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1 – 10 of 222Manjeet Kumar, Xu Liu, Kapil Kumar Kalkal, Virender Dalal and Manjeet Kumari
The purpose of this paper is to study the propagation of inhomogeneous waves in a partially saturated poro-thermoelastic media through the examples of the free surface of such…
Abstract
Purpose
The purpose of this paper is to study the propagation of inhomogeneous waves in a partially saturated poro-thermoelastic media through the examples of the free surface of such media..
Design/methodology/approach
The mathematical model evolved by Zhou et al. (2019) is solved through the Helmholtz decomposition theorem. The propagation velocities of bulk waves in partially saturated poro-thermoelastic media are derived by using the potential functions. The phase velocities and attenuation coefficients are expressed in terms of inhomogeneity angle. Reflection characteristics (phase shift, loci of vertical slowness, amplitude, energy) of elastic waves are investigated at the stress-free thermally insulated boundary of a considered medium. The boundary can be permeable or impermeable. The incident wave is portrayed with both attenuation and propagation directions (i.e. inhomogeneous wave). Numerical computations are executed by using MATLAB.
Findings
In this medium, the permanence of five inhomogeneous waves is found. Incidence of the inhomogeneous wave at the thermally insulated stress-free surface results in five reflected inhomogeneous waves in a partially saturated poro-thermoelastic media. The reflection coefficients and splitting of incident energy are obtained as a function of propagation direction, inhomogeneity angle, wave frequency and numerous thermophysical features of the partially saturated poro-thermoelastic media. The energy of distinct waves (incident wave, reflected waves) accompanying interference energies between distinct pairs of waves have been exhibited in the form of an energy matrix.
Originality/value
The sensitivity of propagation characteristics (velocity, attenuation, phase shift, loci of vertical slowness, energy) to numerous aspects of the physical model is analyzed graphically through a particular numerical example. The balance of energy is substantiated by virtue of the interaction energies at the thermally insulated stress-free surface (opened/sealed pores) of unsaturated poro-thermoelastic media through the bulk waves energy shares and interaction energy.
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Vijay Chawla, Sanjeev Ahuja and Varsha Rani
The purpose of this paper is to study the fundamental solution in transversely isotropic micropolar thermoelastic media. With this objective, the two-dimensional general solution…
Abstract
Purpose
The purpose of this paper is to study the fundamental solution in transversely isotropic micropolar thermoelastic media. With this objective, the two-dimensional general solution in transversely isotropic thermoelastic media is derived.
Design/methodology/approach
On the basis of the general solution, the fundamental solution for a steady point heat source on the surface of a semi-infinite transversely isotropic micropolar thermoelastic material is constructed by six newly introduced harmonic functions.
Findings
The components of displacement, stress, temperature distribution and couple stress are expressed in terms of elementary functions. From the present investigation, a special case of interest is also deduced and compared with the previous results obtained.
Practical implications
Fundamental solutions can be used to construct many analytical solutions of practical problems when boundary conditions are imposed. They are essential in the boundary element method as well as the study of cracks, defects and inclusions.
Originality/value
Fundamental solutions for a steady point heat source acting on the surface of a micropolar thermoelastic material is obtained by seven newly introduced harmonic functions. From the present investigation, some special cases of interest are also deduced.
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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 possesses…
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.
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Manjeet Kumar, Jai Bhagwan, Pradeep Kaswan, Xu Liu and Manjeet Kumari
The purpose of this study is to investigate the reflection of plane waves in a double-porosity (DP) thermoelastic medium.
Abstract
Purpose
The purpose of this study is to investigate the reflection of plane waves in a double-porosity (DP) thermoelastic medium.
Design/methodology/approach
To derive the theoretical formulas for elastic wave propagation velocities through the potential decomposition of wave-governing equations. The boundary conditions have been designed to incorporate the unique characteristics of the surface pores, whether they are open or sealed. This approach provides a more accurate and realistic mathematical interpretation of the situation that would be encountered in the field. The reflection coefficients are obtained through a linear system of equations, which is solved using the Gauss elimination method.
Findings
The solutions obtained from the governing equations reveal the presence of five inhomogeneous plane waves, consisting of four coupled longitudinal waves and a single transverse wave. The energy ratios of reflected waves are determined for both open and sealed pores on the stress-free, the thermally insulated surface of DP thermoelastic medium. In addition, the energy ratios are compared for the cases of a DP medium and a DP thermoelastic medium.
Originality/value
A numerical example is considered to investigate the effect of fluid type in inclusions, temperature and inhomogeneity on phase velocities and attenuation coefficients as a function of frequency. Finally, a sensitivity analysis is performed graphically to observe the effect of the various parameters on propagation characteristics, such as propagation/attenuation directions, phase shifts and energy ratios as a function of incident direction in double-porosity thermoelasticity medium.
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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) are used…
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.
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Sohit Jatain, Sunita Deswal and Kapil Kumar Kalkal
The purpose of this paper is to establish a two-dimensional model of Green–Lindsay theory for micropolar magneto-thermoelastic medium to study the photothermal effect. The model…
Abstract
Purpose
The purpose of this paper is to establish a two-dimensional model of Green–Lindsay theory for micropolar magneto-thermoelastic medium to study the photothermal effect. The model is used to study the coupling between elastic waves and plasma waves generated due to thermal changes in a micropolar elastic medium.
Design/methodology/approach
Normal mode analysis is used to obtain the analytical solutions of the governing equations.
Findings
Effects of magnetic field, micropolarity, photothermal and time are highlighted on various physical fields such as stresses, temperature, displacement and carrier density. The above physical fields also conform to the boundary conditions. It is further observed that all the physical quantities become zero outside some bounded region of space, thus confirming the notion of generalized theory of thermoelasticity.
Originality/value
The values of physical fields are computed numerically using MATLAB software considering material constants for silicon. Furthermore, the effects are depicted graphically and analyzed accordingly. The study is valuable for the analysis of thermoelastic problems involving magnetic field, micropolarity and elastic deformations.
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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 temperature-dependent…
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.
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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 the…
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.
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Vipin Gupta, Rajesh Kumar, Rajneesh Kumar and M.S. Barak
This paper aims to study the energy ratios of plane waves on an interface of nonlocal thermoelastic halfspace (NTS) and nonlocal orthotropic piezothermoelastic half-space (NOPS).
Abstract
Purpose
This paper aims to study the energy ratios of plane waves on an interface of nonlocal thermoelastic halfspace (NTS) and nonlocal orthotropic piezothermoelastic half-space (NOPS).
Design/methodology/approach
The memory-dependent derivatives (MDDs) approach with a hyperbolic two-temperature (HTT), three-phase lag theory is used here to study how the energy ratios change at the interface with the angle of incidence.
Findings
Plane waves that travel through NTS and hit the interface as a longitudinal wave, a thermal wave, or a transversal wave send four waves into the NOPS medium and three waves back into the NTS medium. The amplitude ratios of the different waves that are reflected and transmitted are used to calculate the energy ratios of the waves. It is observed that these ratios are affected by the HTT, nonlocal and MDD parameters.
Research limitations/implications
The energy ratios correspond to four distinct models; nonlocal HTT with memory, nonlocal HTT without memory, local HTT with memory and nonlocal classical-two-temperature with memory concerning the angle of incidence from 0 degree to 90 degree.
Practical implications
This model applies to several fields, including earthquake engineering, soil dynamics, high-energy particle physics, nuclear fusion, aeronautics and other fields where nonlocality, MDD and conductive temperature play an important role.
Originality/value
The authors produced the submitted document entirely on their initiative, with equal contributions from all of them.
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Rajneesh Kumar, Raj Rani Gupta and Kuldeep Kumar
A dynamical two‐dimensional problem of a homogeneous transversely isotropic fibre‐reinforced generalized thermoelastic solid with an overlying acoustic fluid layer has been…
Abstract
A dynamical two‐dimensional problem of a homogeneous transversely isotropic fibre‐reinforced generalized thermoelastic solid with an overlying acoustic fluid layer has been considered to investigate disturbance due to mechanical load. Laplace and Fourier transform techniques are applied to solve the problem. Uniformly distributed and linearly distributed forces are applied to illustrate the utility of the approach. A numerical inversion technique has been applied to obtain the solution in the physical domain. Numerical results are obtained and presented graphically to show the effect of anisotropy along with the comparison of homogeneous transversely isotropic fibre‐reinforced generalized thermoelastic solid and isotropic elastic solid.
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