Article
Publication date: 1 January 2009

Mohamed Othman and Ya Qin Song

The theory of generalized thermoelasticity, based on the Lord‐Shulman theory (LS) with one relaxation time and the Green‐Naghdi theory (GN) (of type II) without energy…

Abstract

The theory of generalized thermoelasticity, based on the Lord‐Shulman theory (LS) with one relaxation time and the Green‐Naghdi theory (GN) (of type II) without energy dissipation, as well as the classical dynamical coupled theory (CD), is used to study the electromagneto‐thermoelastic interactions in a semi‐infinite perfectly conducting solid subjected to a thermal shock on its surface. The entire elastic medium is rotating with a uniform angular velocity. There acts an initial magnetic field parallel to the plane boundary of the half‐space. The medium deformed because of thermal shock, the rotation and due to the application of the magnetic field. The normal mode analysis is used to obtain the exact expressions for the considered variables. The distributions of the variables considered are represented graphically for two different cases. From the distributions, the wave type heat propagation in the medium can be found. This indicates that the generalized heat conduction mechanism is completely different in essence from the classic Fourier’s law. Comparisons are made with the results predicted by the three theories in the presence and absence of rotation and a magnetic field.

Details

Multidiscipline Modeling in Materials and Structures, vol. 5 no. 1
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 11 January 2018

Mohamed I.A. Othman, S.M. Abo-Dahab and Haneen A. Alosaimi

The purpose of this paper is to study a model of the equations of a two-dimensional problem in a half space, whose surface in a free micropolar thermoelastic medium…

Abstract

Purpose

The purpose of this paper is to study a model of the equations of a two-dimensional problem in a half space, whose surface in a free micropolar thermoelastic medium possesses cubic symmetry as a result of inclined load. The problem is formulated in the context of Green-Naghdi theory of type II (G-N II) (without energy dissipation) and of type III (G-N III) (with energy dissipation) under the effect of magnetic field.

Design/methodology/approach

The normal mode analysis is used to obtain the exact expressions of the physical quantities.

Findings

The numerical results are given and presented graphically when the inclined load and magnetic field are applied. Comparisons are made with the results predicted by G-N theory of both types II and III in the presence and absence of the magnetic field and for different values of the angle of inclination.

Originality/value

In the present work, the authors study the influence of inclined load and magnetic field in a micropolar thermoelastic medium in the context of the G-N theory of both types II and III. Numerical results for the field quantities are obtained and represented graphically.

Details

Multidiscipline Modeling in Materials and Structures, vol. 14 no. 2
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 1 March 2005

Mohamed I. A. Othman

A two‐dimensional coupled problem in electromagneto‐thermoelasticity for a thermally and electrically conducting half‐space solid whose surface is subjected to a thermal…

Abstract

A two‐dimensional coupled problem in electromagneto‐thermoelasticity for a thermally and electrically conducting half‐space solid whose surface is subjected to a thermal shock is considered. The problem is in the context of the Lord and Shulman’s generalized thermoelasticity with one relaxation time. There acts an initial magnetic field parallel to the plane boundary of the half‐space. The medium deformed because of thermal shock and due to the application of the magnetic field, there result an induced magnetic and an induced electric field in the medium. The Maxwell’s equations are formulated and the electromagneto‐thermoelastic coupled governing equations are established. The normal mode analysis is used to obtain the exact expressions for the considered variables. The distributions of the considered variables are represented graphically. From the distributions, it can be found the wave type heat propagation in the medium. This indicates that the generalized heat conduction mechanism is completely different from the classic Fourier’s in essence. In generalized thermoelasticity theory heat propagates as a wave with finite velocity instead of infinite velocity in medium. Comparisons are made with the results predicted by the coupled theory for two values of time.

Details

Multidiscipline Modeling in Materials and Structures, vol. 1 no. 3
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 19 June 2019

Mohamed I.A. Othman and Elsayed M. Abd-Elaziz

The purpose of this study is to obtain a general solution to the field equations of thermoelastic solid with voids and micro-temperatures under the gravitational field in…

Abstract

Purpose

The purpose of this study is to obtain a general solution to the field equations of thermoelastic solid with voids and micro-temperatures under the gravitational field in the context of the three theories, namely, coupled theory (CT), Lord and Shulman theory and Green and Lindsay theory.

Design/methodology/approach

The normal mode analysis is used to obtain the exact expressions for the considered variables. Comparisons are made with the results obtained in the three theories with and without gravity. Some particular cases are also deduced from the present investigation.

Findings

The effect of the gravity on the displacement, the micro-temperature vector, the temperature distribution, the normal stress, the changes in the volume fraction field and the heat flux moments have been depicted graphically.

Research limitations/implications

Some particular cases are also deduced from the present investigation.

Originality/value

The results of the physical quantities have been illustrated graphically by a comparison between three different theories in the presence and absence of gravity.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 9
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 18 July 2019

Mohamed I.A. Othman and Ahmed E. Abouelregal

The purpose of this paper is to investigate the dynamic response for a thermoelastic infinite medium with a spherical cavity in the context of the theory of…

Abstract

Purpose

The purpose of this paper is to investigate the dynamic response for a thermoelastic infinite medium with a spherical cavity in the context of the theory of two-temperature thermoelasticity without energy dissipation.

Design/methodology/approach

The cavity is fixed and subjected to a subjected to harmonically varying temperature.

Findings

The exact expressions for displacement, temperature and thermal stresses are computed and represented graphically. These distributions are calculated for a copper material and results are analyzed.

Originality/value

Effects of non-simple heat conduction, frequency of thermal vibrations and magnetic field are depicted graphically on the field variables.

Details

Multidiscipline Modeling in Materials and Structures, vol. 15 no. 5
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 27 November 2018

Mohamed I.A. Othman, Ramadan S. Tantawi and Mohamed I.M. Hilal

The purpose of this paper is to report effect of rotation of micropolar thermoelastic solid with microtemperatures heated by laser pulses. The problem was solved…

Abstract

Purpose

The purpose of this paper is to report effect of rotation of micropolar thermoelastic solid with microtemperatures heated by laser pulses. The problem was solved analytically to obtain the expressions of the physical quantities.

Design/methodology/approach

The analytical method used was the normal mode.

Findings

Numerical results for the physical quantities were presented graphically and the results were analyzed. The comparisons were established in variant cases of the effects used and then shown graphically.

Originality/value

In the present work, the authors shall discuss the effect of rotation and temperature-dependent properties with the laser pulses in the micropolar thermoelastic medium with microtemperatures. This problem is very important in more empirical branches such as the human body and earthquake engineering.

Details

Multidiscipline Modeling in Materials and Structures, vol. 15 no. 2
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 9 February 2018

Mohamed I.A. Othman and Montaser Fekry

The purpose of this paper is to study the effect of rotation and gravity on a homogeneous, isotropic, and generalized thermo-viscoelastic material with voids. The problem…

Abstract

Purpose

The purpose of this paper is to study the effect of rotation and gravity on a homogeneous, isotropic, and generalized thermo-viscoelastic material with voids. The problem is studied in the context of the coupled theory, Lord-Shulman theory with one relaxation time, and Green-Lindsay theory with two relaxation times.

Design/methodology/approach

The analytical method used was the normal mode analysis technique.

Findings

Numerical results for the physical quantities were analyzed and presented graphically. The graphical results indicated that the effects of rotation and gravity were observable physical effects on the thermo-viscoelastic material with voids. Comparisons were made between the results obtained in the absence and presence of rotation and gravity.

Originality/value

In the present work, the authors investigated the effect of rotation and gravity on thermo-viscoelastic medium with voids. Comparisons were also made between the three theories in the absence and the presence of rotation and gravity. Such problems are very important in many dynamical systems.

Details

Multidiscipline Modeling in Materials and Structures, vol. 14 no. 2
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 15 August 2019

Mohamed I.A. Othman, Samia Said and Marin Marin

In the present paper, the three-phase-lag (3PHL) model, Green-Naghdi theory without energy dissipation (G-N II) and Green-Naghdi theory with energy dissipation (G-N III…

Abstract

Purpose

In the present paper, the three-phase-lag (3PHL) model, Green-Naghdi theory without energy dissipation (G-N II) and Green-Naghdi theory with energy dissipation (G-N III) are used to study the influence of the gravity field on a two-temperature fiber-reinforced thermoelastic medium.

Design/methodology/approach

The analytical expressions for the displacement components, the force stresses, the thermodynamic temperature and the conductive temperature are obtained in the physical domain by using normal mode analysis.

Findings

The variations of the considered variables with the horizontal distance are illustrated graphically. Some comparisons of the thermo-physical quantities are shown in the figures to study the effect of the gravity, the two-temperature parameter and the reinforcement. Also, the effect of time on the physical fields is observed.

Originality/value

To the best of the author’s knowledge, this model is a novel model of plane waves of two-temperature fiber-reinforced thermoelastic medium, and gravity plays an important role in the wave propagation of the field quantities. It explains that there are significant differences in the field quantities under the G-N II theory, the G-N III theory and the 3PHL model because of the phase-lag of temperature gradient and the phase-lag of heat flux.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 12
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 12 June 2017

Mohamed I.A. Othman, Yassmin D. Elmaklizi and Nehal T. Mansoure

The purpose of this paper is to investigate the propagation of plane waves in an isotropic elastic medium under the effect of rotation, magnetic field and…

Abstract

Purpose

The purpose of this paper is to investigate the propagation of plane waves in an isotropic elastic medium under the effect of rotation, magnetic field and temperature-dependent properties with two‐temperatures.

Design/methodology/approach

The problem has been solved analytically by using the normal mode analysis.

Findings

The numerical results are given and presented graphically when mechanical and thermal force are applied. Comparisons are made with the results predicted by the three-phase-lag (3PHL) model and dual-phase-lag model in the presence and absence of cases where the modulus of elasticity is independent of temperature.

Originality/value

In this work, the authors study the influence of rotation and magnetic field with two‐temperature on thermoelastic isotropic medium when the modulus of elasticity is taken as a linear function of reference temperature in the context of the 3PHL model. The numerical results for the field quantities are obtained and represented graphically.

Details

Multidiscipline Modeling in Materials and Structures, vol. 13 no. 1
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 2 January 2018

Mohamed I.M. Hilal and Mohamed I.A. Othman

The purpose of this paper is to discuss the problem of thermoelasticity with voids under the gravity field in the context of a general form of heat conduction equation…

Abstract

Purpose

The purpose of this paper is to discuss the problem of thermoelasticity with voids under the gravity field in the context of a general form of heat conduction equation with some particular cases. The normal mode method used is to obtain the physical quantities.

Design/methodology/approach

The analytical method used was the normal mode.

Findings

Numerical results for the physical quantities are presented graphically and the results are analyzed thereafter. The comparisons are established between the theories for the physical quantities during the constant time and gravity and were shown graphically.

Originality/value

In the present work, the authors shall establish the general form for the heat conduction equation which contains the seven theories as well as the special cases in thermoelasticity with voids. The problem is very important in many dynamical systems.

Details

Multidiscipline Modeling in Materials and Structures, vol. 14 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

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