Thermoelastic Effect Research Articles

The influence of the volume fraction of meat in dumplings on their cooking time

Based on the studied literature, the aim was to investigate the influence of the volume fraction of meat in meat dumplings (pelmeni) and the number of dumplings on their cooking time, as well as to analyze the physico-mathematical and technical aspects to be taken into account (or not) within the framework of the planned experiment. To achieve this goal, the following tasks were set: to conduct experimental studies, to describe the assumptions that need to be accepted when performing the study and to conduct theoretical studies (numerical experiments, using the finite element method). When conducting experiments, dumplings of well-known brands, the names of which were conventionally labeled as “SK”, “SZ”, “RE”, “TS”, were chosen as objects of research. The need to study the dumplings of well-known brands is justified by both consumer interest and a smaller variability of product parameters, which increases the reproducibility of the results of the study. As assumptions adopted in real experiments, the authors emphasize the following ones: distilled water is used in cooking, the volume of a dumpling does not change during cooking, the biochemical composition of the filling can be neglected. As a result of the theoretical analysis, the following assumptions were made: the study of dumpling cooking does not take into account the resistance forces, i. e., turbulent and convective flows, as well as thermo-elastic effects; the time of dumpling floating to the surface is negligibly small; "approximation of initial values" — geometric, physico-chemical parameters of the dumpling do not change during cooking. Cooking time of 1, 5, 10 dumplings of known brands was obtained on the basis of numerical experiments. Using real experiments, the time from immersion of the dumplings in water to their floating to the surface was investigated. As a result of numerical experiments it has been found that the time of heating the center of the dumpling of known brands to the temperature of protein denaturation differs from the time of floating to the surface by about 360 seconds. Consequently, after floating to the surface, the dumplings of known brands need about six more minutes of cooking time until they are fully cooked.

Analysis of bioheat transfer with thermoelastic effect

Analysis of bioheat transfer with thermoelastic effect

Enhanced Dye-Sensitized Mechanosensation Utilizing Pulsed and Digitally Modulated Light.

The generation of pressure perturbations in matter stimulated by pulsed light is a method widely recognized as the photoacoustic or light-induced thermoelastic effect. In a series of psychophysical experiments, the robustness of the tactile perception generated with a variety of light sources is examined: a diverging pulsed laser used for photoacoustic tomography optical parameter oscillation (OPO), a miniature diode laser (MDL), and a commercial digital light processing (DLP) projector. It is demonstrated that participants can accurately detect, categorically describe the sensations, and discern the direction of pulsed light travel. High detection accuracy is reported as follows: (d' = 4.95 (OPO); d' = 2.78 (modulated MDL); d' = 2.99 (DLP)) of the stimulus on glabrous skin coated with a thin layer of dye absorber. For all light sources, the predominant sensation is felt as vibration at the distal phalanx (i.e., fingertip, 55.21-57.29%) and the proximal phalanx (41.67-44.79%). At the fingertip, thermal sensations are perceived less frequently than mechanical ones. Moreover, these haptic effects are preserved under a wide range of pulse widths, spot sizes, optical energies, and wavelengths of the light sources. This form of sensory stimulation demonstrates a generalizable non-contact, non-optogenetic, in situ activation of the mechanosensorysystem.

Investigation on machinability of SiCp/Al composites under the synergistic effect of pulsed laser assisted and ultrasonic elliptical vibration cutting

While SiCp/Al composites are widely used in engineering applications owing to their excellent material properties, the traditional machining of SiCp/Al composites remains challenging, mainly in terms of poor surface quality and severe tool wear. In this study, a multi-energy field assisted cutting method—pulsed laser-assisted ultrasonic elliptical vibration cutting (PLA-UEVC)—for precision and high-efficiency machining of SiCp/Al composites is introduced. In this method, the intermittent impact cutting effect caused by the tool's ultrasonic frequency elliptical vibration, pulsed-laser-induced material-generated thermoelastic excitation effect, and transient temperature field synergistically work together to enhance the machinability of SiCp/Al composites. Temperature-field simulations were first utilized to simulate the temperature under suitable pulsed laser parameters. Comparative experiments with different volume fractions and particle sizes under different machining methods were conducted to evaluate the advantages of the proposed composite energy field-assisted machining method in terms of chip modulation, surface quality improvement, and tool performance improvement. The experimental results show that multi-energy field assisted cutting achieves better chip control and obtains shorter, easier-to-break chips than traditional cutting, pulsed laser-assisted cutting, and ultrasonic vibration-assisted cutting. The cutting forces of the three industrial-grade SiCp/Al6061 composites with different material properties were significantly reduced (by more than 55 %), with a surface roughness of less than 30 nm obtained for all three composites, effectively suppressing surface defects such as particle failure, thermal damage, and residual height caused by tool vibration. In addition, multi-energy field assisted cutting effectively minimized the abrasive and diffusive wear of the tool and reduced the adhesion phenomenon on the back face of the tool. These findings provide an important theoretical basis and practical machining guidance for multi-energy-field synergistic machining to improve the machinability of SiCp/Al composites.

Temperature mapping methods for thermoelastic analyses of the ARIEL spacecraft payload module

The ARIEL mission is a European space project that aims to detect exoplanets with a spacecraft orbiting around the L2 point of the Sun-Earth system. The main payload consists of a Cassegrain telescope composed of mirrors that reflect and concentrate the incoming light from the deep space observations to finally guide it to the detectors. As in many other space missions, a dedicated complex assessment is established during the design phase to evaluate the impact on the optical performance caused by thermoelastic effects, which involves the coordinated work of the thermal, structural, and optical engineers. Despite that well-known and standardized processes and tools are established separately in each involved area, there is a lack of standardization about the way of exchanging the data between them, where additional calculations are required in some cases. This work focuses on the temperature mapping, which is the intermediate step between thermal and structural analyses, where temperatures are transferred to the structural model. The main difficulty of this process is related to the differences in modelling methods and approaches between both models, being necessary the development of an adequate algorithm to find the most accurate transfer of temperatures. This paper shows two different options for temperature mapping, detailing the proposed flowcharts. One of these methods requires the performance of an additional thermal conductive analysis, where a new improved procedure has been implemented in this work to solve some computational issues that made its application for large models difficult or even unfeasible. Both temperature mapping methods have been applied to the payload module of the ARIEL spacecraft, comparing the output results in terms of temperatures, stresses, forces, and displacements to evaluate their differences.

Quantitative analysis of laser-generated ultrasonic wave characteristics and their correlation with grain size in polycrystalline materials

Abstract The quantitative relationship between nanosecond pulsed laser parameters and the characteristics of laser-generated ultrasonic waves in polycrystalline materials was evaluated. The high energy of the pulsed laser with a large irradiation spot simultaneously generated ultrasonic longitudinal and shear waves at the epicenter under the slight ablation regime. An optimized denoising technique based on wavelet thresholding and variational mode decomposition was applied to reduce noise in shear waves with a low signal-to-noise ratio. An approach for characterizing grain size was proposed using spectral center frequency ratio (SCFR) based on time-frequency analysis. The results have demonstrated that the generation regime of ultrasonic waves is not solely determined by the laser power density; even at high power densities, a high energy with a large spot can generate an ultrasonic waveform dominated by the thermoelastic effect. It is ascribed to the intensification of the thermoelastic effect with the proportional increase in laser irradiation spot area for a given laser power density. Furthermore, both longitudinal and shear wave SCFRs are linearly related to grain size in polycrystalline materials; however, the shear wave SCFR is more sensitive to finer-grained materials. This study holds great significance for evaluating metal material properties using laser ultrasound.

Infrared temperature evolution law and thermal effect mechanism of concrete impact failure

Concrete impact failure can occur quickly and cause severe failure, which is of great significance for effective monitoring of concrete impact failure. Infrared thermal imaging technology possesses the merits of high sensitivity, noncontact, and nondestructive monitoring, rendering it extensively employed in monitoring the stability of concrete structures. However, the infrared radiation temperature (IRT) evolution law and thermal effect mechanism of concrete impact failure are not clear at present. In this study, infrared monitoring experiments were conducted on concrete impact failure and static load failure using drop hammer (DH) testing machines, pressure testing machines, and infrared thermal imagers. The infrared thermal images and the IRT change law of concrete subjected to DH impact failure were analysed. The infrared thermal effect difference and mechanism between DH impact and static load failure were compared. The results indicate that there is an infrared high-temperature point at the impact location of concrete DH impact failure, and both average infrared radiation temperature (AIRT) and maximum infrared radiation temperature (MIRT) increase suddenly. The increase in the MIRT is tens of times that of the AIRT. Compared with that of static load failure, the infrared high-temperature area of concrete DH impact failure is concentrated, while the IRT of static load failure increases overall, and the heating area is large. Moreover, the change in the IRT under DH impact failure is much greater than that under static load failure. The infrared thermal effect of concrete under DH impact failure was mainly composed of the thermoelastic effect, frictional thermal effect and tensile failure endothermic effect. The infrared data obtained for concrete impact failure should focus on the highest and lowest IRT change indicators. The highest IRT corresponds to the impact failure point, and the lowest IRT corresponds to the tensile failure position. The research results provide a new infrared thermal effect approach for monitoring the stability of concrete under impact failure.

Effects of thermoelasticity induced aperture variation on performances of Enhanced geothermal system

Geothermal energy, as one of the renewable energy types, has great potential to balance the variable energy supply from photovoltaic and wind energy types. This, however, requires the development of an Enhanced Geothermal System (EGS). Injecting cold water into deep geo-reservoirs induces thermoelastic deformation and changes the fracture apertures, which may significantly affect the EGS lifetime and energy performance. In this case, this study develops a fully coupled thermal–hydraulic-mechanical model to investigate the impacts of temperature, pressure, and aperture heterogeneity on the alterations of fracture aperture. Then, considering the reservoir lifespan, the research takes a further step into the influence of heterogeneous aperture variation on EGS production temperature and long-term energy performance. Results show that aperture significantly varies once a temperature breakthrough occurs in the production well for both homogeneous and heterogeneous aperture fields. The thermoelasticity-induced aperture variations enhance water flow rate, leading to a considerable increase in reservoir heat production rate, but a shorter EGS lifespan. Furthermore, temperature variation shows a more substantial influence on aperture alteration compared to pressure change. Additionally, a sensitivity analysis indicates that the 30-year total energy output is proportional to the injection/production pressures and injection temperatures. However, the fracture with either excessively large or small initial apertures leads to worse EGS energy performance.

Stability and regularity for double wall carbon nanotubes modeled as Timoshenko beams with thermoelastic effects and intermediate damping

This research studies two systems composed by the Timoshenko beam model for double‐wall carbon nanotubes, coupled with the heat equation governed by Fourier's law. For the first system, the coupling is given by the rotation speed of the vertical filament in the beam from the first beam of Timoshenko and the Laplacian of temperature , where we also consider the damping terms fractionals , , and , where . For this first system, we proved that the semigroup associated to system decays exponentially for all . The second system also has three fractional dampings , , and , with . Furthermore, the couplings between the heat equation and the Timoshenko beams of the double wall carbon nanotubes for the second system are given by the Laplacian of the rotation speed of the vertical filament in the beam of the first beam of Timoshenko and the Lapacian of temperature . For the second system, we prove the exponential decay of the associated semigroup for and also show that this semigroup admits Gevrey classes for , and we finish our investigation proving that is analytic when the parameters .

An extended continuum-mechanics standard linear solid rheology for fluid-saturated porous rock

SUMMARY In a large body of rock-physics research, seismic wave velocity dispersion and attenuation in fluid-saturated porous rock are studied by constructing analytical or numerical models for time- or frequency-dependent dynamic (effective, or viscoelastic) moduli. A key and broadly used model of such kind is the Zener's, or the standard linear solid (SLS). This model is qualitatively successful in explaining many field and laboratory observations and serves as the key element of many generalizations such as the Burgers model for plastic deformations or the generalized SLS explaining band-limited or near-constant seismic attenuation. However, as a physical model of fluid-saturated porous rock, the SLS has several major limitations: disregard of inertial effects, absence of secondary wave modes and lack of key physical parameters such as porosity and Skempton coefficients. Grainy and porous rock is an unconsolidated material in which the effective density is frequency-dependent, and its effects on wave velocities may exceed those of the dynamic modulus. To overcome these limitations of the empirical SLS, we propose a rigorous rheologic model based on classical continuum mechanics and called the extended SLS, or eSLS. This rheology explains the available attenuation and dispersion observations equally well, but it is also close to Biot's model, honours all poroelastic relations, includes inertial effects, and reveals several new physical properties of the material. Detailed comparison of the eSLS and Biot's models gives a physical-mechanism-based classification of wave-induced fluid flow (WIFF) phenomena. In this classification, the so-called ‘global-scale’ flows occur in Biot's type structures within the material, whereas the ‘local-scale’ WIFF occurs in eSLS-type structures. Combining Biot's and eSLS models gives a broad class of rheologies for linear anelastic phenomena within rock with a single type of porosity. The model can be readily generalized to multiple porosities and different types of internal variables, such as describing squirt flows, wetting or thermoelastic effects. Modelling is conducted with relatively little effort, using a single matrix equation similar to a mechanical form of the standard SLS. By combining the eSLS and Biot's models, observations of dynamic-modulus dispersion and attenuation can be inverted for macroscopic mechanical properties of porous materials.

Raman Spectroscopy Analysis for Precise Channel Temperature Estimation in AlGaN/GaN HEMT Devices

In recent years, high-electron-mobility GaN HEMTs have demonstrated significant advancements in applications such as power converters and RF amplifiers. Nevertheless, their thermal reliability poses a notable challenge, placing constraints on their power-handling capacities. This study employs micro-Raman spectroscopy to evaluate the localized self-heating-induced channel temperature. The channel temperature, determined using the single phonon modes of GaN HEMT (E2(H) & A1(LO)), exhibits discrepancies and does not align with device temperature values calculated using the SiC phonon peak near the GaN channel. However, by employing both phonon modes of GaN to decouple the combined effects of joule heating and the thermoelastic effect, accurate channel temperature values are obtained, matching well with those obtained from the SiC phonon peak. The agreement between calculated temperatures from phonon modes and those obtained by heating the device from the back side enhances the credibility of the proposed method.

Analysis of the effect of the direction of reinforcement of a fibrous composite material on the inhomogeneity of localization of deformations and stresses using the method of thermoelastic response

The purpose of the article is to study the effect of the direction of reinforcement of a composite material relative to the cyclic load on the inhomogeneity of stress distribution by the thermal method of non-destructive testing using the thermoelastic effect. This method is widely used in all industries for the control of structural elements and in research work. The degree of stress inhomogeneity is used when choosing the safety factors necessary to ensure the safety of technical objects. In this study, the thermoelastic effect is used to show the possibility of estimating the local distribution of stresses using the temperature field of the test object, proceeding from the linear relation between the temperature of the elastic body and mechanical stresses. The results of studying composite laminates (fibrous filler (fiberglass) with an epoxy matrix) with different laying of fibers with respect to the direction of loading are presented. Four laminate samples were considered: single-layer [0] and [90], three-layer [0]3 and [90]3. Statistical data and estimates of the coefficients of variation, methods of clustering and averaging over the length of the laminates the values of the temperature distribution over the surface of the laminates. The numerical characteristics of the distribution of local temperatures are obtained. It is shown that a more uniform distribution occurs when reinforcing is directed along the direction of the material loading. The integral and local characteristics of the temperature distribution in the samples are compared. The differences in the local temperature distribution depending on the laminate thickness were noted visually for single-layer and three-layer samples. A more uniform distribution of the load is also observed in the direction of reinforcement and with an increase in the number of reinforcement layers. The results obtained lead to the conclusion that the choice of the value of the safety factor, which evaluates the level of stress inhomogeneity, depends on the design features of the laminates. During operation of products made of composite materials in the presence of significant accumulated damage, when the uneven distribution of stresses increases, the levels of safety factors should be adjusted.

Thermoelastic effects in Bragg reflectors as a potential bottleneck for XFELs with megahertz repetition rate

Bragg reflectors are essential for beam transport in X-ray free-electron laser (XFEL) facilities. On interaction with Bragg reflectors, a part of the pulse energy will be absorbed, causing the propagation of displacement waves due to rapid thermal expansion. It is suspected that these waves may cause stability problems for XFELs operating with megahertz repetition rates. Here, we experimentally investigate the displacement of a diamond Bragg reflector induced by an optical ultra-violet laser pulse, simulating XFEL pulses with mJ pulse energy, both at room temperature and cryogenic temperatures. Our experiment shows negligible damping of the displacement waves on µs timescales, which could cause disruption for subsequent XFEL pulses. We compare our measurements to a simulation framework based on the assumptions of local thermodynamic equilibrium and classical mechanics, observing reasonable agreement. Our results show that thermoelastic effects are critical for a reliable stability assessment of Bragg reflectors, but are often overlooked.

Exploring Thermoelastic Effects in Damped Bresse Systems with Distributed Delay

In this work, we consider the one-dimensional thermoelastic Bresse system by addressing the aspects of nonlinear damping and distributed delay term acting on the first and the second equations. We prove a stability result without the common assumption regarding wave speeds under Neumann boundary conditions. We discover a new relationship between the decay rate of the solution and the growth of ϖ at infinity. Our results were achieved using the multiplier method and the perturbed modified energy, named Lyapunov functions together with some properties of convex functions.

Effect of non-local thermoelasticity on diffusion under hydrostatic pressure

AbstractIn this paper, thermoelastic diffusion theory is demonstrated on a two-dimensional half-space problem. The surface is subjected to thermal shock and hydrostatic loads. The chemical potential must be a known function of time. The solution is obtained by the direct method using the Laplace technique and the Fourier exponential transform. Local and non-local thermoelasticity are discussed, and the influence of non-local parameters on the general theory of thermoelastic diffusion is investigated. Chemical potential, concentration, temperature, stress and displacement distributions are calculated numerically and displayed graphically.

TSA and FEM Analysis Applied to CAD/CAM Titanium All-on-Four Prosthesis

Patient with fully edentulous maxillaries often suffer of several disease as an alteration of facial appearance, difficulties in eating, speech, and chews. Fixed and removable prosthesis can be a solution to rehabilitate this issue. The All-on-Four protocol is one of the possible treatment modalities for implant-supported prosthetics. It consists of placing four implants in an intermorainal position, two perpendicular to the occlusal plane and two tilted distally at a 45° angle. This paper aims to assess the stress distribution on an All-on-Four titanium prosthesis by means of a Thermoelastic Stress Analysis (TSA). This full-field non-contact measurement technique allows, through a thermal imaging camera, to observe how the surface temperature of an object changes under the effect of cyclic load. The principle on which thermoelastic analysis is based is the existence of a relationship between deformation, hence applied stress, and temperature change, called the thermoelastic effect. To perform the tests, the prosthesis was fixed to a resin jaw cast that has similar characteristics to the human bone, so that the same damping that would be present under normal working conditions could be accounted for. The distal artificial molar tooth was kept in contact to a narrow screw, which was attached to a Medium-Force (M-Series) Air-Cooled Shakers made by Santek. This shaker generates a sinusoidal load of 800N with a load cell at 10 Hz frequency, which can maintain the temperature variation of the prosthesis constant. A pre-load was applied before starting the tests. To see the change in temperature a Flir A6751SC thermal camera was used, and videos were acquired with a frame rate of 125 Hz and a resolution of 640x512 pixels. From the experimental TSA tests, the trend of the experimental stress concentration on the titanium specimen was detected. The outcomes of the experimental tests were compared to a 3D prosthesis model by Finite Element Analysis (FEM).

Analysis of the temperature evolution in cyclic loading using the thermoelastic effect with plastic deformation

Analysis of the temperature evolution in cyclic loading using the thermoelastic effect with plastic deformation

Problems of modeling elements with shape memory alloys of military equipment

Shape memory alloys (SMAs) are used in various fields, including military equipment, to create means with autonomous or improved properties. It can be especially useful in structural elements that are capable of self-healing after deformations or damage as a result of explosions, impacts or other loads that occur during military operations.
 SMAs are materials that have the ability to remember and restore the accumulated deformation under certain conditions. This makes them particularly useful in robotics, where they can be used to create moving parts, sensors, actuators and other components.
 One of the main applications of SMA in robotics is the creation of moving elements. For example, they can be used to create bendable segments in jobs that require flexibility and mobility. SMAs can be used to create manipulators that allow a robot to easily move and perform tasks in different environments. One of the most important properties of SMAs is their ability to retain their shape during deformation. This makes them useful for building sensors that can detect differences in the shape of an object. SMAs can be used to create pressure sensors that respond to a change in shape under the influence of external pressure. These sensors can be used to develop robots that can recognize objects and distinguish them by shape. SMA can also be used to create actuators. Actuators are components that convert electrical, mechanical, or other types of energy into motion. SMA are materials that have the ability to remember and restore the accumulated deformation under certain conditions. This is achieved due to the peculiarities of their microstructure and thermoelastic effect. When SMA is subjected to thermal influence in the temperature zone where it can transition between two states: austenitic (higher temperature) and martensitic (lower temperature), under an existing external load, the phase strain increases, and with the degree of load, the temperature of the beginning and end of the emerging of straine changes. Each of these states has its own crystal structure and characteristics determined by its chemical composition. The article considers the issue of taking into account the shift of characteristic temperatures under the influence of an external load of SMA in terms of the synthetic theory of irreversible deformation and proposes a non-linear formula for finding the characteristic temperatures of metals with memory during loading. The obtained ratio was used to find the proportion of the new phase and the rate of formation of the new phase as a function of the magnitude of the external load, the rate of loading, the absolute temperature, the rate of temperature change and the characteristic temperatures in terms of the effective temperature.

Phase-Field Modeling of Coupled Thermo-Hydromechanical Processes for Hydraulic Fracturing Analysis in Enhanced Geothermal Systems

Abundant geothermal energy can be harvested from deep, low-permeability rocks using an enhanced geothermal system (EGS) that relies on an artificially created permeable fracture network through cold water injection. In this study, a two-way coupling technique for thermo-hydromechanical modeling was used to simulate hydraulic fracture propagation in an EGS. The transient heat and fluid flow in porous media were modeled using the finite volume method, while hydraulic fracture propagation and interaction with natural fractures were modeled using the variational phase-field method. Our findings underscore the importance of poroelastic and thermoelastic effects on fracture propagation in naturally fractured reservoirs. The results of this study demonstrate that thermo-hydromechanical processes are crucial elements in simulating and optimizing an enhanced geothermal reservoir system.

Experimental Study of Multiple Physical Parameters Monitoring during Uniaxial Loading Process of Sandstone

Aiming at the damage evolution and energy release characteristics of sandstone in failure process, uniaxial and cyclic loading experiments were conducted with the average temperature, infrared temperature field, acoustic emission (AE), and displacement field being monitored simultaneously. The results show that in the low stress stage, the initial pores and fissures are compressed and the thermoelastic effect is insignificant. At the same time, the AE events are active, but most of the events are released with low energy. Then, the surface of the specimen shows stratified displacement phenomenon in the vertical direction. In the following stage, the thermoelastic effect is significant, and the average temperature of specimens shows a linear correlation with stress, whereas the AE is relatively inactive, and vertical surface deformation shows further homogenization and saliency. Because of the top and bottom constraints, the horizontal displacement field shows axis symmetrical distribution of double half-ellipse like a drum. During the yielding phase and the rupture moment, the average temperature rises obviously because of the heat from the friction of the rupture surface, and the temperature field also appears the phenomenon of differentiation; in the meantime, a large amount of AE events occur and the proportion of high energy events increases; further, the deformation field is significantly gathered near the ruptured position. Finally, the time sequence of the multiple physical parameters (AE parameters, average temperature, temperature fields, horizontal and vertical displacement fields) is summarized, which can be a reference for the stress state and failure analysis.