M. I. A. Othman

Bio: M. I. A. Othman is an academic researcher from Zagazig University. The author has contributed to research in topics: Fourier transform & Elastic modulus. The author has an hindex of 3, co-authored 3 publications receiving 53 citations.

State space approach to the generalized thermoelastic problem with temperature-dependent elastic moduli and internal heat sources

Abstract: A two-dimensional equation of generalized thermoelasticity with one relaxation time in an isotropic elastic medium with the elastic modulus dependent on temperature and with an internal heat source is established using a Laplace transform in time and a Fourier transform in the space variable. The problem for the transforms is solved in the space of states. The problem of heating of the upper and the lower surface of a plate of great thickness by an exponential time law is considered. Expressions for displacements, temperature, and stresses are obtained in the transform domain. The inverse transform is obtained using a numerical method. Results of solving the problem are presented in graphical form. Comparisons are made with the results predicted by the coupled theory and with the case of temperature independence of the elastic modulus.

State space approach to the generalized thermoelastic problem with temperature-dependent elastic moduli and internal heat sources

Abstract: A two-dimensional equation of generalized thermoelasticity with one relaxation time in an isotropic elastic medium with the elastic modulus dependent on temperature and with an internal heat source is established using a Laplace transform in time and a Fourier transform in the space variable. The problem for the transforms is solved in the space of states. The problem of heating of the upper and the lower surface of a plate of great thickness by an exponential time law is considered. Expressions for displacements, temperature, and stresses are obtained in the transform domain. The inverse transform is obtained using a numerical method. Results of solving the problem are presented in graphical form. Comparisons are made with the results predicted by the coupled theory and with the case of temperature independence of the elastic modulus.

Effect of the thermal relaxation and magnetic field on generalized micropolar thermoelasticity

Abstract: The model of generalized micropolar magneto-thermoelasticity for a thermally and perfectly conducting half-space is studied. The initial magnetic field is parallel to the boundary of the half-space. The formulation is applied to the generalized thermo-elasticity theories of Lord and Shulman, Green and Lindsay, as well as to the coupled dynamic theory. The normal mode analysis is used to obtain expressions for the temperature increment, the displacement, and the stress components of the model at the interface. By using potential functions, the governing equations are reduced to two fourth-order differential equations. By numerical calculation, the variation of the considered variables is given and illustrated graphically for a magnesium crystal micropolar elastic material. Comparisons are performed with the results predicted by the three theories in the presence of a magnetic field.

The elastic wave motions for a photothermal medium of a dual-phase-lag model with an internal heat source and gravitational field

Abstract: In this work, the dual-phase-lag (DPL) heat transfer model is introduced to study the problem of an isotropic generalized thermoelastic medium with an internal heat source that is moving with a con...

Memory-dependent derivative effect on wave propagation of micropolar thermoelastic medium under pulsed laser heating with three theories

Abstract: The purpose of this paper is to introduce the phase-lag models (Lord-Shulman, dual-phase-lag and three-phase-lag) to study the effect of memory-dependent derivative and the influence of thermal loading due to laser pulse on the wave propagation of generalized micropolar thermoelasticity. The bounding plane surface is heated by a non-Gaussian laser beam with a pulse duration of 10 nanoseconds.,The normal mode analysis technique is used to obtain the exact expressions for the displacement components, the force stresses, the temperature, the couple stresses and the micro-rotation. Comparisons are made with the results predicted by three theories of the authors’ interest. Excellent predictive capability is demonstrated at a different time also.,The effect of memory-dependent derivative and the heat laser pulse on the displacement, the temperature distribution, the components of stress, the couple stress and the microrotation vector have been depicted graphically.,Some particular cases are also deduced from the present investigation.,The numerical results are presented graphically and are compared with different three theories for both in the presence and absence of memory-dependent effect and with the results predicted under three theories for two different values of the time.

Plane waves in a magneto-thermoelastic solids with voids and microtemperatures due to hall current and rotation

Abstract: In this study, the effect of hall current and rotation on a magneto-thermoelastic solid with microtemperatures and voids are investigated. The medium is permeated by a strong transverse magnetic field imposed perpendicularly on the displacement plane, the induced electric field being neglected. The normal mode analysis is used to obtain the exact expressions for the considered variables. Numerical simulated results are depicted graphically to show the effect of hall current, voids parameter and rotation on resulting quantities. The results indicate that the effect of hall current, voids parameter and rotation are very pronounced. Some particular cases of special interest have been deduced from the present investigation.

Ramp Type Heating in a Semiconductor Medium under Photothermal Theory

Abstract: The present investigation is concerned with study the two-dimensional deformation in a semi-infinite semiconducting medium subjected to ramp type heating. The deformation in the medium is caused subjected to a thermal source of ramp-type nature applied along the free surface of a semiconducting medium. The semiconductor thermoelastic medium is under the influence of an internal heat source of constant magnitude. Integral Transform method has been used to obtain the transformed expression of displacement components, stress components, temperature distribution, and carrier density. The transformed expressions are then inverted using numerical inversion technique. The effect of ramp-type source and thermoelectric coupling parameter on the components of displacement, force stress, temperature distribution, and carrier density has been shown graphically.

Effect of the gravity on the photothermal waves in a semiconducting medium with an internal heat source and one relaxation time

Abstract: The purpose of the present paper is to study the gravitational effect in a homogeneous isotropic semiconducting medium subjected to an internal heat source, based on Lord–Shulman theory. The problem is formulated in the dimensionless form and then solved analytically using the normal mode analysis method. The physical quantities are obtained and tested by a numerical study using the parameters of silicon as a target and presented graphically. The distribution of these quantities is represented graphically in the presence and absence of the internal heat source as well as gravity.