Showing papers on "Thermoelastic damping published in 2022"

Sensitive carbon monoxide detection based on light-induced thermoelastic spectroscopy with a fiber-coupled multipass cell [Invited]

Abstract: A sensor based on light-induced thermoelastic spectroscopy (LITES) with a fiber-coupled multipass cell was demonstrated for carbon monoxide (CO) detection. The fiber-coupled structure has the merits of reducing optical interference and difficulty in optical alignment and increasing system robustness. A 1.57 μm continuous wave distributed feedback diode laser was used as the excitation source. A minimum detection limit of 9 ppm was obtained, and the calculated normalized noise equivalent absorption coefficient was 1.15 × 10−7 cm−1 · W · Hz−1=2. The reported CO-LITES sensor showed excellent linear concentration response and system stability.

Highly sensitive methane detection based on light-induced thermoelastic spectroscopy with a 2.33 µm diode laser and adaptive Savitzky-Golay filtering

Abstract: In this manuscript, a highly sensitive methane (CH4) sensor based on light-induced thermoelastic spectroscopy (LITES) using a 2.33 µm diode laser with high power is demonstrated for the first time. A quartz tuning fork (QTF) with an intrinsic resonance frequency of 32.768 kHz was used to detect the light-induced thermoelastic signal. A Herriot multi-pass cell with an effective optical path of 10 m was adopted to increase the laser absorption. The laser wavelength modulation depth and concentration response of this CH4-LITES sensor were investigated. The sensor showed excellent long term stability when Allan deviation analysis was performed. An adaptive Savitzky-Golay (S-G) filtering algorithm with χ2 statistical criterion was firstly introduced to the LITES technique. The SNR of this CH4-LITES sensor was improved by a factor of 2.35 and the minimum detection limit (MDL) with an integration time of 0.1 s was optimized to 0.5 ppm. This reported CH4-LITES sensor with sub ppm-level detection ability is of great value in applications such as environmental monitoring and industrial safety.

Super tiny quartz-tuning-fork-based light-induced thermoelastic spectroscopy sensing.

Abstract: In this Letter, a sensitive light-induced thermoelastic spectroscopy (LITES)-based trace gas sensor by exploiting a super tiny quartz tuning fork (QTF) was demonstrated. The prong length and width of this QTF are 3500 µm and 90 µm, respectively, which determines a resonant frequency of 6.5 kHz. The low resonant frequency is beneficial to increase the energy accumulation time in a LITES sensor. The geometric dimension of QTF on the micrometer scale is advantageous to obtain a great thermal expansion and thus can produce a strong piezoelectric signal. The temperature gradient distribution of the super tiny QTF was simulated based on the finite element analysis and is higher than that of the commercial QTF with 32.768 kHz. Acetylene (C2H2) was used as the analyte. Under the same conditions, the use of the super tiny QTF achieved a 1.64-times signal improvement compared with the commercial QTF. The system shows excellent long-term stability according to the Allan deviation analysis, and a minimum detection limit (MDL) would reach 190 ppb with an integration time of 220 s.

Revisiting Cu-based shape memory alloys: Recent developments and new perspectives

Abstract: Cu-based shape memory alloys belong to one important class of functional alloys, presenting shape memory effect and superelasticity due to their reversible martensitic transformation. Although they have been extensively studied since the middle of the last century, there are still many challenges to be solved. In the last decades, these alloys were extensively studied regarding new compositions, processing routes, phase transformation, mechanical and functional properties. Aspects of the thermoelastic phase transformation have been described using thermodynamic and thermo-mechanical studies, while the role of metallurgical features (such as grain size and morphology, ordering, precipitates and second phases) have been described mainly by phenomenological approach. In this sense this review discusses the advances in the general fundamentals of Cu-based shape memory alloys, the recent developments in processing routes, compositions, and applications in the last years.

Revisiting Cu-based shape memory alloys: Recent developments and new perspectives

Abstract: Abstract Cu-based shape memory alloys belong to one important class of functional alloys, presenting shape memory effect and superelasticity due to their reversible martensitic transformation. Although they have been extensively studied since the middle of the last century, there are still many challenges to be solved. In the last decades, these alloys were extensively studied regarding new compositions, processing routes, phase transformation, mechanical and functional properties. Aspects of the thermoelastic phase transformation have been described using thermodynamic and thermo-mechanical studies, while the role of metallurgical features (such as grain size and morphology, ordering, precipitates and second phases) have been described mainly by phenomenological approach. In this sense this review discusses the advances in the general fundamentals of Cu-based shape memory alloys, the recent developments in processing routes, compositions, and applications in the last years. Graphical abstract

Mathematical Modeling and Analytical Solution of Thermoelastic Stability Problem of Functionally Graded Nanocomposite Cylinders within Different Theories

Abstract: Revolutionary advances in technology have led to the use of functionally graded nanocomposite structural elements that operate at high temperatures and whose properties depend on position, such as cylindrical shells designed as load-bearing elements. These advances in technology require new mathematical modeling and updated numerical calculations to be performed using improved theories at design time to reliably apply such elements. The main goal of this study is to model, mathematically and within an analytical solution, the thermoelastic stability problem of composite cylinders reinforced by carbon nanotubes (CNTs) under a uniform thermal loading within the shear deformation theory (ST). The influence of transverse shear deformations is considered when forming the fundamental relations of CNT-patterned cylindrical shells and the basic partial differential equations (PDEs) are derived within the modified Donnell-type shell theory. The PDEs are solved by the Galerkin method, and the formula is found for the eigenvalue (critical temperature) of the functionally graded nanocomposite cylindrical shells. The influences of CNT patterns, volume fraction, and geometric parameters on the critical temperature within the ST are estimated by comparing the results within classical theory (CT).

Generalized thermoelasticity model for thermoelastic damping in asymmetric vibrations of nonlocal tubular shells

Abstract: The present article intends to provide a size-dependent generalized thermoelasticity model and closed-form solution for thermoelastic damping (TED) in cylindrical nanoshells. With the aim of incorporating size effect within constitutive relations and heat conduction equation, nonlocal elasticity theory and Guyer–Krumhansl (GK) heat conduction model are exploited. Donnell–Mushtari–Vlasov (DMV) equations are also employed to model the cylindrical nanoshell. By adopting asymmetric simple harmonic form for oscillations of nanoshell and merging the motion, compatibility and heat conduction equations, the nonclassical frequency equation is extracted. By solving this eigenvalue problem and separating the real and imaginary parts of complex frequency analytically, an explicit expression is given to estimate the magnitude of TED in cylindrical nanoshells with arbitrary boundary conditions. Good agreement between the results of this study in special cases and those available in the literature affirms the validity of present formulation. In the following, for some vibration modes, a detailed parametric study is conducted to illuminate the determining role of structural and thermal nonlocal parameters in the amount of TED in simply-supported cylindrical nanoshells. The augmentation of difference between classical and nonclassical results by reduction in dimensions of nanoshell confirms the small-scale effect on TED value at nanoscales. • A closed-form expression for evaluating the amount of thermoelastic damping (TED) in cylindrical nanoshells is given. • The nonlocal elasticity theory and the Guyer-Krumhansl (GK) heat conduction model are used. • Comparison studies are conducted to check the validity of presented formulation. • Parametric studies are done on the results given by classical and nonclassical continuum theories and heat transfer models. • Detailed numerical results are provided to survey the effect of some parameters like vibration mode on TED value.

Third‐Order Padé Thermoelastic Constants of Solid Rocks

Abstract: Classical third-order thermoelastic constants are generally derived from the theory of small-amplitude acoustic waves in isotropic materials during heat treatments. Investigating higher-order thermoelastic constants for higher temperatures is challenging owing to the involvement of the number of unknown parameters. These Taylor-type thermoelastic constants from the classical thermoelasticity theory are formulated based on the Taylor series of the Helmholtz free energy density for preheated crystals. However, these Taylor-type thermoelastic models are limited even at low temperatures in characterizing the temperature-dependent velocities of elastic waves in solid rocks as a polycrystal compound of different mineral lithologies. Thus, we propose using the Padé rational function to the total thermal strain energy function. The resulting Padé thermoelastic model gives a reasonable theoretical prediction for acoustic velocities of solid rocks at a higher temperature. We formulate the relationship between the third-order Padé thermoelastic constants and the corresponding higher-order Taylor thermoelastic constants with the same accuracy. Two additional Padé coefficients and can be calculated using the second-, third-, and fourth-order Taylor thermoelastic constants associated with the Brugger's constants, which are consistent with those obtained by fitting the experimental data of polycrystalline material. The third-order Padé thermoelastic model (with four constants) is validated by the fourth-order Taylor thermoelastic prediction (with six constants) with ultrasonic measurements for polycrystals (olivine samples) and solid rocks (sandstone, granite, and shale). The results demonstrate that the third-order Padé thermoelastic model can characterize thermally induced velocity changes more accurately than the conventional third-order Taylor thermoelastic prediction (with four constants), especially for solid rocks at high temperatures. The Padé approximation could be considered a more accurate and universal model in describing thermally induced velocity changes for polycrystals and solid rocks.

Boundary Element and Sensitivity Analysis of Anisotropic Thermoelastic Metal and Alloy Discs with Holes

Abstract: The main aim of this paper was to develop an advanced processing method for analyzing of anisotropic thermoelastic metal and alloy discs with holes. In the boundary element method (BEM), the heat impact is expressed as an additional volume integral in the corresponding boundary integral equation. Any attempt to integrate it directly will necessitate domain discretization, which will eliminate the BEM’s most distinguishing feature of boundary discretization. This additional volume integral can be transformed into the boundary by using branch-cut redefinitions to avoid the use of additional line integrals. The numerical results obtained are presented graphically to show the effects of the transient and steady-state heat conduction on the quasi-static thermal stresses of isotropic, orthotropic, and anisotropic metal and alloy discs with holes. The validity of the proposed technique is examined for one-dimensional sensitivity, and excellent agreement with finite element method and experimental results is obtained.

Pulsed Laser Excited Photoacoustic Effect for Disease Diagnosis and Therapy.

Abstract: Pulsed laser can excite light absorber to generate photoacoustic (PA) effect, that is, when the absorber is irradiated with pulsed laser, the absorbed light energy is converted into local heat to cause rapid thermoelastic expansion and generate acoustic wave. The generated PA signal has been widely employed for the diagnosis of many diseases with superb contrast, high penetrability and sensitivity. In addition, with the increase of pulsed laser energy, the resulting PA shockwave and cavitation can promote efficient drug release at lesion sites to potentiate the resulting therapeutic efficacy. Furthermore, the PA shockwave/cavitation can mechanically inhibit disease and produce reactive species. In this Concept article, the principle and research status of pulsed laser excited disease theranostics are briefly summarized, extra suggestions are proposed to inspire extensive PA probes and photodynamic materials as well as novel methodologies.

On the role of the microstructure in the deformation of porous solids

Abstract: This study explores the role that the microstructure plays in determining the macroscopic static response of porous elastic continua and exposes the occurrence of position-dependent nonlocal effects that are strictly correlated to the configuration of the microstructure. Then, a nonlocal continuum theory based on variable-order fractional calculus is developed in order to accurately capture the complex spatially distributed nonlocal response. The remarkable potential of the fractional approach is illustrated by simulating the nonlinear thermoelastic response of porous beams. The performance, evaluated both in terms of accuracy and computational efficiency, is directly contrasted with high-fidelity finite element models that fully resolve the pores' geometry. Results indicate that the reduced-order representation of the porous microstructure, captured by the synthetic variable-order parameter, offers a robust and accurate representation of the multiscale material architecture that largely outperforms classical approaches based on the concept of average porosity.

An analytical integration Legendre polynomial series approach for Lamb waves in fractional order thermoelastic multilayered plates

Abstract: The Legendre polynomial series approach (LPSA) has been widely used to solve guided wave propagation in various structures since 1999. The LPSA directly introduces the boundary conditions into the control equations through the rectangular window function. However, in the solving process, the Legendre polynomial series, the rectangular window function, and their derivatives are introduced into the integral kernel functions, which results in a lot of CPU time on the abundant numerical integration calculations. To overcome this defect, an analytical integration Legendre polynomial series approach (AILPSA) is presented and is used to solve the Lamb waves in fractional order thermoelastic multilayered plates. Coupled wave equations and heat conduction equation are solved by the AILPSA and the LPSA, respectively. Comparison between two approaches indicates the computational efficiency of the AILPSA is improved by more than 90%. In addition, a backward error estimation is given in the convergency analysis to make up for the deficiency of the numerical experiments. Finally, the influence of fractional order on the thermoelastic Lamb wave is discussed.

Viscoelastic initially stressed microbeam heated by an intense pulse laser via photo-thermoelasticity with two-phase lag

Abstract: This work aims to assess the response of viscoelastic Kelvin–Voigt microscale beams under initial stress. The microbeam is photostimulated by the light emitted by an intense picosecond pulsed laser. The photothermal elasticity model with dual-phase lags, the plasma wave equation and Euler–Bernoulli beam theory are utilized to construct the system equations governing the thermoelastic vibrations of microbeams. Using the Laplace transform technique, the problem is solved analytically and expressions are provided for the distributions of photothermal fields. Taking aluminum as a numerical example, the effect of the pulsed laser duration coefficient, viscoelasticity constants and initial stress on photothermal vibrations has been studied. In addition, a comparison has been made between different models of photo-thermoelasticity to validate the results of the current model. Photo-microdynamic systems might be monolithically integrated on aluminum microbeams using microsurface processing technology as a result of this research.

Thermal plane waves in unbounded non-local medium exposed to a moving heat source with a non-singular kernel and higher order time derivatives

Abstract: In this paper, the thermoelastic characteristics of a nonlocal unbounded viscoelastic medium due to an instantaneous heat source is investigated by considering a modified dual-phase-lag model with higher-order time derivatives. The fractional derivative and Eringen's non-local theory are also applied in the considered model. To extend the application of the classical Kelvin-Voigt model, a fractional derivative operator with non-single kernels based on the Atangana and Baleanu's concept is proposed. After applying the Laplace transform method, the governing systems of equations are expressed as vector-matrix differential form and solved by constructing an eigenvalue problem. Some comparative results are presented to analyze the effects of heat source velocity, nonlocal parameter, structural viscoelastic coefficients, phase lags, fractional and higher-order parameters on the behavior of physical fields.

Nonlinear Thermoelastic Numerical Frequency Analysis and Experimental Verification of Cutout Abided Laminated Shallow Shell Structure

Abstract: The cutout and temperature loading influences on the nonlinear frequencies of the laminated shell structures are predicted numerically using two different types of geometrical nonlinear strain-displacement relationships to count the large deformation. The displacement of any generic point on the structural panel is derived using the third-order shear deformation theory (TSDT). Moreover, the direct iterative method has been adopted to obtain the nonlinear eigenvalues in conjunction with the isoparametric finite element (FE) steps. The present analysis includes the effect of temperature and the temperature-dependent composite elastic properties on the thermoelastic frequencies. This study intends to establish the Green- Lagrange type of nonlinear strain's efficacy in computing the nonlinear frequency of layered structure with and without cutout instead of von-Karman strain kinematics. The numerical model's validity has been established by comparing the results to previously published results. In addition, experimentally obtained fundamental frequency values of few modes are compared to numerical proposed numerical results under the thermal loading. Finally, the effects of cutout (shape and size) and the associated structural geometrical parameters on the nonlinear thermal frequency responses of the laminated structure are expressed in the final output form.

Non-integer order analysis of electro-magneto-thermoelastic with diffusion and voids considering Lord–Shulman and dual-phase-lag models with rotation and gravity

Abstract: This study developed the effect of the diffusion with voids within the generalized thermoplastic half-space having initial stress, rotation, a field of electromagnetism, and gravity for the following two models: Lord–Shulman and dual-phase-lag. The authors expressed the study’s problem in the dimensionless form and resolved it analytically by the normal mode analysis and Lame’s potential method. The analytical solutions for the temperature, stresses, displacements, concentration of diffusion, and volume fraction field were gained in the physical field using the analysis of normal mode. The outcome of all parameters was given and portrayed graphically. Comparisons were made with the findings gained in appearance and nonappearance of the examined variables and presented in graphs. The study reported that the impacts of the initial stress, diffusion, gravity, voids, rotation, and electromagnetic field are obvious on the phenomenon. The impact of fractional calculus and a comparison between the presence and absence of fractal calculus were discussed to clear the physical meaning of the fractional parameter and their related applications in biology, geophysics, etc.

Thermoelastic stability of CNT patterned conical shells under thermal loading in the framework of shear deformation theory

Abstract: Abstract This study presents the thermoelastic stability of carbon nanotube (CNT) patterned composite conical shells in the framework of shear deformation theory (ST). The study includes two different boundary value problems. As the material properties are independent of temperature, the truncated conical shell is assumed to be under thermal load, and when the material properties are temperature dependent, the conical shell is assumed to be under axial compressive load. The modified Donnell-type shell theory is used to derive the basic equations for CNT patterned truncated conical shells. The Galerkin method is applied to the basic equations to find the critical temperature and critical axial load expressions of CNT patterned composite truncated conical shells in the framework of ST. The effect of changes in CNT patterns, volume fraction, radius-to-thickness and length-to-thickness ratios, as well as the half-peak angle on critical parameters within the ST, are estimated by comparison with classical shell theory (CT).

Boundary element analysis of rotating functionally graded anisotropic fiber-reinforced magneto-thermoelastic composites

Abstract: Abstract The primary goal of this article is to implement a dual reciprocity boundary element method (DRBEM) to analyze problems of rotating functionally graded anisotropic fiber-reinforced magneto-thermoelastic composites. To solve the governing equations in the half-space deformation model, an implicit–implicit scheme was utilized in conjunction with the DRBEM because of its advantages, such as dealing with more complex shapes of fiber-reinforced composites and not requiring the discretization of the internal domain. So, DRBEM has low RAM and CPU usage. As a result, it is adaptable and effective for dealing with complex fiber-reinforced composite problems. For various generalized magneto-thermoelasticity theories, transient temperature, displacements, and thermal stresses have been computed numerically. The numerical results are represented graphically to demonstrate the effects of functionally graded parameters and rotation on magnetic thermal stresses in the fiber direction. To validate the proposed method, the obtained results were compared to those obtained using the normal mode method, the finite difference method, and the finite element method. The outcomes of these three methods are extremely consistent.