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1 – 10 of 197Rajneesh Kumar and Geeta Partap
The propagation of free vibrations in microstretch thermoelastic homogeneous isotropic, thermally conducting plate bordered with layers of inviscid liquid on both sides subjected…
Abstract
The propagation of free vibrations in microstretch thermoelastic homogeneous isotropic, thermally conducting plate bordered with layers of inviscid liquid on both sides subjected to stress free thermally insulated and isothermal conditions is investigated in the context of Lord and Shulman (L‐S) and Green and Lindsay (G‐L) theories of thermoelasticity. The secular equations for symmetric and skewsymmetric wave mode propagation are derived. The regions of secular equations are obtained and short wavelength waves of the secular equations are also discussed. At short wavelength limits, the secular equations reduce to Rayleigh surface wave frequency equations. Finally, the numerical solution is carried out for magnesium crystal composite material plate bordered with water. The dispersion curves for symmetric and skew‐symmetric wave modes are computed numerically and presented graphically.
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– The natural frequency of a diaphragm with residual stress in contact with a liquid is investigated theoretically in this paper. The paper aims to discuss these issues.
Abstract
Purpose
The natural frequency of a diaphragm with residual stress in contact with a liquid is investigated theoretically in this paper. The paper aims to discuss these issues.
Design/methodology/approach
An analytical calculation using the nondimensional added virtual mass incremental (NAVMI) factors is performed to find the dependency of the natural frequency on the residual stress when the diaphragm vibrating in contact with a liquid.
Findings
The analysis gives the residual stress contribution to the added virtual mass.
Originality/value
The magnitude of the added virtual mass depends on the residual stress. However, the magnitude of the natural frequency is found to be insignificant to the residual stress.
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Mohamed I.A. Othman, Sarhan Y. Atwa, Ebtesam E.M. Eraki and Mohamed F. Ismail
In this work, the thermoelastic response in a micro-stretch thermoelastic half-space submerged in an unlimited non-viscous fluid under gravity, the medium is studied using the…
Abstract
Purpose
In this work, the thermoelastic response in a micro-stretch thermoelastic half-space submerged in an unlimited non-viscous fluid under gravity, the medium is studied using the three-phase-lag model (3PHL) and Green-Naghdi theory (G-N III).
Design/methodology/approach
The normal mode analysis was the analytic technique used to obtain the exact formula of the physical quantities.
Findings
The magnesium crystal element is used as an application to compare the predictions induced by gravity on microstretch thermoelastic immersed in an infinite fluid of the three-phase-lag model with those for Green–Naghdi. Gravity has been noticed to have a major effect on all physical quantities. Comparisons were also made for three values of wave number and three values of the real part frequency.
Originality/value
This work is concerned with the thermoelastic micro-stretch solid immersed in an infinite and inviscid fluid and subjected to a gravitational field. The governing equations are formulated in the context of the 3PHL model and G-N theory. An analytical solution to the problem is obtained by employing normal mode analysis. Comparisons of the physical quantities are shown in figures to study the effects of gravity, wave number and the real part of the frequency.
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Jiaru Shao, Shangming Li, Zirui Li and Moubin Liu
The purpose of this paper is to investigate different baffles on mitigating liquid sloshing in a rectangular tank due to a horizontal excitation and to find out the optimal…
Abstract
Purpose
The purpose of this paper is to investigate different baffles on mitigating liquid sloshing in a rectangular tank due to a horizontal excitation and to find out the optimal selection of sloshing mitigation for practical applications.
Design/methodology/approach
The numerical study is conducted by using a proven improved smoothed particle hydrodynamics (SPH), which is convenient in tracking free surfaces and capable of obtaining smooth and correct pressure field.
Findings
Liquid sloshing effects in a rectangular tank with vertical middle baffles, horizontal baffles, T-shape baffles and porous baffles are investigated together with those without any baffles. It is found that the existence of baffles can mitigate sloshing effects and the mitigation performance depends on the shape, structure and location of the baffles. Considering the balance of sloshing mitigation performance and the complexity in structure and design, the I shaped and T shaped baffles can be good choices to mitigate sloshing effects.
Practical implications
The presented methodology and findings can be helpful in practical engineering applications, especially in ocean engineering and problems with large sloshing effects.
Originality/value
The SPH method is a meshfree, Lagrangian particle method, and therefore it is an attractive approach for modeling liquid sloshing with material interfaces, free surfaces and moving boundaries. In most previous literature, only simple baffles are investigated. In this paper, more complicated baffles are investigated, which can be helpful in practical applications and engineering designs.
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Miralam Mahdi, Mehrzad Shams and Reza Ebrahimi
The purpose of this paper is to study numerically the effects of heat transfer on the strength of shock waves emitted upon spherical bubble collapse.
Abstract
Purpose
The purpose of this paper is to study numerically the effects of heat transfer on the strength of shock waves emitted upon spherical bubble collapse.
Design/methodology/approach
The motion of bubble under ultrasound is predicted by solutions of the Navier‐Stokes equations for the gas inside a spherical bubble. The Gilmore model and the method of characteristics are used to model the shock wave emitted at the end of the bubble collapse.
Findings
The theory permits one to predict correctly the bubble radius‐time curve and the characteristics of shock wave in sulphuric acid solution. These simulations indicated that the heat transfer inside the bubble and the liquid layer plays a major role in the bubble behaviour and the strength of the shock waves. Also, the developed numerical scheme is checked for different gas bubble like air, Argon and Xenon. It is observed that the gas thermal conductivity plays an important role in the shock wave strength. A good agreement is observed by comparison of the results with the experimental data.
Originality/value
The effect of heat transfer on the emitted shock wave strength has not been studied previously. In this paper, a numerical scheme is developed to consider heat transfer on the shock. Also, this simulation is checked for different gas conductivities.
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Mohamed I.A. Othman and Mohamed F. Ismail
This paper aims to study the gravity effects on a micro-elongated thermoelastic layer under a fluid load, utilizing the Lord–Shulman (L-S) theory and the dual-phase-lag (DPL…
Abstract
Purpose
This paper aims to study the gravity effects on a micro-elongated thermoelastic layer under a fluid load, utilizing the Lord–Shulman (L-S) theory and the dual-phase-lag (DPL) model.
Design/methodology/approach
The analytical method used was the normal mode which partial differential equations transform into ordinary differential equations.
Findings
Aluminum epoxy numerical computations are carried out, and the results are graphed. The DPL model and the L-S theory are compared in the complete absence and presence of gravity. Comparisons were also made for three values of and it is observed that the gravity has quite a massive influence on all physical quantities.
Originality/value
In the present paper, the authors shall create the general equation for the energy equation, which includes the two theories (DPL and L-S) as well as the solution of micro-elongated thermoelasticity under fluid load. The problem is pretty important in many dynamical systems.
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Gerard Cummins and Marc P.Y. Desmulliez
The purpose of this paper is to present an exhaustive review of research studies and activities in the inkjet printing of conductive materials.
Abstract
Purpose
The purpose of this paper is to present an exhaustive review of research studies and activities in the inkjet printing of conductive materials.
Design/methodology/approach
This paper gives a detailed literature survey of research carried out in inkjet printing of conductive materials.
Findings
This article explains the inkjet printing process and the various types of conductive inks. It then examines the various factors that affect the quality of inkjet printed interconnects such as printing parameters, materials and substrate treatments. Methods of characterising both the inkjet printing process and the electrical properties of printed conductive materials are also presented. Finally relevant applications of this technology are described.
Originality/value
Inkjet printing is currently one of the cheapest direct write techniques for manufacturing. The use of this technique in electronic manufacturing, where interconnects and other conductive features are required is an area of increasing relevance to the fields of electronics manufacturing, packaging and assembly. This review paper would therefore be of great value and interest to this community.
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Rajneesh Kumar, Aseem Miglani and Rekha Rani
The purpose of this paper is to study the axisymmetric problem in a micropolar porous thermoelastic circular plate with dual phase lag model by employing eigenvalue approach…
Abstract
Purpose
The purpose of this paper is to study the axisymmetric problem in a micropolar porous thermoelastic circular plate with dual phase lag model by employing eigenvalue approach subjected to thermomechanical sources.
Design/methodology/approach
The Laplace and Hankel transforms are employed to obtain the expressions for displacements, microrotation, volume fraction field, temperature distribution and stresses in the transformed domain. A numerical inversion technique has been carried out to obtain the resulting quantities in the physical domain. Effect of porosity and phase lag on the resulting quantities has been presented graphically. The results obtained for Lord Shulman theory (L-S, 1967) and coupled theory of thermoelasticity are presented as the particular cases.
Findings
The variation of temperature distribution is similar for micropolar thermoelastic with dual (MTD) phase lag model and coupled theory of thermoelasticity. The variation is also similar for tangential couple stress for MTD and L-S theory but opposite to couple theory. The behavior of volume fraction field and tangential couple stress for L-S theory and coupled theory are observed opposite. The values of all the resulting quantities are close to each other away from the sources. The variation in tangential stress, tangential couple stress and temperature distribution is more uniform.
Originality/value
The results are original and new because the authors presented an eigenvalue approach for two dimensional problem of micropolar porous thermoelastic circular plate with dual phase lag model. A comparison of porosity, L-S theory and coupled theory of micropolar thermoelasticity is made. Such problem has applications in material science, industries and earthquake problems.
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Arvind Kumar and Praveen Ailawalia
The purpose of this paper is to study the thermal and mechanical disturbances in a piezo-electric microstretch thermoelastic medium due to the presence of ultra-short laser pulse…
Abstract
Purpose
The purpose of this paper is to study the thermal and mechanical disturbances in a piezo-electric microstretch thermoelastic medium due to the presence of ultra-short laser pulse as input heat source.
Design/methodology/approach
The medium is subjected to normal force, tangential force and thermal source. The solution of the problems is developed in terms of normal modes. Mathematical expressions have been obtained for normal stress, tangential stress, microstress, dielectric displacement vector and temperature change.
Findings
The numerically computed results are shown graphically. The effect of time and laser radius on temperature distribution is also shown graphically and comparison to theoretical results has been discussed. A mathematical model has been developed for the system of equations and various stress quantities have been analyzed. Some computer programs have also been written for this study. Two particular cases are also derived from the present investigation.
Originality/value
The effect of laser heat source is studied in piezo-electric microstretch thermoelastic medium. It is observed from the figures that the laser heat source has significant role on the values of coupled tangential stress.
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Rajneesh Kumar, Sanjeev Ahuja and S.K. Garg
The purpose of this paper is to study of propagation of plane wave and the fundamental solution of the system of differential equations in the theory of a microstretch…
Abstract
Purpose
The purpose of this paper is to study of propagation of plane wave and the fundamental solution of the system of differential equations in the theory of a microstretch thermoelastic diffusion medium in phase-lag models for the case of steady oscillations in terms of elementary functions.
Design/methodology/approach
Wave propagation technique along with the numerical methods for computation using MATLAB software has been applied to investigate the problem.
Findings
Characteristics of waves like phase velocity and attenuation coefficient are computed numerically and depicted graphically. It is found that due to the presence of diffusion effect, these characteristics get influenced significantly. However, due to decoupling of CD-I and CD-II waves from rest of other, no effect on these characteristics can be perceived.
Originality/value
Basic properties of the fundamental solution are established by introducing the dual-phase-lag diffusion (DPLD) and dual-phase-lag heat transfer (DPLT) models.
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