This article deals with the study of density parameter in a disk made of cadmium, magnesium and beryl material, by using generalised strain measure. The mathematical model is based on stress-strain relation and equilibrium equation. Analytical solutions are presented for the disk made of cadmium, magnesium and beryl material. Effects of different pertinent parameters (i.e., density and angular speed) are considered for the disk made of cadmium, magnesium and beryl material. The behaviour of stress distribution and angular speed are investigated. From the obtained results, it is noticed that cadmium material disk requires a higher value of angular speed to yield at the internal surface in comparison to the disk made of magnesium/beryl material.

The paper deals with the analytical solution of transitional stresses in thin rotating disc composed of piezoelectric material under temperature and internal pressure. The stresses are evaluated in the rotating disc by using transition theory of Seth. The electric displacement relations and stresses are computed by using stress strain relations. The non-homogeneous differential equation is derived by substituting the obtained relations into the equilibrium equation. The formulated differential equation is solved with specified boundary conditions, applied pressure, electric displacement and stresses. Obtained results are exhibited graphically, analysed numerically and it is then concluded that transversely isotropic beryl is better than transversely isotropic magnesium material and transversely isotropic piezoelectric materials BaTiO4 and PZT-4.

The article deals with the comparative study of creep analysis in a rotating disk made of rubber/copper material and fitted with rigid shaft. The effects of different pertinent parameters (i.e., angular speed and density) are considered for the rotating disk of rubber/steel material. The behaviour of creep stress/strain rate distribution, and density rise are investigated. From the obtained results, it is noticed that the radial stress requires a maximum value at the inner surface of the disk fitted with rigid shaft made of rubber material in comparison to the disk made of copper material. The strain rates must be decreased with increasing density parameter. Results have been discussed numerically and graphically.

The article deals with the comparative study of creep analysis in a rotating disk made of rubber/copper material and fitted with rigid shaft. The effects of different pertinent parameters (i.e., angular speed and density) are considered for the rotating disk of rubber/steel material. The behaviour of creep stress/strain rate distribution, and density rise are investigated. From the obtained results, it is noticed that the radial stress requires a maximum value at the inner surface of the disk fitted with rigid shaft made of rubber material in comparison to the disk made of copper material. The strain rates must be decreased with increasing density parameter. Results have been discussed numerically and graphically.

This article deals with the study of thermal stress distribution in a tube made of natural rubber/polyurethane material and subjected to internal pressure and mechanical load. From the obtained results, it is noticed that natural rubber material of the tube requires higher pressure to yield at the internal surface in comparison to tube made of polyurethane, for the initial yielding stage. Moreover, the tube of natural nal surface as compared to the tube of polyurethane matematerial is more comfortable than that of polyurethane.

Thermal creep analysis of spherical shell made up of functionally graded material is done under influence of internal and external pressure. The strain measures are used in generalized form to solve complex situation of creep in shell. Creep stresses are examined along the internal and external part of shell by using generalized strain measure. The influence of linear to nonlinear measure on shell is shown. The results are numerically derived and shown graphically.

The effect of two temperatures on the elastic properties of a generalized microstretch thermoelastic solid half-space has been investigated. The Green-Naghdi (GN) theory of thermoelasticity is adopted in the present research. The exact solutions of the problem are obtained in terms of the normal modes. Using the normal mode analysis technique, the mathematical expressions of displacement components, normal stress, couple tangential stress, tangential stress, micro stress and the temperature distribution are derived.

A thick-walled spherical shell made up of homogeneous material subjected to combined effect of internal and external pressure has been analysed. The objective of this paper is to provide guidance in designing the spherical shell so that collapse of spherical shell due to internal and external pressure can be avoided. The problem is based on elastic-plastic transition phenomenon and the solution has been obtained by using the concept of generalized strain measures and Seth's transition theory. The transition theory does not assume adhoc assumptions like incompressibility and yield conditions. The radial and circumferential stresses have been evaluated at the internal surface of the spherical shell for compressible as well as incompressible materials. It has been observed that the spherical shell of incompressible material requires a high pressure to start initial yielding in the shell as compared to the spherical shell of a compressible material. The results are derived numerically and shown graphically.

In the present discussion, the plane strain deformation due to laser pulse heating in a thermoelastic microelongated solid has been discussed.The analytic expressions for displacement component, force stress, temperature distribution and micro-elongation have been derived.The effect of pulse rise time and micro-elongation on the derived components have been depicted graphically.

This paper studies the propagation of shear waves in a composite structure consisting of a piezoelectric layer perfectly bonded over a micropolar elastic half space. The general dispersion equations for the existence of shear waves are obtained analytically in the closed form. Some particular cases have been discussed and in one special case the relation obtained is in agreement with existing results of the classical –Love wave equation. The micropolar and piezoelectric effects on the phase velocity are obtained for electrically open and mechanically free structure. To illustrate the utility of the problem numerical computations are carried out by considering PZT-4 as a piezoelectric and aluminium epoxy as micropolar elastic material. It is observed that the micropolarity present in the half space influence the phase velocity significantly in a particular region. The micropolar effects on the phase velocity in the piezoelectric coupled structure can be used to design high performance acoustic wave devices.

Originalni naučni rad / Original scientific paper UDK /UDC: 537.32 Rad primljen / Paper received: 18.03.2019 Adresa autora / Author's address: 1) Depart. of Mathematics, Guru Nanak Dev Engg. College, Ludhiana, Punjab, India email: dspathania@gndec.ac.in 2) AMSSS Ukalana (Hisar), Department of Secondary Education, Haryana, India 3) GSSS Durjanpur (Hisar), Department of Secondary Education Haryana, India 4) Chandigarh University, Gharuan, India

The purpose of this paper is to study the thermo-mechanics of magneto-micropolar thermoelastic half-space considering the effect of Hall current, input heat source and rotation subjected to input ultra-laser heat source. The micropolar theory of thermoelasticity by Eringen (1966) has been used to investigate the problem. Normal mode analysis technique has been used to solve the resulting non-dimensional coupled field equations to obtain displacement, stress components and temperature distribution.

This study is concerned with the thermo-mechanical interactions of ultra-short laser pulse as input heat source with homogeneous isotropic microstretch-thermoelastic solid half-space with microtemperatures. The medium is subjected to normal force and thermal source. Integral transform (Laplace transform and Fourier transform) technique has been applied to the basic equations to solve the problem. Expressions have been obtained for normal stress, tangential stress, microstress and temperature distribution in the transferred domain. The numerically computed results are shown graphically. Some special cases are also deduced from the present investigation.

This paper deals with the propagation of Rayleigh waves in a micropolar thermoelastic half space with impedance boundary conditions. The boundary of the half space is thermally insulated / isothermal and it is assumed that normal traction, shear traction and shear couple traction at the surface, varies linearly with normal, tangential components of displacement and microrotation respectively. The secular equation for Rayleigh wave with impedance boundary conditions is obtained and this equation is in agreement with the classical secular equation for elastic solid with traction free boundary conditions when micropolar, thermal and impedance parameters are removed. The non-dimensional speed of Rayleigh wave is computed as a function of impedance parameters and presented graphically for a particular micropolar thermoelastic material.

A two-dimensional problem in an infinite microstretch thermoelastic solid with microtemperatures subjected to a mechanical source is studied. The medium is rotating with a uniform angular velocity ??. The normal mode analysis is used to obtain the exact expressions for the component of normal displacement, microtemperature, normal force stress, microstress tensor, temperature distribution, heat flux moment tensor and tangential couple stress. The effect of microrotation and stretch on the considered variables are illustrated graphically.

This paper presents nonlinear deformation behaviour of non-homogeneous spherical shell examined under pressure by using Seth's transition theory. It has been seen that for increased material compressibility in thickness direction, the circumferential stress in the spherical shell reaches maximum at the external surface, but is reverse in the case of a deceasing compressibility in the thickness direction. The spherical shell of non-homogeneous material (non-homogeneity increases radially) is on the safer side of design. Hence, the more use of non-homogeneous material (non-homogeneity increases radially) may be beneficial for manufacturing spherical shells as they provide longer service life than shells of homogeneous material under identical conditions.

The present investigation deals with the two-dimensional deformation in a thermoelastic micropolar solid with cubic symmetry at the interface of the semi-infinite semiconducting medium under photothermal theory. A mechanical force is applied along the interface. The analytic expressions for the components of normal displacement, temperature distribution, normal force stress, and tangential couple stress for a thermoelastic micropolar solid with cubic symmetry have been obtained using normal mode analysis technique. The effect of anisotropy, microrotation, and thermoelasticity on the derived components have been depicted graphically.

The purpose of this paper is to study the variations in temperature, radial and normal displacement, normal stress, shear stress and couple stress in a micropolar thermoelastic solid in the context of fractional order theory of thermoelasticity. Eigen value approach together with Laplace and Hankel transforms are employed to obtain the general solution of the problem. The field variables corresponding to different fractional order theories of thermoelasticity have been obtained in the transformed domain. The general solution is applied to an infinite space subjected to a concentrated load at the origin. To obtained solution in the physical domain numerical inversion technique has been applied and numerically computed results are depicted graphically to analyze the effects of fractional order parameter on the field variables.

The purpose of this paper is to present study of thermal creep stress and strain rates in non-homogeneous spherical shell by using Seth's transition theory. Seth's transition theory is applied to the problem of creep stresses and strain rates in non-homogeneous spherical shell under steady-state temperature. Neither the yield criterion nor the associated flow rule is assumed here. With the introduction of thermal effect, the values of circumferential stress decrease at the external surface as well as at the internal surface of the spherical shell for different values of non-homogeneity. It means that the temperature dependent materials minimize the possibility of a fracture at the internal surface of the spherical shell. The model proposed in this paper is used commonly in the design of chemical and oil plants, industrial gas and steam turbines, high speed structures involving aerodynamic heating.

Abstract The present study deals with two dimensional deformation, due to internal heat source in a thermoelastic microelongated solid. A mechanical force is applied along the interface of elastic half space and thermoelastic microelongated half space. The problem is in the context of Green Lindsay (GL) theory. The analytic expressions for displacement component, normal force stress, temperature distribution and microelongation have been derived. The effect of internal heat source and microelongation on the derived components have been depicted graphically.