Showing papers on "Thermoelastic damping published in 1988"
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TL;DR: Otsuka et al. as mentioned in this paper showed a one-to-one correspondence between shape memory effect and the thermoelastic martensitic transformation in a Cu-AI-Ni alloy.
Abstract: In some alloys, a given plastic strain recovers completely when the con cerned alloy is heated above a certain temperature. This phenomenon, shape memory effect (SME), was observed in Au-Cd (1) and In-Tl (2) alloys in the first half of 1950s. However, SME was not a focus of research until it was found in a Ti-Ni alloy (3) in 1963, when the phenomenon was first termed the shape memory effect. A similar phenomenon was found in a Cu-AI-Ni alloy as well (3a). At that time, however, SME was considered to be a peculiar phenomenon limited to the specific Ti-Ni alloy. In 1970, Otsuka & Shimizu (4, 4a) unambiguously demonstrated a one to-one correspondence between SME and the thermoelastic martensitic transformation in a Cu-AI-Ni alloy. Thus, they concluded that SME is characteristic of alloys exhibiting thermoelastic martensitic trans formations. They ascribed the origin to the crystallographic reversibility of the thermoelastic transformation and the presence of a recoverable deformation mode, i.e. twinning, in thermoelastic alloys. Since then, there
1,497 citations
TL;DR: In this article, the thermodynamics of thermoelastic martensitic transformations are reformulated from the point of view of calorimetric experiments, and it is shown that the heat released or absorbed by the specimen is due to a triple contribution: the latent heat of transformation, the reversibly stored elastic enthalpy and the irreversible work mainly spent in moving the interfaces.
295 citations
TL;DR: In this article, the residual stresses in APC-2 cross-ply laminates have been investigated and predictions based on classical laminate theory are compared to measured levels of residual stress obtained from a number of experimen tal techniques.
Abstract: Residual stresses in composite laminates depend on thermoelastic properties of the material and processing temperatures. Their distribution in the various laminae is a func tion of stacking sequence and ply orientation. In this work residual stresses in APC-2 cross-ply laminates have been investigated. Predictions based on classical laminate theory are compared to measured levels of residual stress obtained from a number of experimen tal techniques. The analysis of the results shows that accurate predictions can be made pro vided that the changes in thermoelastic properties of the materials with temperature are taken into account.
212 citations
TL;DR: In this article, a model is developed to approximate the elastic response of a composite body reinforced by coated, fibers oriented in various directions, and a parametric study has been conducted to illustrate how a coating applied to the fiber influences the effective thermoelastic properties and can alter the state of stress at the fiber-matrix interface and thereby modify or control an observed mode of failure.
150 citations
TL;DR: In this paper, a synthesis of various theoretical models representing the acoustic displacements generated by a point laser impact is given, and then validated by interferometer measurements of ultrasonic displacement generated both under ablation conditions and under thermoelastic conditions.
116 citations
TL;DR: In this article, a revised theory of the thermoelastic effect was presented which offers an explanation of the mean stress dependence of the thermodynamic constant, and further experimental results were presented to validate this theory, and to demonstrate that the predicted higher harmonic thermal response of a body under a single frequency excitation is indeed observable.
103 citations
TL;DR: The application of the SPATE technique to two different composite material specimens is described and the results are critically discussed in this article, where the relevant theory which permits a quantitative interpretation of the thermoelastic response from orthotropic materials is outlined.
Abstract: The application of the thermoelastic technique (SPATE) to two different composite material specimens is described and the results are critically discussed. The relevant theory, which permits a quantitative interpretation of the thermoelastic response from orthotropic materials, is outlined.
94 citations
TL;DR: In this paper, a system known as SPATE (stress pattern analysis by measurement of thermal emission) has been developed which can detect changes in infrared emission due to minute changes in the temperature of a dynamically stressed material.
Abstract: The term thermoelastic effect refers to the coupling between mechanical deformation and the change in thermal energy of an elastic material. The first theoretical treatment of this phenomenon is attributed to Lord Kelvin1, and the resulting law states that the rate of change in temperature of a dynamically loaded body is directly related to the rate of change of the principal stress sum under adiabatic conditions. Although Kelvin's law has been well known for over a century, it is only in the past ten years that the thermoelastic effect has been exploited as a means for dynamic stress analysis. A system known as SPATE (stress pattern analysis by measurement of thermal emission) has been developed which can detect changes in infrared emission due to minute changes in the temperature of a dynamically stressed material. Recently it was discovered that the SPATE response or, more generally, the thermal response of a cyclically loaded body is not only a function of the dynamic part of the stress, but also of the static component2. This finding has led to the suggestion that residual stresses within a material might be detected using this phenomenon, and here we present the first demonstration of such a means of residual stress measurement.
71 citations
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31 Dec 1988TL;DR: In this paper, the authors derived the governing equation for a plate with moment-curvature relations and integrated stress resultant-displacement relations and derived the equilibrium equation for the plate.
Abstract: 1. Equations of Linear Elasticity in Cartesian Coordinates.- 1.1 Stresses.- 1.2 Displacements.- 1.3 Strains.- 1.4 Isotropy and Its Elastic Constants.- 1.5 Equilibrium Equations.- 1.6 Stress-Strain Relations.- 1.7 Linear Strain-Displacement Relations.- 1.8 Compatibility Equations.- 1.9 Summary.- 1.10 References.- 1.11 Problems.- 2. Derivation of the Governing Equations for Beams and Rectangular Plates.- 2.1 Assumptions of Plate Theory.- 2.2 Derivation of the Equilibrium Equations for a Plate.- 2.3 Derivation of Plate Moment-Curvature Relations and Integrated Stress Resultant- Displacement Relations.- 2.4 Derivation of the Governing Equations for a Plate.- 2.5 Boundary Conditions.- 2.6 Stress Distribution within a Plate.- 2.7 References.- 2.8 Problems.- 3. Beams and Rods.- 3.1 General Remarks.- 3.2 Development of the Governing Equations.- 3.3 Solutions for the Beam Equation.- 3.4 Stresses in Beams - Rods - Columns.- 3.5 Example: Clamped-Clamped Beam with a Constant Lateral Load, q(x) = -q0.- 3.6 Example: Cantilevered Beam with a Uniform Lateral Load, q(x) = -q0.- 3.7 Example: Simply Supported Beam with a Uniform Load over Part of Its Length.- 3.8 Beam with an Abrupt Change in Stiffness.- 3.9 Beam Subjected to Concentrated Loads.- 3.10 Solutions by Green's Functions.- 3.11 Tapered Beam Solution Using Galerkin's Method.- 3.12 Problems.- 4. Solutions to Problems of Rectangular Plates.- 4.1 Some General Solutions to the Biharmonic Equation.- 4.2 Double Series Solution (Navier Solution).- 4.3 Single Series Solution (Method of M. Levy).- 4.4 Example of Plate with Edges Supported by Beams.- 4.5 Summary.- 4.6 References.- 4.7 Problems.- 5. Thermal Stresses in Plates.- 5.1 General Considerations.- 5.2 Derivation of the Governing Equations for a Thermoelastic Plate.- 5.3 Boundary Conditions.- 5.4 General Treatment of Plate Nonhomogeneous Boundary Conditions.- 5.5 Thermoelastic Effects on Beams.- 5.6 Self-Equilibration of Thermal Stresses.- 5.7 References.- 5.8 Problems.- 6. Circular Plates.- 6.1 Introduction.- 6.2 Derivation of the Governing Equations.- 6.3 Axially Symmetric Circular Plates.- 6.4 Solutions for Axially Symmetric Circular Plates.- 6.5 Circular Plate, Simply Supported at the Outer Edge, Subjected to a Uniform Lateral Loading, p0.- 6.6 Circular Plate, Clamped at the Outer Edge, Subjected to a Uniform Lateral Loading, p0.- 6.7 Annular Plate, Simply Supported at the Outer Edge, Subjected to a Stress Couple, M, at the Inner Boundary.- 6.8 Annular Plate, Simply Supported at the Outer Edge, Subjected to a Shear Resultant, Q0, at the Inner Boundary.- 6.9 General Remarks.- 6.10 Problems.- 7. Buckling of Columns and Plates.- 7.1 Derivation of the Plate Governing Equations for Buckling.- 7.2 Buckling of Columns Simply Supported at Each End.- 7.3 Column Buckling with Other Boundary Conditions.- 7.4 Buckling of Plates Simply Supported on All Four Edges.- 7.5 Buckling of Plates with Other Loads and Boundary Conditions.- 7.6 References.- 7.7 Problems.- 8. The Vibrations of Beams and Plates.- 8.1 Introduction.- 8.2 Natural Vibrations of Beams.- 8.3 Natural Vibrations of Plates.- 8.4 Forced Vibrations of Beams and Plates.- 8.5 References.- 8.6 Problems.- 9. Energy Methods in Beams, Columns and Plates.- 9.1 Introduction.- 9.2 Theorem of Minimum Potential Energy.- 9.3 Analysis of Beams Subjected to a Lateral Load.- 9.4 The Buckling of Columns.- 9.5 Vibration of Beams.- 9.6 Minimum Potential Energy for Rectangular Plates.- 9.7 The Buckling of a Plate under Uniaxial Load, Simply Supported on Three Sides, and Free on an Unloaded Edge.- 9.8 Functions to Assume in the Use of Minimum Potential Energy for Solving Beam, Column, and Plate Problems.- 9.9 Problems.- 10. Cylindrical Shells.- 10.1 Cylindrical Shells under General Loads.- 10.2 Circular Cylindrical Shells under Axially Symmetric Loads.- 10.3 Edge Load Solutions.- 10.4 A General Solution for Cylindrical Shells under Axially Symmetric Loads.- 10.5 Sample Solutions.- 10.6 Circular Cylindrical Shells under Asymmetric Loads.- 10.7 Shallow Shell Theory (Donnell'1. Equations of Linear Elasticity in Cartesian Coordinates.- 1.1 Stresses.- 1.2 Displacements.- 1.3 Strains.- 1.4 Isotropy and Its Elastic Constants.- 1.5 Equilibrium Equations.- 1.6 Stress-Strain Relations.- 1.7 Linear Strain-Displacement Relations.- 1.8 Compatibility Equations.- 1.9 Summary.- 1.10 References.- 1.11 Problems.- 2. Derivation of the Governing Equations for Beams and Rectangular Plates.- 2.1 Assumptions of Plate Theory.- 2.2 Derivation of the Equilibrium Equations for a Plate.- 2.3 Derivation of Plate Moment-Curvature Relations and Integrated Stress Resultant- Displacement Relations.- 2.4 Derivation of the Governing Equations for a Plate.- 2.5 Boundary Conditions.- 2.6 Stress Distribution within a Plate.- 2.7 References.- 2.8 Problems.- 3. Beams and Rods.- 3.1 General Remarks.- 3.2 Development of the Governing Equations.- 3.3 Solutions for the Beam Equation.- 3.4 Stresses in Beams - Rods - Columns.- 3.5 Example: Clamped-Clamped Beam with a Constant Lateral Load, q(x) = -q0.- 3.6 Example: Cantilevered Beam with a Uniform Lateral Load, q(x) = -q0.- 3.7 Example: Simply Supported Beam with a Uniform Load over Part of Its Length.- 3.8 Beam with an Abrupt Change in Stiffness.- 3.9 Beam Subjected to Concentrated Loads.- 3.10 Solutions by Green's Functions.- 3.11 Tapered Beam Solution Using Galerkin's Method.- 3.12 Problems.- 4. Solutions to Problems of Rectangular Plates.- 4.1 Some General Solutions to the Biharmonic Equation.- 4.2 Double Series Solution (Navier Solution).- 4.3 Single Series Solution (Method of M. Levy).- 4.4 Example of Plate with Edges Supported by Beams.- 4.5 Summary.- 4.6 References.- 4.7 Problems.- 5. Thermal Stresses in Plates.- 5.1 General Considerations.- 5.2 Derivation of the Governing Equations for a Thermoelastic Plate.- 5.3 Boundary Conditions.- 5.4 General Treatment of Plate Nonhomogeneous Boundary Conditions.- 5.5 Thermoelastic Effects on Beams.- 5.6 Self-Equilibration of Thermal Stresses.- 5.7 References.- 5.8 Problems.- 6. Circular Plates.- 6.1 Introduction.- 6.2 Derivation of the Governing Equations.- 6.3 Axially Symmetric Circular Plates.- 6.4 Solutions for Axially Symmetric Circular Plates.- 6.5 Circular Plate, Simply Supported at the Outer Edge, Subjected to a Uniform Lateral Loading, p0.- 6.6 Circular Plate, Clamped at the Outer Edge, Subjected to a Uniform Lateral Loading, p0.- 6.7 Annular Plate, Simply Supported at the Outer Edge, Subjected to a Stress Couple, M, at the Inner Boundary.- 6.8 Annular Plate, Simply Supported at the Outer Edge, Subjected to a Shear Resultant, Q0, at the Inner Boundary.- 6.9 General Remarks.- 6.10 Problems.- 7. Buckling of Columns and Plates.- 7.1 Derivation of the Plate Governing Equations for Buckling.- 7.2 Buckling of Columns Simply Supported at Each End.- 7.3 Column Buckling with Other Boundary Conditions.- 7.4 Buckling of Plates Simply Supported on All Four Edges.- 7.5 Buckling of Plates with Other Loads and Boundary Conditions.- 7.6 References.- 7.7 Problems.- 8. The Vibrations of Beams and Plates.- 8.1 Introduction.- 8.2 Natural Vibrations of Beams.- 8.3 Natural Vibrations of Plates.- 8.4 Forced Vibrations of Beams and Plates.- 8.5 References.- 8.6 Problems.- 9. Energy Methods in Beams, Columns and Plates.- 9.1 Introduction.- 9.2 Theorem of Minimum Potential Energy.- 9.3 Analysis of Beams Subjected to a Lateral Load.- 9.4 The Buckling of Columns.- 9.5 Vibration of Beams.- 9.6 Minimum Potential Energy for Rectangular Plates.- 9.7 The Buckling of a Plate under Uniaxial Load, Simply Supported on Three Sides, and Free on an Unloaded Edge.- 9.8 Functions to Assume in the Use of Minimum Potential Energy for Solving Beam, Column, and Plate Problems.- 9.9 Problems.- 10. Cylindrical Shells.- 10.1 Cylindrical Shells under General Loads.- 10.2 Circular Cylindrical Shells under Axially Symmetric Loads.- 10.3 Edge Load Solutions.- 10.4 A General Solution for Cylindrical Shells under Axially Symmetric Loads.- 10.5 Sample Solutions.- 10.6 Circular Cylindrical Shells under Asymmetric Loads.- 10.7 Shallow Shell Theory (Donnell's Equations).- 10.8 Inextensional Shell Theory.- 10.9 Membrane Shell Theory.- 10.10 Examples of Membrane Theory.- 10.11 References.- 10.12 Problems.- 11. Elastic Stability of Shells.- 11.1 Buckling of Isotropic Circular Cylindrical Shells under Axially Symmetric Axial Loads.- 11.2 Buckling of Isotropic Circular Cylindrical Shells under Axially Symmetric Axial Loads and an Internal Pressure.- 11.3 Buckling of Isotropic Circular Cylindrical Shells under Bending.- 11.4 Buckling of Isotropic Circular Cylindrical Shells under Lateral Pressures.- 11.5 Buckling of Isotropic Circular Cylindrical Shells in Torsion.- 11.6 Buckling of Isotropic Circular Cylindrical Shells under Combined Axial Loads and Bending Loads.- 11.7 Buckling of Isotropic Circular Cylindrical Shells under Combined Axial Load and Torsion.- 11.8 Buckling of Isotropic Circular Cylindrical Shells under Combined Bending and Torsion.- 11.9 Buckling of Isotropic Circular Cylindrical Shells under Combined Bending and Transverse Shear.- 11.10 Buckling of Isotropic Circular Cylindrical Shells under Combined Axial Compression, Bending and Torsion.- 11.11 Buckling of Isotropic Spherical Shells under External Pressure.- 11.12 Buckling of Anisotropic and Sandwich Cylindrical Shells.- 11.13 References.- 11.14 Problems.- 12. The Vibration of Cylindrical Shells.- 12.1 Governing Differential Equations for Natural Vibrations.- 12.2 Hamilton's Principle for Determining the Natural Vibrations of Cylindrical Shells.- 12.3 Reference.- Appendix 1. Properties of Useful Engineering Materials.- Appendix 2. Answers to Selected Problems.
64 citations
TL;DR: In this article, a general finite element model is proposed to deal with dynamic theromelastic problems especially with longer transient period, which consists of formulating and solving the problem in the Laplace transform domain by the Finite Element Method (FEM) and then numerically inverting the transformed solution to obtain the time-domain response.
Abstract: A general finite-element model is proposed to deal with dynamic theromelastic problems especially with longer transient period. The method consists of formulating and solving the problem in the Laplace transform domain by the Finite Element Method (FEM) and then numerically inverting the transformed solution to obtain the time-domain response. Therefore, the transient solutions at any time could be evaluated directly. A number of examples are presented which demonstrate the accuracy, efficiency, and versatility of the proposed method, and show the effects of relaxation times, inertia, and thermoelastic coupling terms.
58 citations
TL;DR: In this article, the mixed boundary-value problem of a welded (and smooth) surface footing is reduced to a set of coupled Fredholm integral equations of the first kind and a numerical solution is provided.
TL;DR: In this article, a solution for the thermoelastic stress field due to obstruction of a uniform heat flux by a plane crack in a generally anisotropic body is given.
Abstract: A solution is given for the thermoelastic stress field due to the obstruction of a uniform heat flux by a plane crack in a generally anisotropic body. A Green's func tion formulation is used to reduce the problem to a set of singular integral equations which are solved in closed form. When the crack is assumed to be traction free, the crack opening displacement is found to be negative over one half of the crack unless a sufficiently large far field tensile stress is superposed. The problem is, therefore, reformulated assuming a contact zone at one crack tip. The extent of this zone and the stress intensity factors in all three modes at each crack tip are obtained as func tions of the applied stress and heat flux.
TL;DR: In this paper, single integral expressions are derived for stresses and strains, which are analytically evaluated on axis at the surface and far from the laser-heated region (for a laser spot size≫absorption depth), and numerically evaluated for the example of laser heating of a silicon substrate.
Abstract: The thermoelastic equations are solved for laser heating of a semi‐infinite elastic medium by a focused TEM00 Gaussian beam. Single integral expressions are derived for stresses and strains, which are analytically evaluated on axis at the surface and far from the laser‐heated region (for a laser spot size≫absorption depth), and numerically evaluated for the example of laser heating of a silicon substrate. This analysis is extended to the case of laser heating of thin films on substrates. Use of these stress and strain profiles suggests that dislocations may form at the surface during high‐temperature laser processing of silicon at scan speeds typically used in direct laser writing. Also the elastic strains induced during laser heating shift phonon frequencies from their thermal equilibrium values, thereby complicating the use of Raman scattering as an optical probe of temperature. This is shown to be particularly significant for laser heating of silicon thin films on fused silica substrates and not very i...
TL;DR: In this article, the thermodynamic properties of the martensitic transformation in shape-memory alloys were investigated and the usual hysteretic subloop behavior during partial cycling was obtained for the first time by calorimetry.
Abstract: The thermoelastic martensitic transformation in shape-memory alloys is studied thermodynamically. Calorimetric experiments on the Cu─Zn─A1 alloy system reveal that the transformation takes place with a practically negligible entropy production. The usual hysteretic subloop behaviour during partial cycling is obtained for the first time by calorimetry. An analysis of the measurements gives the quantitative behaviour of elastic and dissipative energies with the volume fraction of martensite.
TL;DR: In this paper, the authors presented a method for obtaining the individual stress components from this bulk stress data by taking into account the boundary conditions and the expected form of the stress distribution, and the particular case of a strip loaded across part of its boundary is treated in detail.
TL;DR: In this paper, the transient behavior and stability of a system consisting of two thermally conducting elastic rods in contact on their end faces, the other ends of the rods being built-in to two rigid walls which are maintained at different temperatures.
TL;DR: In this paper, numerical techniques are used to calculate the effect on thermal stresses of the shape of the solid-liquid interface during Czochralski crytal growth, where the interface is modelled as parabolic and characterized by the magnitude of the maximum deviation from planarity.
TL;DR: A photothermal probing technique for a clamped thin plate sample that uses thermoelastic bending, where the irregularity of the plate is detectable nondestructively as changes in amplitude and phase of the flexural vibration.
Abstract: In this paper we report a photothermal probing technique for a clamped thin plate sample that uses thermoelastic bending. Irradiation of the modulated laser light focused on the clamped plate sample generates the flexural vibration caused by thermoelastic bending. By scaning with the focused beam and optically sensing the bending, the irregularity of the plate is detectable nondestructively as changes in amplitude and phase of the flexural vibration. Characteristics of thermoelastic bending are also examined from the viewpoint of bending hot spot theory.
01 Jan 1988
TL;DR: In this paper, generalized constitutive relationships for viscoelastic materials are suggested in which the customary time derivatives of integer order are replaced by derivatives of real order, and such models are shown to be effective in describing the frequency-dependent anelastic behaviour of metals due to thermoelastic or magnetoelastic relaxation.
Abstract: Generalized constitutive relationships for viscoelastic materials are suggested in which the customary time derivatives of integer order are replaced by derivatives of real order. Such models are shown to be effective in describing the frequency-dependent anelastic behaviour of metals due to thermoelastic or magnetoelastic relaxation.
01 Jan 1988
TL;DR: In this paper, a prototype microwave-induced thermoelastic tissue imaging system was designed to acquire and process two-dimensional projections of various sizes test tubes filled with tissue equivalent materials.
Abstract: A prototype microwave-induced thermoelastic tissue imaging system was designed to acquire and process two-dimensional projections of various sizes test tubes filled with tissue equivalent materials. A test object is immersed in a tank of water at whose surface single microwave pulses of 2 mu s at a carrier frequency of 2450 MHz are launched. Thermoelastic waves induced at the water surface are detected, on propagating through the object material, by a 20*20 piezoelectric transducer array at the bottom of the water tank. A computer-controlled data acquisition system samples and converts the amplified and bandlimited signals into digital form. The system produces images interactively through the use of image processing techniques. Results are presented to demonstrate the potential use of microwave-induced thermoelastic waves as a possible medical imaging modality. >
TL;DR: In this paper, the theory of generalized thermoelasticity is used to solve a boundary-value problem of an isotropic elastic half-space with its plane boundary held rigidly fixed and subjected to a sudden temperature increase.
Abstract: In this paper the theory of generalized thermoelasticity is used to solve a boundary-value problem of an isotropic elastic half-space with its plane boundary held rigidly fixed and subjected to a sudden temperature increase. Approximate small time solution is obtained by using the Laplace transform method. Numerical values of stress and temperature have been obtained. It has been noticed that the displacement is continuous and that there are two discontinuities in both the stress and temperature functions.
TL;DR: In this paper, the temperature distribution in the growth system and the elastic thermal stress field in the growing crystal were calculated at three stages of the solidification process, and it was shown that at early stages of growth excessive stresses are generated as the cone emerges from the encapsulant, and at later times the maximum stresses occur close to the solidization interface and the region where the crystal emerges from encapsULant.
01 Jan 1988
TL;DR: In this paper, the authors analyzed the dynamics of a long tether connecting two spacecraft in earth orbit, one of the spacecraft having dominant mass, and they considered the material damping of the tether.
Abstract: This paper analyzes the dynamics of a long tether connecting two spacecraft in earth orbit, one of the spacecraft having dominant mass. In particular, it considers the material damping of the tether. The nominal position of the tether is stabilized by the gravity gradient such that it is aligned with the local vertical. The tether is modeled as a viscoelastic flexible continuum. Modal frequencies are derived in an analytical approximation form. Damping ratios are estimated according to the linear model calibrated by ground measurements. The results show that, with properly chosen tether material and braiding structure, longitudinal vibrations of the tethered system are well damped.
TL;DR: In this article, normalized spherical scattering amplitudes are introduced for the displacement as well as the temperature field, via asymptotic analysis of appropriate integral representations, with the exception of the scattering amplitude corresponding to the transverse elastic wave.
Abstract: A plane thermoelastic wave, propagating in an isotropic and homogeneous, medium in the absence of body forces and heat sources, is scattered by a smooth, convex and bounded three-dimensional body. The body could be a rigid scatterer at constant temperature, a rigid scatterer at thermal insulation, a cavity at constant temperature, or a cavity at thermal insulation, while in all cases the Kupradze’s radiation conditions are assumed to hold at infinity. The second law of thermodynamics imposes an attenuation of the elastothermal and the thermoelastic waves, which is reflected upon the lack of symmetry of the unified differential operator governing the Biot theory of dynamic thermoelasticity. Normalized spherical scattering amplitudes are introduced for the displacement as well as the temperature field, via asymptotic analysis of appropriate integral representations. With the exception of the scattering amplitudes corresponding to the transverse elastic waves, all the other scattering amplitudes involve atte...
TL;DR: Analyse du debut et de la fin des transformations β→martensite and martensite→β. Estimation de la variation de volume associee a la transformation as mentioned in this paper.
TL;DR: In this article, the singular characteristics of heat flux in the vicinity of the crack-tip for two dimensional transient thermoelastic fracture problems subjected to general heat transfer conditions at crack surfaces were investigated.
Abstract: This paper presents the singular characteristics of heat flux in the vicinity of the crack-tip for two dimensional transient thermoelastic fracture problems subjected to general heat transfer conditions at crack surfaces. Based on a restricted variational principle, a rigorous hybrid finite element procedure is then developed to perfectly describe the singularities of heat flux and thermal stress induced at the crack-tip. For verification purposes, the examples of transient thermoelastic problems with insulated crack surfaces are first analyzed. Excellent agreements between the computed results and referenced solutions can be drawn. To evaluate the influence of heat convection and radiation on the computation of temperature distributions and thermal stress intensity factors, several numerical examples are also presented.
TL;DR: In this paper, the inverse problem of recovering the elastic constants of a specimen from experimental waveforms recorded on and off-epicenter is considered, and an algorithm based on nonlinear least squares fitting is presented and has been used on experimental displacement signals recorded on an aluminum plate with a Michelson interferometer.
Abstract: Illumination of a specimen by a pulsed focused laser is known to induce elastic waves, and models are available for both cases of thermoelastic generation and liquid evaporation. In this article, the inverse problem of recovering the elastic constants of a specimen from experimental waveforms recorded on‐ and off‐epicenter is considered. An algorithm, based on nonlinear least‐squares fitting, is presented and has been used on experimental displacement signals recorded on an aluminum plate with a Michelson interferometer. The choice of the receiver position is discussed and experimental results are given.
TL;DR: In this article, a shape sensitivity analysis is performed for a dynamically loaded nonlocal thermoelastic solid body, considering a general integral functional of system's response in a finite interval of time, the total variation of the functional with respect to shape variations is obtained through the adjoint variable method and the material derivative concept of structural optimization.