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Showing papers on "Thermoelastic damping published in 2004"


Journal ArticleDOI
TL;DR: In this paper, a derivation of the governing equations for generalized thermodiffusion in elastic solids is given, and the uniqueness of solution of these equations under suitable conditions is proved.

379 citations


Journal ArticleDOI
TL;DR: In this article, the fatigue of dual phase steel was examined in terms of calorimetric effects in order to match the energy manifestations of fatigue and constitutive equations drawn up in a thermomechanical framework.

267 citations


Journal ArticleDOI
TL;DR: In this article, the authors present a model and analytical expressions for the quality factors of microplates of general shapes and boundary conditions due to thermoelastic damping, which decouple the thermal equation from the plate equation.
Abstract: We present a model and analytical expressions for the quality factors of microplates of general shapes and boundary conditions due to thermoelastic damping. We solve the heat equation for the thermal flow across the microplate, and hence decouple the thermal equation from the plate equation. We utilize a perturbation method to derive an analytical expression for the quality factor of a microplate under electrostatic loading and residual stresses in terms of its structural mode shapes. For the special case of no electrostatic and in-plane loadings, we derive a simple analytical expression for the quality factor, which is independent of the mode shapes. We verify the model by specializing it to a microbeam and comparing the resulting quality factor to that obtained using microbeam models in the literature. We present several results for various modes of rectangular microplates with various boundary conditions.

193 citations


Book
01 Jan 2004
TL;DR: In this article, the authors present a generalized theory of Micropolar Thermelasticity, which is based on the linear theory of nonlinear properties of thermodynamic properties of materials with voids.
Abstract: Introduction. 1: Thermoelastic Materials with Voids. 1.1. Preliminaries. The Laws of Thermodynamics. 1.2. Constitutive Equations. Thermodynamic Restrictions. 1.3. Boundary-Initial-Value Problems. 1.4. Continuous Data Dependence and Uniqueness Results. 1.5. The Linear Theory. 2: Dynamic Theory. 2.1. Uniqueness Results. 2.2. Reciprocal Theorem. Applications. 2.3. Homogeneous and Isotropic Bodies. 2.4. Acceleration Waves. 2.5. Harmonic Waves. 2.6. Concentrated Loads. 2.7. Radiation Conditions. 2.8. Potentials. 3: Equilibrium Theory. 3.1. Thermoelastic States. 3.2. The Thermoelastic Plane Strain. 3.3. Exercises. 4: Prestressed Thermoelastic Bodies. 4.1. Equations of Perturbed Motion. 4.2. An Existence Result. 5: Thermoelastic Cosserat Continua. 5.1. The Linear Theory of Micropolar Thermoelasticity. 5.2. Thermoelastic Processes. Boundary-Initial-Value Problem. 5.3. Reciprocity. Existence and Uniqueness Results. 5.4. Variational Theorem. 5.5. Homogeneous and Isotropic Solids. Plane Waves. 5.6. A Representation of Galerkin Type. Fundamental Solutions. 5.7. Transient Waves. 5.8. Plane Strain Problem. 5.9. Bending of Micropolar Thermoelastic Plates. 5.10. A Generalized Theory of Micropolar Thermoelasticity. 6: Thermoelastostatics of Micropolar Bodies. 6.1. Boundary Value Problems. Basic Theorems. 6.2. Special Results for Homogeneous and Isotropic Bodies. 6.3. The Equilibrium Plane Problems. 6.4. Exercises. 6.5. Thermal Stresses in Beams. 6.6. Cylinders Composed of Different Materials. 7: Nonsimple Materials. 7.1. The Nonlinear Thermoelasticity. 7.2. Uniqueness and Continuous Dependence results. 7.3. Linear Theories. 7.4. Isotropic Bodies. 7.5. A Grade Consistent Theory of Micropolar Thermoelasticity. References. Index.

191 citations


Journal ArticleDOI
Jacob Aboudi1
TL;DR: In this article, the generalized method of cells and the recently developed high-fidelity generalized method for cells are reviewed and both infinitesimal and finite deformation analyses of multiphase composites are discussed.
Abstract: The models of the generalized method of cells and the recently developed high-fidelity generalized method of cells are reviewed. These two methods are micromechanical theories that are capable of providing the overall behavior of periodic multiphase materials of various types, including thermoelastic, viscoelastic, thermo-inelastic, and electromagnetothermoelastic materials. Both infinitesimal and finite deformation analyses of multiphase composites are discussed.

158 citations


Journal ArticleDOI
Jihoon Choi1, In Lee1
01 Jul 2004-Wear
TL;DR: In this article, a transient analysis for the contact problem of disk brakes with frictional heat generation is performed using the finite element method, where the coupled heat conduction and elastic equations are solved with contact problems, and the numerical simulation for the thermoelastic behavior of disk brake is obtained in the repeated brake condition.

158 citations


Journal ArticleDOI
TL;DR: Using an optical technique, picosecond shear and quasishear coherent acoustic phonon pulses in the time domain are generated and detected and efficient detection in isotropic and anisotropic media with various optical incidence geometries is demonstrated.
Abstract: Using an optical technique we generate and detect picosecond shear and quasishear coherent acoustic phonon pulses in the time domain. Thermoelastic and piezoelectric generation are directly achieved by breaking the sample lateral symmetry using crystalline anisotropy. We demonstrate efficient detection in isotropic and anisotropic media with various optical incidence geometries.

144 citations


Journal ArticleDOI
TL;DR: In this paper, the authors studied the transient thermoelastic deformations of a thick functionally graded plate with edges held at a uniform temperature and either simply supported or clamped.
Abstract: We study transient thermoelastic deformations of a thick functionally graded plate with edges held at a uniform temperature and either simply supported or clamped. Either the temperature or the heat flux is prescribed on the top surface of the plate with the bottom surface of the plate kept at either a uniform temperature or thermally insulated. Stresses and deformations induced due to the simultaneous application of the transient thermal and mechanical loads are also computed. The problem is solved by using a higher order shear and normal deformable plate theory and a meshless local Petrov–Galerkin method. Only nodal coordinates are needed, and neither nodal connectivity nor a background mesh is employed. The validity of the method and of the computer code is established by comparing computed results with the analytical solution of the three-dimensional thermoelasticity equations for a simply supported plate. Results are then computed for clamped plates. It is found that the centroidal deflection and the...

136 citations


Journal ArticleDOI
TL;DR: In this article, the results of fatigue crack growth tests performed on welded ferritic steel plates are reported, and it can be observed that the technique is sensitive to the effects of crack closure and the presence of tensile and compressive residual stresses due to welding.
Abstract: Thermoelastic stress analysis has been developed in recent years as a direct method of investigating the crack tip stresses in a structure under cyclic loading. This is a consequence of the fact that stress intensity factors obtained from thermoelastic experiments are determined from the cyclic stress field ahead of a fatigue crack, rather than inferred from measurement of the crack length and load range. In the present paper the results of fatigue crack growth tests performed on welded ferritic steel plates are reported. From the results it can be observed that the technique is sensitive to the effects of crack closure and the presence of tensile and compressive residual stresses due to welding.

135 citations


Journal ArticleDOI
TL;DR: In this paper, physical models and numerical simulations are applied to describe the thermal-dynamical processes of the high current pulsed electron beam (HCPEB) treatment, which reveals an ultrahigh heating/cooling rate in the order of 10 8 -10 9 K/s, as well as rapid melting and re-solidification within microseconds in time and micrometers in depth.
Abstract: Physical models and numerical simulations are applied to describe the thermal–dynamical processes of the high current pulsed electron beam (HCPEB) treatment. The simulation of the temperature distributions reveals an ultrahigh heating/cooling rate in the order of 10 8 –10 9 K/s, as well as rapid melting and re-solidification within microseconds in time and micrometers in depth. It is also pointed out that the melting starts at a sublayer about 1–2 μm in depth, which constitutes the crater formation mechanism. A temperature-induced dynamic thermal stress fields can then generate three principal stress, the quasi-static stress, the thermoelastic stress and the shock stress, the latter two being stress waves. The thermoelastic stress wave has small amplitudes less than 0.1 MPa. The shock stress wave however is a typical nonlinear wave, several hundreds of MPa in amplitudes, much stronger than the thermoelastic stress wave, and has a strong impact on materials structure and properties far beyond the heat-affected zone. The maximum compressive quasi-static stress in the surface layer reaches several hundreds of MPa, which easily induces surface deformation in metallic materials.

121 citations


Journal ArticleDOI
TL;DR: In this paper, thermal buckling and post-buckling analyses for moderately thick laminated rectangular plates that contain functionally graded materials (FGMs) and subjected to a uniform temperature change are presented.
Abstract: This paper presents thermal buckling and post-buckling analyses for moderately thick laminated rectangular plates that contain functionally graded materials (FGMs) and subjected to a uniform temperature change. The theoretical formulation employs the first-order shear deformation theory and accounts for the effect of temperature-dependent thermoelastic properties of the constituent materials and initial geometric imperfection. The principle of minimum total potential energy, the differential quadrature method, and iterative algorithms are used to obtain critical buckling temperatures and the post-buckling temperature-deflection curves. The results are presented for both symmetrically and unsymmetrically laminated plates with ceramic/metal functionally graded layers, showing the effects of temperature-dependent properties, layup scheme, material composition, initial imperfection, geometric parameters, and boundary conditions on buckling temperature and thermal post-buckling behavior.

Journal ArticleDOI
TL;DR: In this paper, the authors used the 3D discrete element method (DEM) for computer simulation and characterization of particle damping, which is a technique of providing damping with granular particles embedded within small holes in a vibrating structure.
Abstract: Particle damping is a technique of providing damping with granular particles embedded within small holes in a vibrating structure. The particles absorb kinetic energy through particle-to-wall and particle-to-particle frictional collisions. While the concept of particle damping seems to be simple and it has been used successfully in many fields for vibration reduction, it is difficult to predict the damping characteristics due to complex collisions in the dense particle flow. In this paper, we utilize the 3D discrete element method (DEM) for computer simulation and characterization of particle damping. With the DEM modeling tool validated with experimental results, it is shown that the particle damping can achieve a very high value of specific damping capacity. Furthermore, simulations provide information of particle motions within the container hole during three different regions and help explain their associated damping characteristics. The particle damping is a combination of the impact and the friction damping. The damping is found to be highly nonlinear as the rate of energy dissipation depends on amplitude. Particularly, the damping effect results in a linear decay in amplitude over a finite period of time. These characteristics are examined with respect to a simple single-mass impact damper and a dry-friction damper. It is concluded that the particle damping is a mix of these two damping mechanisms. It is further shown that the relative significance of these damping mechanisms depends on a particular arrangement of the damper. This study represents an effort towards a deeper understanding of particle damping to provide a comprehensive methodology for its analysis and design.

Journal ArticleDOI
TL;DR: In this article, the authors analyzed one fundamental source of dissipation in thin coatings, thermoelastic damping associated with the dissimilar thermal and elastic properties of the film and the substrate.
Abstract: The displacement noise in the test-mass mirrors of interferometric gravitational wave detectors is proportional to their elastic dissipation at the observation frequencies. In this paper, we analyze one fundamental source of dissipation in thin coatings, thermoelastic damping associated with the dissimilar thermal and elastic properties of the film and the substrate. We obtain expressions for the thermoelastic dissipation factor necessary to interpret resonant loss measurements, and for the spectral density of displacement noise imposed on a Gaussian beam reflected from the face of a coated mass. The predicted size of these effects is large enough to affect the interpretation of loss measurements, and to influence design choices in advanced gravitational wave detectors.

Journal ArticleDOI
TL;DR: In this paper, the results obtained from the finite element model of laser-generated ultrasound are presented in terms of temperature and displacement, and the numerical results demonstrate that the surface vibration is mainly determined by the lower frequency components of the symmetric mode s0 and antisymmetric mode a0 of the lowest order in very thin plate materials.
Abstract: The results obtained from the finite element model of laser-generated ultrasound are presented in terms of temperature and displacement. According to thermoelastic theory, considering the temperature dependence of the thermophysical parameters of the material, the transient temperature field can be precisely calculated by using the finite element method; then, laser-generated surface acoustic wave forms are calculated in Al plates of various thicknesses. The elastic waves excited by a pulsed laser in a thin plate are typical Lamb waves, and the numerical results demonstrate that the surface vibration is mainly determined by the lower frequency components of the symmetric mode s0 and antisymmetric mode a0 of the lowest order in very thin plate materials. It is also indicated that, when the sample thickness increases, both the higher frequency components of the lower Lamb wave modes and the higher order Lamb wave modes should be considered. In a relatively thicker plate, the numerical model can still captur...

Journal ArticleDOI
TL;DR: In this paper, the superelastic effect under constant magnetic fields exhibited by the Ni-Mn-Ga ferromagnetic thermoelastic martensites with single-variant and polyvariant microstructure is studied experimentally and theoretically.
Abstract: The superelastic effect under constant magnetic fields exhibited by the Ni-Mn-Ga ferromagnetic thermoelastic martensites with single-variant and polyvariant microstructure is studied experimentally and theoretically. The formerly proposed statistical model of the magnetostrain effect in the ferromagnetic martensite is modified for the theoretical description of the superelastic stress-strain dependence under magnetic field. The mechanical stress, which is equivalent to the internal stress induced by the magnetic field, is determined by fitting the theoretical stress-strain curves to the experimental results. A quadratic dependence of the field-induced stress on the value of the magnetization of martensite is found. This dependence supports the model assumption that a magnetoelastic interaction causes the magnetostrain effect.

Journal ArticleDOI
TL;DR: In this article, the theoretical treatment of transient thermoelastic problem involving a functionally graded thick strip due to non-uniform heat supply in the width direction was studied. But the authors focused on the thermal and thermo-elastic constants of the strip are assumed to vary exponentially in the thickness direction.

Journal ArticleDOI
TL;DR: In this paper, a combined finite difference/finite element algorithm is developed for solving the coupled, nonlinear, transient differential equations, and it is shown that the thermomechanical results obtained from the ultrafast thermoelasticity are significantly different from those obtained from Lord-Shulman theory and the classical thermodynamic model.

Journal ArticleDOI
TL;DR: In this article, the authors consider several methods to achieve high values of this figure of merit: high damping metals, metal matrix composites, and composites containing constituents of negative stiffness.
Abstract: The figure of merit for structural damping and damping layer applications is the product of stiffness E and damping tan δ. For most materials, even practical polymer damping layers, E tan δ is less than 0.6 GPa. We consider several methods to achieve high values of this figure of merit: high damping metals, metal matrix composites and composites containing constituents of negative stiffness. As for high damping metals, damping of polycrystalline zinc was determined and compared with InSn studied earlier. Damping of Zn is less dependent on frequency than that of InSn, so Zn is superior at high frequency. High damping and large stiffness anomalies are possible in viscoelastic composites with inclusions of negative stiffness. Negative stiffness entails a reversal of the usual directional relationship between force and displacement in deformed objects. An isolated object with negative stiffness is unstable, but an inclusion embedded in a composite matrix can be stabilized under some circumstances. Ferroelastic domains in the vicinity of a phase transition can exhibit a region of negative stiffness. Metal matrix composites containing vanadium dioxide were prepared and studied. The concentration of embedded particles was sensitive to the processing method.

Journal ArticleDOI
TL;DR: In this article, the effect of carbon nanotubes on the overall effective thermoelastic properties of reinforced polymers (NRP) were estimated numerically by using a finite element based procedure.
Abstract: The overall effective thermoelastic properties of nanotube reinforced polymers (NRP) were estimated numerically by using a finite element based procedure. Three-dimensional multi-inclusion periodic computer models were built for three different nanotube orientation states, namely, fully aligned, two-dimensional random in-plane and three-dimensional random states. The enhancement of the Young's modulus as well as the decrease of the thermal expansion coefficient were calculated numerically, assuming technologically relevant combinations of the nanotube aspect ratio and volume fraction. Maximal changes of the thermoelastic properties can be achieved in the longitudinal direction of NRPs with fully aligned carbon nanotubes whereas two-dimensional random in-plane and three-dimensional random composite morphologies exhibit more moderate enhancements but in more than one direction. Numerical predictions for the enhancements of the thermoelastic properties confirmed that carbon nanotubes can be considerably more effective for the reinforcement of polymers than conventional glass or carbon fibres.

Journal ArticleDOI
TL;DR: In this article, a model for the scanning laser source (SLS) technique is presented, based on the decomposition of the field generated by the laser in a cracked 2D half-space, by virtue of linear superposition, into the incident and the scattered fields.

Journal ArticleDOI
TL;DR: In this article, the three-dimensional steady-state basic equations of thermoelasticity for a transversely isotropic elastic medium are simplified by introducing two displacement functions.

Journal ArticleDOI
TL;DR: In this article, the authors developed accurate and time efficient numerical approaches to study geometrically nonlinear vibrations of moderately thick beams under the combined action of mechanical and thermal loads.

Journal ArticleDOI
TL;DR: In this paper, a one-dimensional generalized thermoelasticity model of a disk based on the Lord-Shulman theory is presented, where the effects of the relaxation time and coupling coefficient are studied.
Abstract: A one-dimensional generalized thermoelasticity model of a disk based on the Lord–Shulman theory is presented. The dynamic thermoelastic response of the disk under axisymmetric thermal shock loading is studied. The effects of the relaxation time and coupling coefficient are studied. The Laplace transform method is used to transform the coupled governing equations into the space domain, where the Galerkin finite element method is employed to solve the resulting equations in the transformed domain. The dimensionless temperature, displacement, and stresses in the transformed domain are inverted to obtain the actual physical quantities using the numerical inversion of the Laplace transform method.

Journal ArticleDOI
TL;DR: In this article, the authors measured the mechanical dissipation of a number of types of coatings formed from SiO2 (silica) and Ta2O5 (tantala) and determined the frequency dependence of the dissipation, taking into account the contribution of thermoelastic loss.
Abstract: All current gravitational wave detectors use test masses coated with alternating layers of two different dielectric materials to form highly reflective mirrors. The thermal noise from mechanical dissipation associated with such coatings may be significant for future detectors such as advanced LIGO. We have measured the mechanical dissipation of a number of types of coatings formed from SiO2 (silica) and Ta2O5 (tantala). The frequency dependence of the dissipation has been determined, taking into account the contribution of thermoelastic loss.

Journal ArticleDOI
TL;DR: A radiative thermal corrector that can counteract thermal lensing and (or) thermoelastic deformation induced by coating and substrate absorption of collimated Gaussian beams is described.
Abstract: Absorption of laser beam power in optical elements induces thermal gradients that may cause unwanted phase aberrations. In precision measurement applications, such as laser interferometric gravitational-wave detection, corrective measures that require mechanical contact with or attachments to the optics are precluded by noise considerations. We describe a radiative thermal corrector that can counteract thermal lensing and (or) thermoelastic deformation induced by coating and substrate absorption of collimated Gaussian beams. This radiative system can correct anticipated distortions to a high accuracy, at the cost of an increase in the average temperature of the optic. A quantitative analysis and parameter optimization is supported by results from a simplified proof-of-principle experiment, demonstrating the method’s feasibility for our intended application.

Journal ArticleDOI
TL;DR: In this paper, the authors derived equilibrium and stability equations under thermal and mechanical loads based on first-order shear deformation plate theory, assuming that the material properties vary as a power form of the thickness coordinate variable and using the variational method.
Abstract: Axisymmetric thermal and mechanical buckling of functionally graded circular plates is considered. Equilibrium and stability equations under thermal and mechanical loads are derived based on first-order shear deformation plate theory. Assuming that the material properties vary as a power form of the thickness coordinate variable z and using the variational method, the system of fundamental ordinary differential equations is established. Buckling analysis of a functionally graded plate under uniform temperature rise, linear and nonlinear gradient through the thickness, and uniform radial compression are considered, and the critical buckling loads are derived for clamped edge plates. The results are compared with the buckling loads obtained for a functionally graded plate based on the classical plate theory given in the literature.

Journal ArticleDOI
TL;DR: In this article, the residual thermoelastic stresses in Al2O3-ZrO2 (monoclinic zirconia, m-ZRO2) and Al 2O3 -Zr O2 (tetragonal zirconsia, t-Zrin O2) fibrous eutectics were studied using different piezospectrosocopic probes.
Abstract: The residual thermoelastic stresses were studied in Al2O3–ZrO2 (monoclinic zirconia, m-ZrO2) and Al2O3–ZrO2(Y2O3) (tetragonal zirconia, t-ZrO2) fibrous eutectics that were produced via the laser floating zone method, using different piezospectrosocopic probes. The luminescence of the R-lines of ruby (Cr3+ in Al2O3 phase) was used to determine the stresses in the Al2O3 matrix, assuming that the stress state in the fibers was transversally isotropic. The sapphire matrix was subjected to tensile stresses in the Al2O3–m-ZrO2 eutectics. The hydrostatic stress component attained a value of 1.13 GPa in well-ordered regions. In contrast, sapphire was in compression in the Al2O3–ZrO2(Y2O3) fibers, and the hydrostatic stress was −0.37 GPa in both ordered and disordered regions. The influence of the microstructure in the residual stresses was explained through thermoelastic analyses, based on a self-consistent method. In addition, the Raman spectra of m-ZrO2 and the 417 cm−1 Raman mode of Al2O3 were measured in samples that showed different microstructures and thermoelastic stresses. An approximate linear dependence was observed in the tension–compression range between frequency shifts of the Al2O3R-lines and those of the 417 cm−1 Raman mode.

Journal ArticleDOI
TL;DR: In this paper, the propagation of plane waves in infinite, three-dimensional, type-III thermoelastic media is investigated and exact dispersion relation solutions are determined and several characterizations of the wavefield are examined.
Abstract: The propagation of plane waves in infinite, three–dimensional, type–III thermoelastic media is investigated. Exact dispersion relation solutions are determined and several characterizations of the wavefield are examined. Low– and high–frequency asymptotic expressions are given, small–coupling limit results are derived, and special/limiting cases, including those corresponding to thermoelastic media of types II and I, are noted. Computational tools are used to illustrate the analytical findings and to study the effects of varying the physical parameters. Of the findings presented, the following are most significant: (i) the determination of critical values of the physical parameters and their impact on the wavefields; (ii) ascertaining that type–III media behave, essentially, like type–II (respectively, type–I) media with respect to low– (respectively, high–) frequency plane waves; (iii) establishing the Whitham stability of plane waves in type–III media; and (iv) the determination of the dispersion characteristics of type–III media.

Journal ArticleDOI
TL;DR: In this article, Tungsten carbide particles are embedded within longitudinal (and latitudinal) holes drilled in the structure, as a simple and passive means for vibration suppression, and the experimental results confirm a numerical prediction that shear friction in the longitudinal and the latitudinal directions is effective as the major contributing mechanism of damping in the case.
Abstract: This paper describes an experimental investigation of a particle damping method for a beam and a plate. Tungsten carbide particles are embedded within longitudinal (and latitudinal) holes drilled in the structure, as a simple and passive means for vibration suppression. Unlike in traditional damping materials, mechanisms of energy dissipation of particle damping are highly nonlinear and primarily related to friction and impact phenomena. Experiments are conducted with a number of arrangements of the packed particles including different particle sizes and volumetric packing ratios. The results show that the particle damping is remarkably effective and that strong attenuations are achieved within a broad frequency range. The effects of the system parameters including particle size, packing ratio and particle material are studied by broadband and narrowband random excitations. The experimental results confirm a numerical prediction that shear friction in the longitudinal (and the latitudinal) directions is effective as the major contributing mechanism of damping in the case. Another unique feature of linear decay in free vibrations is also observed in this case of particle damping.