Effect Of Phase-lags Research Articles

The Effect of Nonlocal Scale Value and Phase Lags on Thermoelastic Waves in a Multilayered LEMV/CFRP Composite Cylinder

In this study, the effect of nonlocal scale value and two phase lags on the free vibration of generalized thermoelastic multilayered LEMV (Linear Elastic Material with Voids)/CFRP (Carbon Fiber Reinforced Polymer) composite cylinder is studied using nonlocal form of linear theory of elasticity. The governing equation of motion is established in longitudinal axis and variable separation model is used to transform the governing equations into a system of differential equations. To investigate vibration analysis from frequency equations, the stress free boundary conditions are adopted at the inner, outer and interface boundaries. The graphical representation of the numerically calculated results for frequency shift, natural frequency, and thermoelastic damping is presented. A special care has been taken to inspect the effect of nonlocal parameter on the aforementioned quantities. The results suggest that the nonlocal scale and the phase lag parameters alter the vibration characteristics of composite cylinders significantly.

The Effect of Nonlocal Scale Value and Phase Lags on Thermoelastic Waves in a Multilayered LEMV/CFRP Composite Cylinder

The Effect of Nonlocal Scale Value and Phase Lags on Thermoelastic Waves in a Multilayered LEMV/CFRP Composite Cylinder

Effect of Nonlocal Elasticity and Phase Lags on the Magneto Thermoelastic Waves in a Composite Cylinder with Hall Current

In this study, the effect of nonlocal scale value and two phases lags on the free vibration of generalized magneto thermoelastic multilayered LEMV (Linear Elastic Material with Voids)/CFRP (Carbon Fiber Reinforced Polymer) composite cylinder is studied using nonlocal form of linear theory of elasticity. The governing equation of motion is established in longitudinal axis and variable separation model is used to transform the governing equations into a system of differential equations. To investigate vibration analysis from frequency equations, the stress free boundary conditions are adopted at the inner, outer and interface boundaries. The graphical representation of the numerically calculated results for frequency shift, natural frequency, and thermoelastic damping is presented. A special care has been taken to inspect the effect of nonlocal parameter on the aforementioned quantities. The results suggest that the nonlocal scale and the phase lag parameters alter the vibration characteristics of composite cylinders significantly.

On the thermo-vibrational response of multi-layer viscoelastic skin tissue to laser irradiation

This paper investigates temperature and vibration responses of human multi-layer skin tissue to laser irradiation. Due to the viscoelastic property of skin, a standard linear solid model known as the Zener model with two relaxation times with dual phase-lag heat conduction model has been used to describe the temperature and displacement in a one-dimensional form. The obtained differential equations have been discretized in the weak form to balance thermal and vibrational energies. The extracted time-dependent ordinary differential equations have been solved numerically by integration over time. The investigations are based on the effect of four relaxation times of temperature, heat, strain, and stress with laser effect in the form of a single step or repeated pulses on the behavior of the skin. By examining their results, the effect of phase lags has also been discussed, showing that the heat phase lag has a complex impact on thermal response and depends on the type of laser radiation. The phase lag of temperature reduces the temperature change rate, and the strain phase lag spreads the displacement at later times, gives inertia to the system, and dampens the system's vibration.

A thermoelastic model with higher order time derivatives for a crack in a rotating solid

This article represents a refined one-temperature thermoelastic model with higher order time derivatives and phase-lags for a Mode-I crack in a rotating fiber-reinforced solid. The crack is subjected to a stipulated temperature and normal stress. The exact expressions of displacement, temperature and stress components are obtained by normal mode analysis. Some generalized thermoelasticity theories are obtained as special cases. The convergency of the present refined model is tabulated and is compared with other theories. The variations of the temperature, displacements and stresses are presented graphically with the crack length to show the effect of phase-lags and thermal relaxation time through Refined-phase-lag (RPL), simple-phase-lag (SPL), Green-Naghdi (G-N) theory, Lord-Shulman (L-S) theory and the Coupled thermoelasticity (CTE) theory in the presence and absence of rotation.

One-dimensional numerical simulation of cavitation surge in pumping system considering cavity response delay

Cavitation instabilities such as rotating cavitation and cavitation surge often occur in high speed turbopumps. In the present study, numerical simulation of cavitation surge, which numerically solves the one-dimensional momentum and continuity equations with modelled dynamic cavitation characteristics, is conducted. The phase lag of cavity response against the inlet pressure and the suction flow rate variations is modeled in the form of the first-order lag system considering that the frequency of cavitation surge is small. Differently from linear stability analysis made in our previous study, the equations are solved in time domain with retaining some of non-linear terms. The method is validated through the comparison with the stability analysis. Then the effect of phase lags in dynamic cavitation characteristics is examined.

Effect of phase lags of moisture–heat flow on the hygrothermoelastic field of hollow cylinders with convective surfaces

In this article, by considering the Dufour effect and Soret effect, a hygrothermal coupling model based on phase delay of heat and moisture fluxes is established for convective surfaces. The convective surfaces are described by Robin boundary conditions. The Dirichlet boundary conditions (prescribed temperature and moisture on the surfaces) and Neumann boundary conditions (prescribed heat and moisture fluxes) are two extreme cases of the Robin conditions. Using Laplace transform, the effects of different relaxation times and moist-heat coupling on the temperature, moisture, and stress of the hollow cylinder are analyzed from two aspects of time and space. For convective boundary, the dependence of temperature, moisture, and stress on the phase lag of heat and moisture fluxes is examined. The results show that the temperature and moisture distributions along with the hygrothermal stress fields exhibit different behaviors, depending on the coefficient of Robin condition.

Effect of phase-lags on the transient waves in an axisymmetric functionally graded viscothermoelastic spherical cavity in radial direction

This paper aims to present the analysis of transient wave characteristics in a functionally graded viscothermoelastic infinite medium with spherical cavity in the context of generalized thermoelasticity. Continued series solution is used to solve simultanious differential equations for evaluating the field variables. Convergence of the series solution is implemented and investigated that the series of functions are absolutely and uniformly convergent. The formal solution for the field variables are obtained analytically and represented graphically. The effect of grading index and different theories of generalized thermoelasticity are also shown graphically to examine the behavior of the variations of the field variables.

P, T, and SV wave propagation at the interface between solid–liquid media with magnetic field and initial stress in the context of three-phase-lag model

ABSTRACTIn this article, the problem of reflection and refraction of thermoelastic wave at a solid–liquid interface in the presence of magnetic field and initial stress has been investigated. The problem has been solved in the context of three-phase-lag model of thermoelasticity. The appropriate expressions to find the amplitude ratios for all the three cases of p-wave incidence, SV-wave incidence, and thermal wave incidence have been developed. However, the ratios of amplitudes of reflected and refracted waves to that of incident wave are computed numerically for earth's crust-water interface, for incident SV wave only, considering the initial stress to be tensile as well as compressional both. The obtained results have been presented graphically to show the effect of phase lags, magnetic field, and initial stress.

Effect of phase-lags on Rayleigh wave propagation in initially stressed magneto-thermoelastic orthotropic medium

• Thermal boundary condition for generalized thermoelasicity is developed. • Different secular equations are derived which agree with existing literature. • Path of surface particles during Rayleigh wave propagation in orthotropic medium is elliptical. • Rayleigh wave velocity increases with the increase of wave number, initial stress and magnetic field. • Attenuation coefficient decreases with the increase of wave number, initial stress and magnetic field. The present article deals with Rayleigh surface wave propagation in homogeneous magneto-thermoelastic orthotropic medium. Effect of initial stress and magnetic field on Rayleigh waves is studied in the context of three-phase-lag model of generalized thermoelasticity. The normal mode analysis is used to obtain the exact expressions for the displacement components, stresses and temperature distribution. Various frequency equations are derived and compared with the existing literature. The path of surface particles is elliptical during Rayleigh wave propagation. Effect of phase-lags on Rayleigh wave velocity, attenuation coefficient and specific loss are presented graphically. It is observed from graphical presentation that the effect of magnetic field and initial stress on different wave characteristics is pronounced.

Elastodynamic interactions of laser pulse in microstretch thermoelastic mass diffusion medium with dual phase lag

The aim of the present investigation is to study the effects of laser heat source and phase lags on a microstretch thermoelastic mass diffusion medium including dual phase lag model. The normal mode analysis technique has been adopted to obtain the components of displacement, microrotation, microstress, mass concentration and temperature distribution due to the presence of ultra-laser heat source. The numerical computation has been performed (using Matlab software) on the resulting quantities. The computed numerical results are shown graphically to depict the effect of laser heat source and diffusion phase-lags. Some particular cases of interest are also deduced from the present investigation.

Response of thermoelastic functionally graded beam due to ramp type heating in modified couple stress with dual-phase-lag model

PurposeThe purpose of this paper is to investigate the thermoelastic functionally graded beam in a modified couple stress theory subjected to a dual-phase-lag model.Design/methodology/approachThe governing equations are solved by using the Euler-Bernoulli beam assumption and the Laplace transform technique. The lateral deflection, temperature change, displacement component, axial stress and thermal moment of the beam are obtained by ramp type heating in the transformed domain. A general algorithm of the inverse Laplace transform is developed to recover the results in a physical domain.FindingsThe lateral deflection, temperature change, displacement component, axial stress and thermal moment of the beam are computed numerically and presented graphically to show the effect of ramp time parameter and phase lags of heating.Originality/valueComparisons are made in the absence and presence of coupled dual-phase-lag thermoelastic and coupled thermoelastic L-S theories and also different values of ramp type parameter.

Generalized Two Temperatures Thermoelasticity of Micropolar Porous Circular Plate with Three Phase Lag Model

AbstractThe present study is to focus on the two dimensional problem of micropolar porous circular plate with three phase lag model within the context of two temperatures generalized thermoelasticity theory. The problem is solved by applying Laplace and Hankel transforms after using potential functions. The expressions of displacements, microrotation, volume fraction field, temperature distribution and stresses are obtained in the transformed domain. To show the utility of the approach, normal force and thermal source are taken. The numerical inversion techniques of transforms have been carried out in order to evaluate the resulting quantities in the physical domain. Finally, the resulting quantities are depicted graphically to show the effect of porosity, two temperatures and phase lags.

Effects of phase-lags in a thermoviscoelastic orthotropic continuum with a cylindrical hole and variable thermal conductivity

This article presents an analytical solution for the effect of phase-lags on a generalized plane strain thermoviscoelastic orthotropic medium with a cylindrical cavity subjected to a thermal shock from varying heat. It is assumed that the cylindrical cavity is made of Kelvin–Vogt type material. The general solutions for field quantities are obtained using the method of Laplace transforms. The results are graphically presented to illustrate the effect of phase-lags, viscoelasticity and variability of thermal conductivity on the studied fields. Comparisons are also presented with those in the absence of viscosity and variability of thermal conductivity.

Effect of phase-lags on Rayleigh wave propagation in thermoelastic medium with mass diffusion

Purpose– The purpose of this paper is to study the propagation of Rayleigh waves in thermoelastic medium with mass diffusion.Design/methodology/approach– The field equations for the linear theory of homogeneous isotropic thermoelastic diffusion medium are taken into consideration by using dual-phase-lag heat transfer (DPLT) and dual-phase-lag diffusion (DPLD) models. Using the potential functions and harmonic wave solution, three coupled dilatational waves and a shear wave is obtained. After developing mathematical formulation, the dispersion equation is obtained, which results to be complex and irrational. This equation is converted into a polynomial form of higher degree.Findings– From the polynomial equation, Rayleigh wave root is found. The secular equation is resolved into a polynomial form to find the roots and therefore to find the existence and propagation of Rayleigh wave. The existence of Rayleigh wave in the assumed model depends on the values of various parameters involved in the secular equation. These roots are resolved for phase velocity and attenuation of the inhomogeneous propagation of Rayleigh wave. Behavior of particle motion of these waves inside and at the surface of the thermoelastic medium with mass diffusion is studied. Particular cases of the interest are also deduced from the present investigation.Originality/value– Governing equations corresponding to DPLT and DPLD models of thermoelastic diffusion are formulated to study the wave propagation and their dependence on various material parameters. In this paper effects of thermal and diffusion phase lags on the phase velocity, attenuation and on particle paths are observed and depicted graphically.

On the Generalized Thermoelasticity Problem for an Infinite Fibre-Reinforced Thick Plate under Initial Stress

AbstractIn this paper, the generalized thermoelasticity problem for an infinite fiber-reinforced transversely-isotropic thick plate subjected to initial stress is solved. The lower surface of the plate rests on a rigid foundation and temperature while the upper surface is thermally insulated with prescribed surface loading. The normal mode analysis is used to obtain the analytical expressions for the displacements, stresses and temperature distributions. The problem has been solved analytically using the generalized thermoelasticity theory of dual-phase-lags. Effect of phase-lags, reinforcement and initial stress on the field quantities is shown graphically. The results due to the coupled thermoelasticity theory, Lord and Shulman’s theory, and Green and Naghdi’s theory have been derived as limiting cases. The graphs illustrated that the initial stress, the reinforcement and phase-lags have great effects on the distributions of the field quantities.

Plane wave propagation in an anisotropic dual-phase-lag thermoelastic diffusion medium

Purpose– The purpose of this paper is to depict the effect of thermal and diffusion phase-lags on plane waves propagating in thermoelastic diffusion medium with different material symmetry. A generalized form of mass diffusion equation is introduced instead of classical Fick's diffusion theory by using two diffusion phase-lags, one phase-lag of diffusing mass flux vector, represents the delayed time required for the diffusion of the mass flux and the other phase-lag of chemical potential, represents the delayed time required for the establishment of the potential gradient. The basic equations for the anisotropic thermoelastic diffusion medium in the context of dual-phase-lag heat transfer (DPLT) and dual-phase-lag diffusion (DPLD) models are presented. The governing equations for transversely isotropic and isotropic case are also reduced. The different characteristics of waves like phase velocity, attenuation coefficient, specific loss and penetration depth are computed numerically. Numerically computed results are depicted graphically for anisotropic, transversely isotropic and isotropic medium. The effect of diffusion and thermal phase-lags are shown on the different characteristic of waves. Some particular cases of result are also deduced from the present investigation.Design/methodology/approach– The governing equations of thermoelastic diffusion are presented using DPLT model and a new model of DPLD. Effect of phase-lags of thermal and diffusion is presented on different characteristic of waves.Findings– The effect of diffusion and thermal phase-lags on the different characteristic of waves is appreciable. Also the use of diffusion phase-lags in the equation of mass diffusion gives a more realistic model of thermoelastic diffusion media as it allows a delayed response between the relative mass flux vector and the potential gradient.Originality/value– Introduction of a new model of DPLD in the equation of mass diffusion.

Numerical study on triple layer skin tissue freezing using dual phase lag bio-heat model

The present article proposes dual-phase lag (DPL) bio-heat model in triple layer skin tissue for freezing procedure during cryosurgery with non-ideal property of tissue, metabolism and blood perfusion. The enthalpy formulation and the finite difference schemes are used to evaluate temperature distribution, solidus and liquidus interfaces in soft skin tissue during the freezing process. The effect of phase lags of heat flux and temperature gradient are also discussed in this study. It is mentioned that the different values of phase lags of heat flux and temperature gradient have important effect on temperature distribution, liquidus and solidus interfaces within the skin tissue.