Gravitational effect and initial stress on generalized magneto-thermo-microstretch elastic solid for different theories

PurposeThe purpose of this paper is to study the effect of rotation and initial stress on magneto-thermoelastic material with voids heated by a laser pulse heating.Design/methodology/approachThe analytical method used was the normal mode analysis technique.FindingsNumerical results for the physical quantities were presented graphically and analyzed. The graphical results indicate that the effect of rotation, initial stress and magnetic fields are observable physical effects on the thermoelastic material with voids heated by a laser pulse. Comparisons are made with the results in the absence and the presence of the physical operators, also at various times.Originality/valueIn the present work, the authors shall investigate the effect of the rotation, initial stress, magnetic field and laser pulse on thermoelastic material with voids subjected to a laser pulse heating acting as a thermal shock. A comparison is also made between the two types (types II and III) of Green-Naghdi theory in the absence and the presence of the physical operators. Such problems are very important in many dynamical systems.

Generalized thermo-microstretch elastic medium with temperature dependent properties for different theories

In the present paper, the theory of multi‐phase‐lags with fractional derivative heat transfer thermoelasticity was used to study the wave propagation on a nonlocal fiber‐reinforced thermoelastic medium. The exact expressions for the displacement components, temperature, and stress components are obtained by using the Fourier and Laplace transforms. The comparisons are shown graphically to explore the effects of rotation, initial stress and fractional order parameters as well as a nonlocal parameter on different physical quantities. Numerical computations are carried out with the help of Matlab software.

The effect of initial stress on the propagation behavior of SH waves in piezoelectric coupled plates

The present study is attempted to analyze the thermoelastic interactions in a homogeneous isotropic electro-microstretch semi-space caused by mechanical source acting on the initially stressed surface. The problem is treated on the basis of two-temperature thermoelasticity without energy dissipation proposed by Youssef. Normal mode analysis is applied to derive the exact expressions for displacement components, force stresses, couple stress, microstress, conductive temperature, thermodynamic temperature and electric field. Numerical computations have been performed for magnesium crystal material to depict the response of mechanical source in the medium for thermally insulated boundary. Some comparisons have been made in figures to estimate the effects of two-temperature parameter and initial stress.

Rayleigh waves in a magnetoelastic half-space of orthotropic material under influence of initial stress and gravity field

In this paper, the nonlinear free vibrations of thin symmetric and non-symmetric cross-ply composite plates subjected to biaxial initial stresses are investigated. Because of their excellent properties such as specific strength and specific stiffness, composite plates have wide applications in aerospace and mechanical structures. Based on Von-Karman's strain-displacement relations and using Galerkin method, the nonlinear differential equation of free vibrations of initially stressed composite plate is obtained. This nonlinear equation is solved using two different analytical perturbation methods, namely method of multiple scales (MTS) and homotopy perturbation method (HPM), to analyze the nonlinear vibrations of initially stressed cross-ply composite plates. Effects of tensile and compressive biaxial initial stresses, initial vibration amplitude, thickness, and aspect ratios of the composite plates on the frequency behavior are investigated. The validity of the results is confirmed by making a comparison with those reported in the literature. According to the results, both analytical solutions show increasing trends for natural frequency parameters by increasing normal initial stresses. Regardless of the value of initial biaxial stresses, for both symmetric and non-symmetric plates, the results of MTS and HPM are in close agreement for the smallest initial amplitude. However, for compressive initial stresses, by increasing initial amplitude ratios, the discrepancies between the results of HPM and MTS increase for symmetric and non-symmetric plates. Although HPM includes less computational effort (smaller length of formulation) than MTS, the linear-to-nonlinear frequency ratios obtained using MTS method become closer to those obtained by HPM as initial vibration amplitude is decreased and initial stress is increased.

In the present paper, the two different theories (coupled theory and Green–Lindsay theory with two relaxation times) are applied to study the deformation of a generalized piezo-thermoelastic rotating medium under the influence of magnetic field. The normal mode analysis is used to obtain the expressions for the displacement components, the temperature, the stress, the strain components, the electric potential and the electric displacements. Numerical results for the field quantities are given in the physical domain and illustrated graphically. Comparisons are made with the results predicted by coupled and Green–Lindsay theories in the presence and absence of rotation as well as magnetic field.

Effect of initial stresses on dispersion relation of transverse waves in a piezoelectric layered cylinder

On the effect of initial stress in a 3D half-space on superimposed harmonic stresses

Influence of initial static stress on the dynamic properties of concrete

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.

A general model of the equations of the Lord—Şulman theory including one relaxation time and the Green—Lindsay theory with two relaxation times, as well as the classical dynamical coupled theory, are applied to the study of the influence of reinforcement on the total deformation for an infinite space weakened by a finite linear opening mode-I crack. We study the influence of reinforcement on the total deformation of rotating thermoelastic half-space and their interaction with each other. The material is homogeneous isotropic elastic half space. The crack is subjected to prescribed temperature and stress distributions. The normal mode analysis is used to obtain the exact expressions for displacement components, force stresses, and temperature. The variations of the considered variables with the horizontal distance are illustrated graphically. Comparisons are made with the results obtained in the three theories with and without rotation. A comparison is also made between the two theories for different depths.

Residual stress by repair welds in a pipe weld is computed using the thermal elastic-plastic analysis. Weld bond and heat-affected zone of a butt-welded joint is gouged and then deposited by weld metal in repair process. Heat source is synchronously moved with the deposition of the finite-element as the weld deposition. The effects of initial stress, heat input, and weld length on residual stress distribution are studied from the organic results of numerical analysis. Initial residual stress before repair weld has no influence on the residual stress after repair treatment near weld metal, because the initial stress near weld metal releases due to high temperature of repair weld and then stress by repair weld regenerates. Heat input has an effect for residual stress distribution, for not its magnitude but distribution zone. Weld length should be considered for reducing the magnitude of residual stress in the edge of weld bead; short bead induces high tensile residual stress.

The present paper is concerned with the propagation of shear waves in an isotropic, viscoelastic, heterogeneous layer lying over a homogeneous half space under initial stress. For the layer the inhomogeneity associated to rigidity, internal friction and density is assumed to be linear function of depth. The dispersion equation of shear waves has been obtained in closed form. The dimensionless phase velocity and damping velocity have been plotted against dimensionless wave number for different values of inhomogeneity parameter and initial stress. The effects of inhomogeneity and initial stress have been shown in the dispersion curves.