Presence Of Thermal Environment Research Articles

On nonlinear damping effects with nonlinear temperature-dependent properties for an axial thermo-viscoelastic rod

The present manuscript develops a new axisymmetric model of thermo-viscoelastic rods to account for uniform temperature effects and nonlinear terms, which are induced by Kelvin–Voigt damping. A fundamental relationship between the damping of viscoelastic material and nonlinear geometry are researched through the application of Galerkin and multiple scale (MS) methods to the new model. Then, the MSM-based solutions are confirmed with a numerical integration method, and a good agreement between the approximate analytical and numerical results is observed. Free axial vibrations based on the standard linear solid model in uniform thermal rises with nonlinear material properties as a function of temperature is considered. The temperature of the viscoelastic rod remains constant under conditions of uniform temperature rise. Studying the behavior of the dynamic system in the presence of uniform temperatures increases the effect of nonlinear damping on its vibration behavior. Approximate analytical results are presented for use as a reference point in future analysis of nonlinear thermo-viscoelastic rods with a weak hardening system. Also, the results of this research can be useful and practical for finding the modal damping ratio of the system as well as the dynamic analysis of damping in the presence of thermal environment.

Nonlinear vibration of stiffened multilayer FG cylindrical shells with spiral stiffeners rested on damping and elastic foundation in thermal environment

Abstract This paper presents the nonlinear vibration of multilayer FG cylindrical shells reinforced by spiral FG stiffeners surrounded by damping and elastic foundation in thermal environment. The primary, superharmonic and subharmonic resonances of spiral stiffened multilayer FG cylindrical shell are analyzed. It is assumed that the material properties are dependent to temperature. The linear elastic foundation is based on the Winkler and Pasternak model. In order to model the stiffeners, the technique of smeared stiffener is utilized. With regard to classical plate theory of shells, von Karman equation and Hook law, the relations of stress-strain is derived for shell and stiffeners. According to the Galerkin method, the discretized motion equation is obtained. The primary, superharmonic and subharmonic resonances in presence of thermal environment are analyzed by using the method of multiple scales. The influence of the material parameters, temperature, elastic foundation and various geometrical characteristics on the primary, superharmonic and subharmonic resonances is investigated.

Stability and dynamic analysis of partially cracked thin orthotropic microplates under thermal environment: an analytical approach

An analytical model is proposed to analyze the vibration and buckling problem of partially cracked thin orthotropic microplate in the presence of thermal environment. The differential governing equation for the cracked plate is derived using the classical plate theory in conjunction with the strain gradient theory of elasticity. The crack is modeled using appropriate crack compliance coefficients based on the simplified line spring model. The influence of thermal environment is incorporated in governing equation in form thermal moments and in-plane compressive forces. The governing equation for cracked plate has been solved analytically to get fundamental frequency and central deflection of plate. To demonstrate the accuracy of the present model, few comparison studies are carried out with the published literature. The stability and dynamic characteristics of the cracked plate are studied considering various parameters such as crack length, plate thickness, change in temperature, and internal length scale of microstructure. It has been concluded that the frequency and deflection are affected by crack length, temperature, and internal length scale of microstructure. Furthermore, to study the buckling behavior of cracked plate, the classical relations for critical buckling load and critical buckling temperature is also proposed considering the effect of crack length, temperature, and internal length scale of microstructure.

Thermal Field and Intrinsic Decoherence Effects on the Dynamics of N-level Moving Atomic System

Dynamical behaviour of Quantum Entanglement (QE) and atomic Quantum Fisher Information (AQFI) for a moving N-level atomic system is studied in a thermal environment. Time evolution of state vector of the entire system interacting with thermal field is calculated numerically in the presence of intrinsic decoherence. It is observed that intrinsic decoherence and thermal environment play dominant role during the time evolution of the quantum system. AQFI and entanglement show an opposite behaviour during its time evolution in the presence of thermal environment. AQFI is observed to be more prone to intrinsic decoherence as compared to the entanglement in a thermal environment. AQFI is found to be more prone to intrinsic decoherence as compared to the QE in a thermal environment. QE is found decaying when the parameter of intrinsic decoherence is increased in the absence of atomic motion. The damping behaviour of QE is observed for longer time-scales. The periodic response of entanglement due to atomic motion becomes moderate under the influence of these environments. The intrinsic decoherence and thermal environment are found to suppress the nonclassical effects of the quantum system. QE and AQFI saturate to a lower level for larger time-scales under the influence of these environments. Furthermore, the dynamics of AQFI and von Neumann entropy (VNE) changes remarkably by changing the mean number of photons.

Effect of Thermal Environment on Vibration Analysis of Partially Cracked Thin Isotropic Plate Submerged in Fluid

Based on a non classical plate theory, an analytical model is proposed for the first time to analyze free vibration problem of partially cracked thin isotropic submerged plate in the presence of thermal environment. The governing equation for the cracked plate is derived using the Kirchhoff’s thin plate theory and the modified couple stress theory. The crack terms are formulated using simplified line spring model whereas the effect of thermal environment is introduced using thermal moments and in-plane forces. The influence of fluidic medium is incorporated in governing equation in form fluids forces associated with inertial effects of its surrounding fluids. Applying the Galerkin’s method, the derived governing equation of motion is reformulated into well known Duffing equation. The governing equation for cracked isotropic plate has also been solved to get central deflection which shows an important phenomenon of shift in primary resonance due to crack, temperature rise and internal material length scale parameter. To demonstrate the accuracy of the present model, few comparison studies are carried out with the published literature. The variation in natural frequency of the cracked plate with uniform rise in temperature is studied considering various parameters such as crack length, fluid level and internal material length scale parameter. Furthermore the variation of the natural frequency with plate thickness is also established.

Vibration and deflection analysis of thin cracked and submerged orthotropic plate under thermal environment using strain gradient theory

Based on a non-classical plate theory, a nonlinear analytical model is proposed to analyze transverse vibration of thin partially cracked and submerged orthotropic plate in the presence of thermal environment. The governing equation for the cracked plate is derived using the Kirchhoff’s thin plate theory in conjunction with the strain gradient theory of elasticity. The effect of centrally located surface crack is deduced using appropriate crack compliance coefficients based on the simplified line spring model, whereas the effect of thermal environment is introduced using moments and in-plane forces. The influence of fluidic medium is incorporated in the governing equation in the form of fluid forces associated with its inertial effects. The equation has been solved by transforming the lateral deflection in terms of modal functions. The shift in primary resonance due to crack, length scale parameter and temperature has also been derived with central deflection. To demonstrate the accuracy of the present model, a few comparison studies are carried out with the published literature. The variation in fundamental frequency of the cracked plate is studied considering various parameters such as crack length, plate thickness, level of submergence, temperature and length scale parameter. It has been concluded that the frequency is affected by crack length, temperature and level of submergence. A comparison has also been made for the results obtained from the classical plate theory and Strain gradient theory. Furthermore, the variation in frequency response and peak amplitude of the cracked plate is studied using method of multiple scales to show the phenomenon of bending hardening or softening as affected by level of submergence, temperature, crack length and length scale parameter .

Effect of thermal environment on vibration response of partially cracked functionally graded plate coupled with fluid

Based on Kirchhoff’s classical plate theory, an analytical model is proposed for the first time to analyze the vibration response of partially cracked thin functionally graded submerged plate in presence of thermal environment. The simplified line spring model is used to formulate the crack terms whereas the effect of thermal environment is introduced using thermal moments and in-plane compressive forces. The influence of fluidic medium is incorporated in form of fluids forces associated with inertial effects of its surrounding fluids based on velocity potential function and Bernoulli’s equations. Using the Galerkin’s method, the derived governing equation of motion is reformulated into well known Duffing equation. To demonstrate the accuracy of the present model, few comparison studies are carried out with the published literature. The variation of the natural frequency of the cracked plate with uniform rise in temperature is studied considering various parameters such as length of crack, fluid level and immersed depth. It is found that the above parameters significantly affect the fundamental frequencies of cracked plate

Effect of thermal environment on free vibration and buckling of partially cracked isotropic and FGM micro plates based on a non classical Kirchhoff's plate theory: An analytical approach

A non classical analytical model is presented for free vibration of the cracked rectangular isotropic and functionally graded micro plates in the presence of thermal environment. The new approach is based on the combination of classical plate theory and the modified couple stress theory. The crack terms are based on the Line Spring Model whereas the thermal environment is accommodated in the form of thermal moment and in-plane forces. The solution for fundamental frequencies of the cracked plate is obtained by discounting geometric nonlinearity. A non classical relation for geometrically linear thermal buckling phenomenon of a cracked micro-plate is also proposed. The variation of critical buckling temperature and fundamental frequency with uniform rise in temperature of the cracked plate is studied for various crack length ratios, gradient index and internal material length scale parameter. Furthermore the variation of the buckling coefficient with plate aspect ratio and thickness of the cracked micro-plate is established. A comparison is presented between the classical results and present results as affected by thermal environment and microstructure of the plate. It is concluded that the presence of cracks affects the critical buckling temperature and fundamental frequencies of micro plates. The consideration of size effect increases the buckling temperature which shows the significance of the internal material length scale parameter in the presence of thermal environment.

Distinguishing quantum states using time-traveling qubits in the presence of thermal environments

We consider quantum circuits with time travel designed for distinguishing specific nonorthogonal quantum states in two most popular models: Deutschs and postselected. We modify them by a presence of weakly coupled thermal environment. Using the Davies approximation we study how the thermal noise affects an ability of the circuits to distinguish nonorthogonal quantum states. We show that for purely dephasing environment a paradoxial power of such circuits remains preserved. We also present a physics based argument for conditions of validity of the maximum entropy rule introduced by David Deutsch for resolving the uniqueness ambiguity in a circuit with time travel.

Vibration and buckling analysis of partially cracked thin orthotropic rectangular plates in thermal environment

An analytical model is presented for vibration of a thin orthotropic plate containing two perpendicular continuous line surface cracks located at the centre of the plate in the presence of thermal environment. Also new configuration of two perpendicular cracks as internal cracks, located along the thickness of the plate is studied by considering appropriate crack compliance coefficients based on line-spring model. Equilibrium principle based on Classical Plate Theory is used to derive the equations of motion for cracked plate, wherein the crack terms are formulated using the line spring model. The moments due to thermal environment are neglected in the results and only uniform heating of the cracked plate is considered. The solution for natural frequencies of cracked plate is obtained by Galerkin’s method. A relation for thermal buckling phenomenon for the cracked plate is also formulated. The influence of the lengths of the two cracks and their location along the thickness of the plate on critical buckling temperature and first mode natural frequency is demonstrated. The geometrically linear frequency response relation for cracked plate is formulated using the method of multiple scales. It is thus concluded that the presence of the two cracks affect the critical buckling temperature and natural frequencies.

An efficient shear deformation theory for wave propagation of functionally graded material plates

An efficient shear deformation theory is developed for wave propagation analysis of an infinite functionally graded plate in the presence of thermal environments. By dividing the transverse displacement into bending and shear parts, the number of unknowns and governing equations of the present theory is reduced, and hence, makes it simple to use. The thermal effects and temperature-dependent material properties are both taken into account. The temperature field is assumed to be a uniform distribution over the plate surface and varied in the thickness direction only. Material properties are assumed to be temperature-dependent, and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. The governing equations of the wave propagation in the functionally graded plate are derived by employing the Hamilton's principle and the physical neutral surface concept. There is no stretching.bending coupling effect in the neutral surface-based formulation, and consequently, the governing equations and boundary conditions of functionally graded plates based on neutral surface have the simple forms as those of isotropic plates. The analytic dispersion relation of the functionally graded plate is obtained by solving an eigenvalue problem. The effects of the volume fraction distributions and temperature on wave propagation of functionally graded plate are discussed in detail. It can be concluded that the present theory is not only accurate but also simple in predicting the wave propagation characteristics in the functionally graded plate. The results carried out can be used in the ultrasonic inspection techniques and structural health monitoring.

Roles of thermal noise and detector efficiency in distillation of continuous variable entanglement state

We address the degradation of continuous variable (CV) entanglement distillation in the presence of thermal environment and nonunity detecting efficiency. We explore the logarithmic negativity as a criteria and compare the output entanglement between the schemes of single-photon subtraction (PS) and two-PS. The probability of success is also investigated. We show that compared with detector efficiency, thermal noise plays a more dominant role in Gaussian entanglement distillation. Our results shed more light on the noise mechanism that influences realistic CV entanglement distillation and is of experimental relevance in developing a more efficient entanglement distillation scheme.