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Article
Publication date: 21 December 2017

Sunita Deswal, Baljit Singh Punia and Kapil Kumar Kalkal

The dual-phase-lag (DPL) model is applied to study the effect of the gravity field and micropolarity on the wave propagation in a two-temperature generalized thermoelastic…

Abstract

Purpose

The dual-phase-lag (DPL) model is applied to study the effect of the gravity field and micropolarity on the wave propagation in a two-temperature generalized thermoelastic problem for a medium. The paper aims to discuss this issue.

Design/methodology/approach

The exact expressions of the considered variables are obtained by using normal mode analysis.

Findings

Numerical results for the field quantities are given in the physical domain and illustrated graphically to show the effect of angle of inclination. Comparisons of the physical quantities are also shown in figure to study the effect of gravity and two-temperature parameter.

Originality/value

This paper is concerned with the analysis of transient wave phenomena in a micropolar thermoelastic half-space subjected to inclined load. The governing equations are formulated in the context of two-temperature generalized thermoelasticity theory with DPLs. A medium is assumed to be initially quiescent and under the effect of gravity. An analytical solution of the problem is obtained by employing normal mode analysis. Numerical estimates of displacement, stresses and temperatures are computed for magnesium crystal-like material and are illustrated graphically. Comparisons of the physical quantities are shown in figures to study the effects of gravity, two-temperature parameter and angle of inclination. Some particular cases of interest have also been inferred from the present problem.

Details

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

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Article
Publication date: 27 August 2020

Devender Sheoran, Ramesh Kumar, Sunil Kumar and Kapil Kumar Kalkal

The purpose of this paper is to study the reflection of plane waves in an initially stressed rotating thermoelastic diffusive medium with micro-concentrations and two-temperature.

Abstract

Purpose

The purpose of this paper is to study the reflection of plane waves in an initially stressed rotating thermoelastic diffusive medium with micro-concentrations and two-temperature.

Design/methodology/approach

A two-dimensional model of generalized thermoelasticity is considered. The governing equations are transformed into the non-dimensional forms using the dimensionless variables. Then, potential functions are introduced for the decoupling of the waves. Further, appropriate boundary conditions are assumed to completely solve the problem. Finally, numerical computations are performed using MATLAB.

Findings

The problem is solved analytically and it is found that there exist five coupled waves in addition to an independent micro-concentration wave in the considered medium. The amplitude ratios and energy ratios of these reflected waves have also been computed numerically for a specific material.

Originality/value

The modulus values of amplitude ratios are presented graphically to exhibit the effects of angular velocity, initial stress, two-temperature, diffusion and micro-concentration parameters. The expressions of energy ratios obtained in explicit form are also depicted graphically as functions of angle of incidence. The law of conservation of energy at the free surface during reflection phenomenon is also verified.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 4
Type: Research Article
ISSN: 0961-5539

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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: 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 two-temperature

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: 8 August 2016

Samia M Said

The dual-phase-lag (DPL) model and Lord-Shulman theory with one relaxation time are applied to study the effect of the gravity field, the magnetic field, and the…

Abstract

Purpose

The dual-phase-lag (DPL) model and Lord-Shulman theory with one relaxation time are applied to study the effect of the gravity field, the magnetic field, and the hydrostatic initial stress on the wave propagation in a two-temperature generalized thermoelastic problem for a medium with an internal heat source that is moving with a constant speed. The paper aims to discuss this issue.

Design/methodology/approach

The exact expressions of the considered variables are obtained by using normal mode analysis.

Findings

Numerical results for the field quantities are given in the physical domain and illustrated graphically in the absence and presence of the gravity field as well as the magnetic field. Comparisons are made between the results of the two different models with and without temperature dependent properties and for two different values of the hydrostatic initial stress. A comparison is also made between the results of the two different models for two different values of the time.

Originality/value

In the present work, the author shall formulate a two-temperature generalized magneto-thermoelastic problem for a medium with temperature dependent properties and with an internal heat source that is moving with a constant speed under the influence of a gravity field and a hydrostatic initial stress. Normal mode analysis is used to obtain the exact expressions for the displacement components, thermodynamic temperature, conductive temperature, and stress components. A comparison is carried out between the considered variables as calculated from the generalized thermoelasticity based on the DPL model and the L-S theory in the absence and presence of a magnetic field as well as a gravity field. Comparisons are also made between the results of the two theories with and without temperature dependent properties and for two different values of hydrostatic initial stress. A comparison is also made between the results of the two different models for two different values of the time.

Details

Multidiscipline Modeling in Materials and Structures, vol. 12 no. 2
Type: Research Article
ISSN: 1573-6105

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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: 9 November 2015

Mohamed I. Othman, W. M. Hasona and Nehal T. Mansour

The purpose of this paper is to introduce the Lord-Shulman (L-S), Green-Naghdi of type III (G-N III) and three phase lag (3PHL) theories to study the effect of a magnetic…

Abstract

Purpose

The purpose of this paper is to introduce the Lord-Shulman (L-S), Green-Naghdi of type III (G-N III) and three phase lag (3PHL) theories to study the effect of a magnetic field on generalized thermoelastic medium with two temperature.

Design/methodology/approach

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

Findings

The problem is used to obtain the analytical expressions of the displacement components, force stress, thermodynamic temperature and conductive temperature. The numerical results are given and presented graphically thermal force is applied. Comparisons are made with the results predicted by 3PHL, G-N III and L-S in the presence and absence of magnetic field as well as two temperature.

Originality/value

Generalized thermoelastic medium.

Details

Multidiscipline Modeling in Materials and Structures, vol. 11 no. 4
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 6 August 2010

Praveen Ailawalia, Sunit Kumar and Devinder Pathania

The purpose of this paper is to study the deformation of a rotating generalized thermoelastic medium with two temperatures under hydrostatic initial stress subjected to…

Abstract

Purpose

The purpose of this paper is to study the deformation of a rotating generalized thermoelastic medium with two temperatures under hydrostatic initial stress subjected to different types of sources.

Design/methodology/approach

The methodology applied here is the use of integral transforms to obtain the components of displacement, force stress, conductive temperature and temperature distribution in Laplace and Fourier domain. The general solution obtained is applied to a specific problem of a half‐space subjected to concentrated force, uniformly distributed force and a moving source. These components are then obtained in the physical domain by applying a numerical inversion method. Some particular cases are also discussed in the context of the problem. The results obtained are also presented graphically to show the effect of rotation and gravity.

Findings

The variations of all the quantities and for all the mediums are similar for concentrated force and distributed forces applied along the free surface of the solid. The values of these quantities are very close to each other for GTES and GTESWG. Deformation of a body depends on the nature of force applied as well as the type of boundary conditions. The variations of all the quantities are more uniform in nature when a force of constant magnitude moves along the surface of solid with some velocity.

Originality/value

Such types of problems in rotating media will find great applications in many dynamical systems and industries.

Details

Multidiscipline Modeling in Materials and Structures, vol. 6 no. 2
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 31 July 2019

Bin Chen, Yibo Zhao and Dong Li

This paper aims to understand the laser–tissue interaction mechanism during ophthalmic laser surgeries through numerical analysis. The influence of laser parameters and…

Abstract

Purpose

This paper aims to understand the laser–tissue interaction mechanism during ophthalmic laser surgeries through numerical analysis. The influence of laser parameters and the multipulse technique were investigated.

Design/methodology/approach

The ocular fundus was simplified as a multilayered homogenous medium model. Afterward, the multilayer Monte Carlo method was used to simulate the propagation and energy deposition of laser light, and a local thermal non-equilibrium two-temperature model was established to simulate the temperature variation of chromophores and surrounding tissue with different laser wavelength.

Findings

Through the model, the selective heating of chromophore (melanin and blood vessels) was clearly illustrated: 1) neglecting the laser energy absorbance by blood in the traditional model will cause significant errors in temperature calculation; 2) the non-thermal equilibrium heat transfer model was needed to obtain an accurate description of the thermal process when the dimensionless pulse width (tp*) is <105. For 532 nm Argon laser, the optimize tp* is around 105 and the appropriate energy density is 5 J/cm2; 3) multipulse technique makes the energy more concentrated within the melanin, thereby reducing the thermal damage in surrounding tissue, with most appropriate pulse number and duty cycle is 10 and 1/10.

Originality/value

Taking the blood absorption into account, the different temperature variations of melanin/vessels and surrounding tissue caused by the selective photo-thermolysis were simulated successfully. By understanding the mechanism of laser therapy, laser parameters and multipulse technique are suggested to improve the clinical results.

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: 1 November 1997

Tzu‐Fang Chen, Sui Lin and Joseph C.Y. Wang

Investigates errors of the reconstruction temperatures at boundaries caused by variation of the locations of two temperature sensors in a one‐dimensional inverse heat…

Abstract

Investigates errors of the reconstruction temperatures at boundaries caused by variation of the locations of two temperature sensors in a one‐dimensional inverse heat conduction problem (IHCP) by using a time marching implicit finite difference inverse solver. Numerical simulation results of selected functions indicate that errors of the reconstruction temperature at each boundary can be presented by a simple relation. Each relation contains an unknown coefficient which can be determined by using one numerical simulation through the inverse solver of a pair specified sensor locations. This relation can then be used for estimating the other recovery errors at the boundary without using the inverse solver.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 7 no. 7
Type: Research Article
ISSN: 0961-5539

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