Thermal Stress Coupling Research Articles

Thermo-mechanical coupling characteristics of the shearer’s guiding shoe during the friction

The reliability and longevity of the guiding shoe are crucial for the proper functioning of coal mining machines. The heavy wear of the sliding surface under thermal stress coupling is the primary factor influencing the service life of the guiding shoe. To reveal the heat flow distribution patterns and the thermo-stress coupling mechanisms of the guiding surface, a thermo-mechanical coupling model of the guiding shoe and the pin row is established. The transient thermodynamic behavior of the guiding shoe under different load and speed conditions is studied using the coupled temp-displacement analysis method in Abaqus. The results indicate that the overall temperature of the guiding shoe friction surface experiences a rapid increase during the initial running-in phase, followed by a progressively slower temperature increase over time. Temperature and stress concentration regions on the friction surface primarily localize at the corners of the shoe groove, and the distribution of temperature and stress shows a strong coupling. Furthermore, elevated traction speed and mechanical load exacerbate the thermo-elastic instability of the guiding shoe, consequently augmenting thermal stress on the friction surface. The increase in support load results in significant thermal shock on the lower area of the left side of the guiding shoe. The research provides a reference for exploring the fatigue failure and wear mechanisms of the guiding shoe while considering thermal effects.

Effect of Interface Defects on the Electric–Thermal–Stress Coupling Field Distribution of Cable Accessory Insulation

The combined insulation interface of a high-voltage cable and accessories is the weakest part of a cable system. In this paper, the parameters of the dielectric constant, thermal conductivity, and elastic modulus of cross-linked polyethylene (XLPE) and silicone rubber (SIR) are obtained experimentally. On this basis, the model of a specific type of 110 kV cable and prefabricated insulation joint is established. A simulation of the electric–thermal–stress coupling field in the presence of typical defects in the main insulation–inner semi-conductive (SEMI) shielding layer (XLPE/SEMI interface) and the main insulation–silicone rubber insulation layer (XLPE/SIR interface) is studied. The simulation results show that at the XLPE/SIR interface, the electric field distortion caused by bubble defects reached 20.17 kV/mm, and the temperature rose to 56.15 °C. The effect of air-gap defects on the interface is similar to that of bubble defects. In addition, the semi-conductive impurity defects induced an increase in temperature to 56.82 °C and an increase in stress to 0.32 MPa. At the XLPE/SEMI interface, the electric field distortion induced by bubble defects was 19.98 kV/mm, and the temperature rose to 61.72 °C. The electric field distortion caused by metallic and semi-conductive defects was 8.44 kV/mm and 8.64 kV/mm, respectively. This study serves as a reference for the fault analysis and the operation and maintenance of cable accessories.

Advanced Analysis of Structural Performance in Novel Steel-Plate Concrete Containment Structures

This paper investigates the structural performance of novel steel-plate concrete containment structures, focusing on third-generation nuclear power plants. To address the challenges of increased complexities and costs associated with double-layer containment designs, this study explores the potential of steel-plate concrete structures to enhance safety, economic efficiency, and construction simplicity. The steel-plate concrete structure, characterized by its core concrete and dual steel plates, shows superior compressive strength, bending resistance, and elastoplasticity. Extensive numerical analyses, including finite element modeling and thermal-stress coupling, were conducted under various load conditions. Under structural integrity test conditions, the maximum radial displacement observed was 24.59 mm. Under design basis conditions, the maximum radial displacement was 47.61 mm; under severe accident conditions, it was 53.83 mm. The ultimate bearing capacity was 0.91 MPa, 2.17 times the design pressure. This study concludes that the steel-plate concrete containment structure maintains a high safety margin under all tested conditions, with stress and strain well within acceptable limits. It can effectively serve as a robust barrier against radioactive leakage and malicious impacts, providing a viable alternative to conventional containment designs.

Experimental and numerical investigations of post-fire behaviour of circular steel tube confined steel-reinforced concrete columns under eccentric loading

Experimental and numerical analysis were conducted to investigate the post-fire behaviour of circular steel tube confined steel reinforced concrete (STCSRC) columns. A total of fifteen circular STCSRC columns, including five stub specimens and ten slender specimens, were tested under eccentric loading after heating following the ISO-834 standard fire curve. The test findings, such as cross-sectional temperature, failure modes, column deformation, residual load-bearing capacity, strains of steel tubes, etc., were all discussed in detail. A sequential thermal-stress coupling finite element (FE) model, including a heat transfer FE model and a mechanical FE model, was then developed using ABAQUS software and verified using the test results. To obtain further numerical data over a wide range of parameters, a parametric analysis was carried out using the established FE models. A simplified calculation method was presented to estimate the residual load-bearing capability of circular STCSRC columns subjected to eccentrical compression after ISO-834 fire exposure.

Localized Phonon Transport Study of GaN/SiO2 Core/shell Nanowires under Thermal-Stress Coupling.

In order to comprehensively explore the intricate mechanisms of thermo-mechanical interactions, this study employs the molecular dynamics method to investigate the influence of heat flux density, shell thickness and length, as well as stress on the radial interface phonon transport in GaN/SiO2 core/shell nanowire. Additionally, the surface eigenmode decomposition method is employed to analyze the interface phonon dispersion curves. The investigation reveals that with increasing heat flux density, internal thermal stresses intensify, leading to a complex distribution of thermal stresses within the system. Under the influence of thermal stress, the nonlinear acoustic properties interact with phonon scattering, resulting in the pronounced localization of interface phonons. Compressive stress causes an upshift in low-frequency phonons, while tensile stress induces a downward shift in the high-frequency optical branches at the interface. The localized phonon vibrations at the SiO2/GaN interface under nonuniform stress are identified as the primary cause for the abundant presence of nondispersive phonon modes at the radial interface. By elucidating the subtle interplay between lattice vibrations and stress fields, this study offers a novel and profound understanding of thermo-mechanical coupling effects, thereby providing innovative theoretical foundations for the design and performance management of thermoelectric devices.

Failure mechanism and control method of cement sheath sealing integrity under alternating thermal-stress coupling in geothermal wells

In geothermal wells, exposure to extreme conditions of alternating temperature-pressure coupling (T-P-C) may lead to repeated expansion and contraction of the casing and cement sheath. This can degrade the cement sheath sealing integrity, resulting in continuous annular pressure. Consequently, an elastic-plastic mechanical model of the casing-cement sheath-formation (C–S–F) system under T-P-C was established based on thermodynamic theory and elastic-plastic theory with consideration of additional heating strain and thermal load, and it is solved by global search in MATLAB. The elastic-plastic mechanical behavior and development of interfacial contact stress are investigated under four typical working conditions. The failure mechanisms include interfacial debonding and micro-annulus formation between the casing and cement sheath under strong alternating temperatures (SAT). Cycling of temperature and accumulated plastic strain caused by the cement sheath entering plasticity are the major causes of interfacial stress inversion, which leads to interfacial debonding during temperature unloading. The influences of the mechanical and thermodynamic parameters of the cement sheath on its sealing integrity are analyzed. Based on this, an integrity control method is proposed, which comprises a cement slurry system and considers cement mechanical and thermodynamic parameters and environmental conditions. The results provide an important reference for the optimal design of cement slurry systems and for preventing cement sheath integrity failures due to SAT.

Study on the thermal-stress coupling simulation and surface friction of mechanical seal for water pump

In view of the problems that the mechanical seal for the water pump is prone to deformation, friction and wear, and loss of sealing performance in the process of use, taking the temperature change of end surface as the research entry point, the temperature distribution, stress and strain diagram of rotating ring, and stationary ring are obtained by thermal-stress coupling simulation. The temperature change of stationary ring is studied by the experiments, and the friction state of end surface of rotating ring and stationary ring are observed. The results indicate that the test temperature of stationary ring is slightly lower than simulation temperature, which is related to the thermocouple fixed on the side of the stationary ring for temperature measurement. In addition, comparing the micro morphology of end surface of rotating ring before and after the experiment, it is found that there is significant plastic deformation on the inner diameter of rotating ring, which is related to the stress generated by the thermal-mechanical coupling of inner diameter of rotating ring exceeding the material limit, consistent with the simulation results.

Thermal stress coupling mechanism during nanosecond impulse delay for the synergistic study of continuous-nanosecond combined laser removal of the rubber layer on a concrete surface.

Based on the principle of laser ablation and elastic vibration effect, a model of continuous nanosecond combined laser removal of rubber marks on a concrete surface was established. The model can explain the evolution of temperature, stress, and removal depth on time and laser energy density during laser cleaning. The results show that the theoretical adsorption force between the rubber layer and the concrete base is approximately 3.88×10-9 N. The continuous laser cleaning threshold is 561.31J/c m 2. In the combined laser, the continuous laser is 534.41J/c m 2, and the nanosecond laser is 0.35J/c m 2. As the delay time between the 2ns laser beams increases, the maximum peak in the temperature curve gradually decreases. The optimal cleaning delay was obtained as Δ t=0.65S. The peak temperature at the characteristic position (0µm, 0µm) is 592.13K, which is lower than the vaporization temperature of the rubber layer. The thermal stress values generated at this characteristic position exceed the adsorption stress values, indicating that the elastic removal mechanism is the main removal mechanism at the junction between the rubber layer and the concrete substrate.

Design and Analysis of Automatic Heat Sealing Production Line for a Top Cover

To complete the automatic heat sealing and inspection of a battery top cover, a new automatic heat sealing production line is designed in this paper. The production line is used to seal the upper and lower plates of the top cover and to test the related functions. The main purpose of the research is to improve the automation of the sealing and testing for this product. According to the working conditions and requirements of the company, the structure of the entire automatic heat sealing production line was designed through SolidWorks, and the operating principle of the key components were analysed. ANSYS was applied to carry out static analysis and thermal stress coupling analysis on the key components of the gripping and translating mechanism in the device to verify the rationality of its structural design.

Thermal stress simulation and fatigue life of commercial vehicle disk brakes under emergency braking conditions

Commercial vehicle disk brakes operate at a high-temperature and in a heavy-load environment within the braking system. The primary cause of failure is the cracking of the brake disk. In order to study its fatigue damage and service life, a finite element model of disk brake fatigue life was established, and thermal stress coupling simulation analysis was carried out from a practical problem. Based on the temperature and stress fields of the brake disk under emergency braking conditions obtained from the simulation results, the effects of vehicle load, initial speed, temperature, and other factors on brake fatigue life are explored. The fatigue life of the hazardous node can be calculated using the Manson–Coffin model, and then the strain–life (ɛ–N) curve of the material can be fit at high temperature. The fatigue life of brake disks was predicted using the fatigue analysis software FE-SAFE and verified by testing. The results showed that the maximum stress on the surface of the disk brake was the same as the area of the minimum fatigue life, accurately analyzing the fatigue life of the region and predicting the location of fatigue cracks. The results of the research can provide a reference for the design of disk brake engineering and fatigue failure.

A co-optimization method of thermal-stress coupling 3D integrated system with through silicon via

A co-optimization method of thermal-stress coupling 3D integrated system with through silicon via

Efficient Thermal-Stress Coupling Design of Chiplet-Based System with Coaxial TSV Array.

In this research, an efficient thermal-stress coupling design method for a Chiplet-based system with a coaxial through silicon via (CTSV) array is developed by combining the support vector machine (SVM) model and particle swarm optimization algorithm with linear decreasing inertia weight (PSO-LDIW). The complex and irregular relationship between the structural parameters and critical indexes is analyzed by finite element simulation. According to the simulation data, the SVM model is adopted to characterize the relationship between structural parameters and critical indexes of the CTSV array. Based on the desired critical indexes of the CTSV array, the multi-objective evaluation function is established. Afterwards, the structural parameters of the CTSV array are optimized through the PSO-LDIW algorithm. Finally, the effectiveness of the developed method is verified by the finite element simulation. The simulated peak temperature, peak stress of the Chiplet-based system, and peak stress of the copper column (306.16 K, 28.48 MPa, and 25.76 MPa) well agree with the desired targets (310 K, 30 MPa, and 25 MPa). Therefore, the developed thermal-stress coupling design method can effectively design CTSV arrays for manufacturing high-performance interconnect structures applied in Chiplet-based systems.

Simulation of RC Beams during Fire Events Using a Nonlinear Numerical Fully Coupled Thermal-Stress Analysis

The collapse and deterioration of infrastructures due to fire events are documented annually. These fire incidents result in multiple deaths and property loss. In this paper, a reliable and practical numerical methodology was introduced to facilitate the whole process of fire simulations and increase the practicality of performing comprehensive parametric studies in the future. These parametric studies are crucial for understanding the factors that affect thermal–structural responses and avoiding the high cost of destructive tests. The proposed algorithm comprises a fully nonlinear coupled thermal-stress analysis involving thermal and structural material nonlinearity and the thermal–structural response during a fire. A detailed numerical modeling analysis was performed with ABAQUS to achieve the proposed algorithm. The results of the proposed numerical methodology were validated against published experimental work. The experimental work includes a full-scale RC beam loaded with working loads and standard heating conditions to simulate real-life scenarios. The tested beam failed during the fire, and its fire resistance was recorded. The results demonstrated a good correlation with the experimental results in thermal and structural responses. Moreover, this paper presents the direct coupling technique (DCT) and the advantages of using DCT over the traditional sequential coupling technique (SCT).

The Development and Progress of Multi-Physics Simulation Design for TSV-Based 3D Integrated System

In order to meet the requirements of high performance, miniaturization, low cost, low power consumption and multi-function, three-dimensional (3D) integrated technology has gradually become a core technology. With the development of 3D integrated technology, it has been used in imaging sensors, optical integrated microsystems, inertial sensor microsystems, radio-frequency microsystems, biological microsystems and logic microsystems, etc. Through silicon via (TSV) is the core technology of a 3D integrated system, which can achieve vertical interconnection between stacked chips. In this paper, the development and progress of multi-physics simulation design for TSV-based 3D integrated systems are reviewed. Firstly, the electrical simulation design of TSV in a 3D integrated system is presented, including the lumped parameters model-based design and numerical computation model-based design. Secondly, the thermal simulation design of TSV in a 3D integrated system is presented based on the analytical model or numerical computation model. Thirdly, the multi-physics co-simulation design of TSV in a 3D integrated system is presented, including the thermal stress and electron thermal coupling simulation design. Finally, this paper is concluded, and the future perspectives of 3D integrated systems are presented, including the advanced integrated microsystems, the crossed and reconfigurable architecture design technology and the standardized and intelligent design technology.

Thermal-Stress Coupling Optimization for Coaxial through Silicon Via

In this paper, a thermal-stress coupling optimization strategy for coaxial through silicon via (TSV) is developed based on the finite element method (FEM), artificial neural network (ANN) model and particle swarm optimization (PSO) algorithm. In order to analyze the effect of design parameters on the thermal-stress distribution of coaxial TSV, the FEM simulations of coaxial TSV are conducted by COMSOL Multiphysics. The structure of coaxial TSV is symmetric. The mapping relationships between the design parameters and performance indexes are described by ANN models based on the simulation data of FEM. In addition, the multi-objective optimization function is formulated based on the desired performance indexes, and then the design parameters are optimized by the modified PSO algorithm. Based on the optimized design parameters, the effectiveness of the developed method is validated by FEM simulations. The simulated performance indexes agree well with the desired ones, which implies that the design parameters of coaxial TSV can be optimized to control the thermal-stress distribution. Therefore, the thermal-stress coupling optimization of coaxial TSV can achieve thermal-stress management to improve its reliability.

Modeling and Thermal Stress Coupling Optimization Design of TSV Inductors in On-Chip DC/DC Converters

Modeling and Thermal Stress Coupling Optimization Design of TSV Inductors in On-Chip DC/DC Converters

Comparative Analysis of Temperature Field and Stress Field of TC4 Ti-tanium Alloy Joint Between CMT and MIG Welding

A model was used for the cold metal transfer (CMT) welding based on the volume heat flux distribution of double ellipsoids loaded with time intervals. The temperature field and stress field of TC4 titanium alloy were numerically simulated by ANSYS software. The distribution laws of temperature, residual stress and post-weld deformation during CMT and MIG welding were studied and compared. It was found that the maximum temperature of the molten pool in CMT welding was fluctuating and rising during the loading process, while the temperature of the molten pool in MIG welding was rising smoothly and the maximum temperature was higher than that in CMT welding. The welding stress field was analyzed by thermal-stress coupling analysis. The stress distribution simulated based on the MIG welding heat source was similar to CMT welding, but the maximum von Mises stress was greater than that of CMT welding. Due to the cooling shrinkage, both of them would produce angular deformation after welding. And the maximum angular deformation simulated based on the MIG welding heat source was greater than that of CMT welding. It was proved by welding simulation that CMT welding could reduce welding heat input and residual stress and deformation after welding.

Effect mechanism of nitrogen injection into fire-sealed-zone on residual-coal re-ignition under stress in goaf

Coal is the one of foundations of energy and economic structure in China, while the unsealing of coal mine fires would cause a great risk of coal re-ignition. In order to explore the influence of pressure-bearing state on the re-ignition characteristics for residual coal, the uniaxial compression equipped with a temperature-programmed device was built. The scanning electron microscope, synchronous thermal analyzer and Fourier transform infrared absorption spectrometer was applied to investigate the microscopic structure and thermal effect of the coal samples. Moreover, the microscopic effect of uniaxial stress on coal re-ignition is revealed, and the re-ignition mechanism is also obtained. As the uniaxial stress increasing, the number, depth and length of the fractures of the pre-treated coal increases. The application of uniaxial stress causes the thermal conductivity to change periodically, enhances the inhibition of injecting nitrogen on heat transfer and prolonges the duration of oxidation exothermic. The content of oxygen-containing functional groups has a high correlation with apparent activation energy, and coal samples at 6 MPa is more probability to re-ignite while the fire zone is unsealed. Uniaxial stress could control the re-ignition mechanism by changing the structure of fractures and pores. The side chains and functional groups of coal structure are easier to be broken by thermal-stress coupling. The higher the ·OH content, the more difficult coal samples would be re-ignited. The research results would lay a solid theoretical foundation for the safe unsealing of closed fire-areas underground, tighten the common bond between the actual industry and the experimental theory in closed fire-areas underground, and provide the theoretical guidance for coal re-ignition preventing.

Performance of Concrete Structure after Fire Disaster Based on Thermal Stress Coupling Field Analysis

Concrete is a kind of non-combustible material, but its mechanical properties are quite sensitive to temperature, once the temperature exceeds the limit temperature of steel and concrete, the structure of the building will be broken, therefore it’s an urgent task to study the fire resistance, bearing capacity and stability of the concrete structure after fire disaster, and to respond to these questions, this paper studied the performance of concrete structure after fire disaster based on thermal stress coupling field analysis. At first, this paper gave the method for collecting displacement changes of each surface of concrete structure under high temperature during the experiment, and analyzed the thermal expansion strain of the concrete under thermal stress coupling effect. Then, to investigate the changes in the stability of concrete structure under high temperature, this paper simulated the thermal stress coupling of concrete structure after fire. After that, parameters of the concrete structure under high temperature were selected to further simulate the fire disaster temperature field of the concrete structure under high temperature and construct the corresponding heat conduction differential equations of the structure. At last, this paper analyzed the experimental results, proposed conclusions, and verified the effectiveness of the proposed parameter calculation method.

Identification of Friction Behavior Variation in the Minor Flank of Square Shoulder Milling Cutters under Vibration

In the milling process, the friction and wear of the tooth minor flank of the square shoulder milling cutter directly affects the machined surface quality and the cutter’s life. The friction of the minor flank of the cutter tooth presents a nonlinear distribution, and its variation cannot be revealed by using a single parameter. It is difficult to identify the dynamic characteristics of the friction of the minor flank of the cutter tooth. In this work, the friction velocity model for the cutter tooth minor flank was developed by using the relative motion relationship between the flank area element and the workpiece transition surface. In accordance with the atomic excitation theory developed under the potential energy field at the friction interface of the cutter, the model for friction energy consumption under the friction velocity and thermal-stress coupling field on the minor flank of the cutter tooth was developed. Based on the mechanism of the interfacial atomic thermal vibration, the model for the friction coefficient under thermal-stress mechanical coupling was developed. Using the instantaneous friction coefficient and normal stress, the instantaneous friction distribution function of the flank was obtained. Finally, an identification method for the friction dynamic characteristics of the shoulder milling cutter tooth flank under vibration was proposed and verified by experiments.