Influence of various sources in micropolar thermoelastic medium with voids

Kumar, Rajneesh,Ailawalia, Praveen Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.31 No.6

The present problem is concerned with the study of deformation of micropolar thermoelastic medium with voids under the influence of various sources acting on the plane surface. The analytic expressions of displacement components, force stress, couple stress, change in volume fraction field and temperature distribution are obtained in the transformed domain for Lord-Shulman (L-S) theory of thermoelasticity after applying the integral transforms. A numerical inversion technique has been applied to obtain the solution in the physical domain. The numerical results are presented graphically. Some useful particular cases have also been deduced.

Vibration analysis of wave motion in micropolar thermoviscoelastic plate

Kumar, Rajneesh,Partap, Geeta Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.39 No.6

The aim of the present article is to study the micropolar thermoelastic interactions in an infinite Kelvin-Voigt type viscoelastic thermally conducting plate. The coupled dynamic thermoelasticity and generalized theories of thermoelasticity, namely, Lord and Shulman's and Green and Lindsay's are employed by assuming the mechanical behaviour as dynamic to study the problem. The model has been simplified by using Helmholtz decomposition technique and the resulting equations have been solved by using variable separable method to obtain the secular equations in isolated mathematical conditions for homogeneous isotropic micropolar thermo-viscoelastic plate for symmetric and skew-symmetric wave modes. The dispersion curves, attenuation coefficients, amplitudes of stresses and temperature distribution for symmetric and skew-symmetric modes are computed numerically and presented graphically for a magnesium crystal.

Vibration analysis of wave motion in micropolar thermoviscoelastic plate

Rajneesh Kumar,Geeta Partap 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.39 No.6

The aim of the present article is to study the micropolar thermoelastic interactions in an infinite Kelvin-Voigt type viscoelastic thermally conducting plate. The coupled dynamic thermoelasticity and generalized theories of thermoelasticity, namely, Lord and Shulman’s and Green and Lindsay’s are employed by assuming the mechanical behaviour as dynamic to study the problem. The model has been simplified by using Helmholtz decomposition technique and the resulting equations have been solved by using variable separable method to obtain the secular equations in isolated mathematical conditions for homogeneous isotropic micropolar thermo-viscoelastic plate for symmetric and skew-symmetric wave modes. The dispersion curves, attenuation coefficients, amplitudes of stresses and temperature distribution for symmetric and skew-symmetric modes are computed numerically and presented graphically for a magnesium crystal.

Rayleigh waves in anisotropic magnetothermoelastic medium

Kumar, Rajneesh,Sharma, Nidhi,Lata, Parveen,Abo-Dahab, S.M. Techno-Press 2017 Coupled systems mechanics Vol.6 No.3

The present paper is concerned with the investigation of Rayleigh waves in a homogeneous transversely isotropic magnetothermoelastic medium with two temperature, in the presence of Hall current and rotation. The formulation is applied to the thermoelasticity theories developed by Green-Naghdi theories of Type-II and Type-III. Secular equations are derived mathematically at the stress free and thermally insulated boundaries. The values of Determinant of secular equations, phase velocity and Attenuation coefficient with respect to wave number are computed numerically. Cobalt material has been chosen for transversely isotropic medium and magnesium material is chosen for isotropic solid. The effects of rotation, magnetic field and phase velocity on the resulting quantities and on particular case of isotropic solid are depicted graphically. Some special cases are also deduced from the present investigation.

Response of temperature dependence of an elastic modulus in microstretch generalized thermoelasticity

Rajneesh Kumar,Rajani Rani Gupta 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.5

Laplace-Fourier transform techniques are used to investigate the interaction caused by mechanical, thermal and microstress sources in a generalized thermomicrostretch elastic medium with temperature-dependent mechanical properties. The modulus of elasticity is taken as a linear function of reference temperature. The integral transforms are inverted using a numerical technique to obtain the normal stress, tangential stress, tangential couple stress, microstress and temperature distribution. Effect of temperature dependent modulus of elasticity and thermal relaxation times have been depicted graphically on the resulting quantities. Comparisons are made with the results predicted by the theories of generalized thermoelasticity. Some particular cases are also deduced from the present investigation.

Influence of various sources in micropolar thermoelastic medium with voids

Rajneesh Kumar,Praveen Ailawalia 국제구조공학회 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.31 No.6

The present problem is concerned with the study of deformation of micropolar thermoelastic medium with voids under the influence of various sources acting on the plane surface. The analytic expressions of displacement components, force stress, couple stress, change in volume fraction field and temperature distribution are obtained in the transformed domain for Lord-Shulman (L-S) theory of thermoelasticity after applying the integral transforms. A numerical inversion technique has been applied to obtain the solution in the physical domain. The numerical results are presented graphically. Some useful particular cases have also been deduced.

Dynamic problem of generalized thermoelastic diffusive medium

Rajneesh Kumar,Tarun Kansal 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.1

The equations of generalized thermoelastic diffusion, based on the theory of Lord and Shulman with one relaxation time, are derived for anisotropic media with rotation. The variational principle and reciprocity theorem for the governing equations are derived. The propagation of leaky Rayleigh waves in a viscous fluid layer overlying a homogeneous isotropic, generalized thermoelastic diffusive halfspace with rotating frame of reference is studied.

Thermomechanical deformation in porous generalized thermoelastic body with variable material properties

Kumar, Rajneesh,Devi, Savita Techno-Press 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.34 No.3

The two-dimensional deformation of a homogeneous, isotropic thermoelastic half-space with voids with variable modulus of elasticity and thermal conductivity subjected to thermomechanical boundary conditions has been investigated. The formulation is applied to the coupled theory(CT) as well as generalized theories: Lord and Shulman theory with one relaxation time(LS), Green and Lindsay theory with two relaxation times(GL) Chandrasekharaiah and Tzou theory with dual phase lag(C-T) of thermoelasticity. The Laplace and Fourier transforms techniques are used to solve the problem. As an application, concentrated/uniformly distributed mechanical or thermal sources have been considered to illustrate the utility of the approach. The integral transforms have been inverted by using a numerical inversion technique to obtain the components of displacement, stress, changes in volume fraction field and temperature distribution in the physical domain. The effect of dependence of modulus of elasticity on the components of stress, changes in volume fraction field and temperature distribution are illustrated graphically for a specific model. Different special cases are also deduced.

Vertical-slate-like MoS2 nanostructures on 3D-Ni-foam for binder-free, lowcost, and scalable solid-state symmetric supercapacitors

Rajneesh Kumar Mishra,Ajay Kumar Kushwaha,김승엽,서승기,진성훈 한국물리학회 2019 Current Applied Physics Vol.19 No.1

Here, we report binder-free vertical-slate-like MoS2 nanostructures on 3D-Ni-Foam (VSL-MoS2@3D-Ni foam) for low-cost high-performance solid-state symmetric supercapacitors (SSCs). The cost-effective, ecofriendly and scalable solvothermal method and its direct incorporation of VSL-MoS2@3D-Ni-foam yield SSCs with excellent electrochemical properties with a wide potential window of 1.0 V. Furthermore, high specific capacitance of 34.1 F g−1 at a current density of 1.3 A g−1, an energy density of 4.7Wh kg−1 at a high-power density of 650Wkg−1, and excellent stability with ∼82.5% capacitance retention after 10,000 cycles were demonstrated even for SSCs with a binder free MoS2 electrodes on 3D-Ni-foam. These excellent features of the SSCs with VSLMoS2@ 3D-Ni-foam substantiate their potential opportunity for future energy applications.

Effects of Hall current in a transversely isotropic magnetothermoelastic with and without energy dissipation due to normal force

Rajneesh Kumar,Nidhi Sharma,Parveen Lata 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.57 No.1

This investigation is concerned with the disturbances in a homogeneous transversely isotropic thermoelastic rotating medium with two temperature, in the presence of the combined effects of Hall currents and magnetic field due to normal force of ramp type. The formulation is applied to the thermoelasticity theories developed by Green-Naghdi Theories of Type-II and Type-III. Laplace and Fourier transform technique is applied to solve the problem. The analytical expressions of displacements, stress components, temperature change and current density components are obtained in the transformed domain. Numerical inversion technique has been applied to obtain the results in the physical domain. Numerically simulated results are depicted graphically to show the effects of Hall current and anisotropy on the resulting quantities. Some special cases are also deduced from the present investigation.