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1

Response of thermoelastic microbeam with double porosity structure due to pulsed laser heating

Kumar Rajneesh, Vohra Richa

Mechanics and Mechanical Engineering

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2019

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Vol. 23, nr 1

76--85

EN

The present investigation is concerned with vibration phenomenon of a homogeneous, isotropic thermoelastic microbeam with double porosity (TDP) structure induced by pulsed laser heating, in the context of Lord-Shulman theory of thermoelasticity with one relaxation time. Laplace transform technique has been applied to obtain the expressions for lateral deflection, axial stress, axial displacement, volume fraction field, and temperature distribution. The resulting quantities are recovered in the physical domain by a numerical inversion technique. Variations of axial displacement, axial stress, lateral deflection, volume fraction field, and temperature distribution with axial distance are depicted graphically to show the effect of porosity and laser intensity parameter. Some particular cases are also deduced.

2

Forced vibrations of a thermoelastic double porous microbeam subjected to a moving load

Kumar Rajneesh, Vohra Richa

Journal of Theoretical and Applied Mechanics

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2019

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Vol. 57 nr 1

155--166

EN

The present paper deals with forced vibrations of a homogeneous, isotropic thermoelastic double porous microbeam subjected to moving load, in context of Lord-Shulman theory of thermoelasticity with one relaxation time. The Laplace transform has been applied to obtain expressions for the axial displacement, lateral deflection, volume fraction field and temperature distribution. A numerical inversion technique has been used to recover the resulting quantities in the physical domain. Effects of velocity and time parameters are shown graphically by plotting axial displacement, lateral deflection, volume fraction field and temperature distribution against distance. Some particular cases are also deduced.

3

Modified Couple Stress Theory for Micro-Machined Beam Resonators with Linearly Varying Thickness and Various Boundary Conditions

Zenkour A. M.

Archive of Mechanical Engineering

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2018

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Vol. LXV, nr 1

43--64

EN

This article employs the classical Euler–Bernoulli beam theory in connection with Green–Naghdi’s generalized thermoelasticity theory without energy dissipation to investigate the vibrating microbeam. The microbeam is considered with linearly varying thickness and subjected to various boundary conditions. The heat and motion equations are obtained using the modified couple stress analysis in terms of deflection with only one material length-scale parameter to capture the size-dependent behavior. Various combinations of free, simply-supported, and clamped boundary conditions are presented. The effect of length-to-thickness ratio, as well as the influence of both couple stress parameter and thermoelastic coupling, are all discussed. Furthermore, the effect of reference temperature on the eigenfrequency is also investigated. The vibration frequencies indicate that the tapered microbeam modeled by modified couple stress analysis causes more responses than that modeled by classical continuum beam theory, even the thermoelastic coupled is taken into account.

4

Thermoelastic problem of an axially moving microbeam subjected to an external transverse excitation

Abouelregal A. E., Zenkour A. M.

Journal of Theoretical and Applied Mechanics

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2015

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Vol. 53 nr 1

167--178

EN

In this study, the problem of an axially moving microbeam subjected to sinusoidal pulse heating and an external transverse excitation is solved. The generalized thermoelasticity theory with one relaxation time is used to solve this problem. An analytical technique based on the Laplace transform is used to calculate the vibration of deflection and the temperature. The inverse of Laplace transforms are computed numerically using Fourier expansion techniques. The effects of the pulse-width of thermal vibration, moving speed and the transverse excitation are studied and discussed on the lateral vibration, temperature, displacement and bending moment of the beam.