Search Results (21)

On-site multi-pass welding in building steel structures often induces transverse shrinkage, affecting assembly accuracy and final geometry. Pass-by-pass thermo-elasto-plastic simulation can capture the welding process but is computationally expensive for large steel components. This study proposes an efficient framework for predicting welding-induced transverse shrinkage in H-shaped steel beams by integrating merged weld-pass modeling, a shrinkage function model, and an equivalent indirect action method. A Q355B single-sided V-groove butt-welded plate was simulated to compare the original weld-pass model with three merged schemes. The balanced three-pass scheme preserved the main mechanical response while reducing computation time from 18.863 h to 5.528 h. Based on flat-position and vertical-position plate-welding simulations, a layered shrinkage function model was developed using a plate baseline term and a geometric coupling correction term, with LOOCV RMSE, MAE, and maximum absolute error values of 0.2855 mm, 0.2424 mm, and 0.5123 mm, respectively. The predicted shrinkage was then converted into an equivalent temperature load. The equivalent indirect action method achieved an MAE of 0.1883 mm, RMSE of 0.2713 mm, MAPE of 9.2685%, Pearson coefficient of 0.9730, and R² of 0.9042. This framework supports rapid transverse-shrinkage prediction and construction accuracy control for site-welded H-shaped steel beams. Full article

As transmission systems evolve toward lightweight design, gear webs are becoming thinner and more sensitive to deformation caused by the coupled action of heat-treatment residual stress, finish-turning thermo-mechanical loading, and clamping constraints. Existing studies mainly treat the initial residual stress or the machining-induced residual stress separately and often simplify the clamping boundary as an ideal fixed constraint. To overcome these limitations, this study proposes an initial-field-driven prediction framework for aerospace thin-web gears. The post-heat-treatment residual stress/strain field is reconstructed using the eigenstrain reconstruction method using measured residual stress and deformation data and is then introduced into the ABAQUS finish-turning model as the actual initial state. A three-jaw-chuck boundary consistent with the experiment and a progressive element birth–death strategy driven by the measured cutting force and temperature are used to describe material removal. In addition, a laser displacement sensor on-machine measurement (LOMM) method is developed for initial pose correction, deformation monitoring, and clamping-force interval optimization. The predicted final residual stress (FRS) distribution and machining deformation agree with the experimental measurements, with errors generally below 10%. The optimized clamping-force interval of 1350–1650 N provides a balance between cutting stability and deformation suppression. This work clarifies the coupled roles of the initial heat-treatment state and clamping constraints in thin-web gear finish turning and provides a reproducible modeling route for FRS and deformation prediction. Full article

In 3D integrated circuits, a placement decision that looks acceptable from a 2D wirelength view can still create a local thermal or stress problem after stacking. This issue becomes more visible as the number of tiers and the density of vertical interconnects increase. We propose ThermIC, a placement framework that brings thermal and mechanical risk estimates into the placement loop rather than treating them only as post-layout checks. The novelty of ThermIC does not lie in treating graph neural networks, reinforcement learning, uncertainty-aware learning, or physics-informed regularization as individually new techniques. Instead, ThermIC contributes a placement-time coupling mechanism in which physically typed graph propagation, dense multi-constraint risk prediction, and action-level reinforcement learning feedback are jointly organized for stacked 3D-IC placement. ThermIC uses a heterogeneous graph encoder to carry thermal, stress, timing, and congestion information through the netlist; a constraint head to estimate local hotspot, stress-risk, timing-violation, and congestion probabilities; and a sequential placement policy trained with physics-informed penalties. We evaluate the method on ThermIC-Bench, a simulated corpus with more than 30,000 finite-element samples from 18 heterogeneous 3D-IC designs with 4–8 tiers. Because the present study does not include proprietary industrial circuits, silicon measurements, or a tape-out case, the experimental results are interpreted as simulation-based benchmark evidence rather than final industrial qualification. ThermIC connects the heat-kernel branch to the discretized heat-conduction equation and the stress-filter branch to linear thermo-elastic equilibrium, providing a mechanism-level basis for physical interpretability. The analysis distinguishes offline simulation/training cost from online deployment cost and reports complexity, runtime, and memory scaling for practical large-scale use. Under joint DRC, thermo-mechanical stress, and thermally coupled timing checks, ThermIC obtains an $82.1\%$ physical verification pass rate. The peak-temperature error is $3.1$ °C, the hotspot localization IoU is 0.89, and the number of placement-closure iterations is reduced by $3.7\times$ relative to the heuristic baseline. Together, these benchmark results indicate that early, differentiable multi-physics feedback can make 3D placement less dependent on late correction cycles. Full article

An analytical model is developed to investigate the bending performance of composite I-beams with corrugated steel web (CSW) under thermo-mechanical coupling. The CSW is idealized as an equivalent orthotropic plate according to the principle of stiffness equivalence and heat conservation. The steady-state temperature field of the composite I-beam cross-section is obtained using the finite difference method. Based on thermoelastic theory, analytical solutions for the stresses and displacements of the composite beam subjected to thermo-mechanical loads are derived by the eigenvalue method and transfer matrix method. The results obtained in this study are compared with available experimental results from a steel–concrete composite bridge deck, ABAQUS (version: 2023) finite element simulations, and the temperature distributions specified by JTG D60-2015, AASHTO 2017 and DIN 101. In addition, the superposition principle for thermo-mechanical conditions is verified by the analytical forms of stress and displacement solutions. And the research results show that increasing interfacial stiffness restrains the relative thermal deformation between the concrete slab and the steel I-beam, thereby increasing temperature-induced stresses and deformations. Finally, a partial thermal insulation method is proposed to mitigate temperature gradients, thermal stresses and upward thermal deformation, thereby improving the service performance of the composite beam under thermal actions. Full article

Reaction-bonded silicon carbide (RB-SiC) is the preferred material for space optical systems because of its low density and high specific stiffness. However, its hardness and multi-component properties lead to low efficiency and pit defects during the polishing process, making the fabrication of RB-SiC a significant challenge. This study proposes a high-efficiency and low-defect fabrication method for RB-SiC using center-inlet computer-controlled polishing (CCP). We first investigated the polishing efficiency and surface quality achieved with center-inlet and non-center-inlet liquids. The results show that the defect density under non-center-inlet conditions was positively correlated with process parameters, while fewer defects and higher efficiency could be achieved under center-inlet conditions. Additionally, the efficient removal and defect suppression mechanisms under the center-inlet condition were revealed based on machining force, heat, and defect characterization. Under center-inlet conditions, the friction coefficient is larger and stable, resulting in high removal efficiency. The macro–micro coupled analysis results show that pit defects are generated through the combined action of force and heat, which leads to the thermo-mechanical degradation and shedding of SiC particles due to the temperature increase in the machining zone. The results demonstrate that center-inlet CCP not only ensures sufficient abrasion at the polishing interface to achieve high removal efficiency but also significantly suppresses the processing heat, thereby resulting in a low-defect surface. Full article

This paper reviews constitutive models used to predict concrete spalling under elevated temperatures, with emphasis on fire exposure and concrete linings in deep geological repositories for spent fuel and nuclear waste. The review synthesizes (1) how material composition (ordinary Portland cement concrete, geopolymer concrete, and fiber-reinforced systems using polypropylene and steel fibers) affects spalling resistance; (2) how coupled environmental and mechanical actions (temperature, moisture, stress state, chloride ingress, and radiation) drive damage initiation and spalling; and (3) how constituent-scale characteristics (microstructure, porosity, permeability, elastic modulus, and water content) govern thermal–hydro–mechanical–chemical (THMC) transport and damage evolution. We compare major constitutive modeling frameworks, including plasticity–damage models (e.g., concrete damage plasticity), statistical damage approaches, and fully coupled THM/THMC formulations, and highlight how key parameters (e.g., water-to-binder ratio, temperature-driven pore-pressure gradients, and crack evolution laws) control predicted spalling onset, depth, and timing. Several overarching challenges emerge: lack of standardized experimental protocols for spalling tests and assessments, which limits cross-study benchmarking; continued debate on whether spalling is dominated by pore pressure, thermo-mechanical stress, or their interaction; limited integration of multiscale and constituent-level material characteristics; and high data and computational demands associated with advanced multi-physics models. The paper concludes with targeted research directions to improve model calibration, validation, and performance-based design of concrete systems for high-temperature and repository applications. Full article

To optimize the aerodynamic performance of the aircraft across its entire cross-section, wing shape control must be maintained based on flight operating conditions. A high-temperature flexible textile composite, which is the key to achieving the deformation of an aircraft wing, is urgently required in the deformable structure of high-speed aircraft. In this work, a novel type of flexible textile composite with enhanced temperature resistance was fabricated by plain-woven carbon fibers coated with silicone rubber. The material testing was carried out in a wind tunnel to simulate both the harsh temperature field distribution and the mechanical loads caused by aerodynamic forces under the flight profile. For the first time, temperatures exceeding 1000 °C were attained on the windward side of an aircraft wing with a peak recorded temperature of 1600 °C. The failure mechanisms of the flexible composites are revealed, and the thermal stability of the composites is evaluated. The results show that the significant tensile anisotropy in the flexible composites is along different off-axis angles, and the failure modes also change with the off-axis angle. The material does not show significant high-temperature oxidation ablation under thermo-mechanical coupling. This work reveals that under the triple action of such high temperatures, stress caused by wing surface tensioning, and the mechanical load caused by aerodynamic forces, the failure mechanism of the flexible textile composite is dominated by the mechanical load at high temperatures rather than by thermal instability, as is conventionally claimed. Full article

This work introduces a path-dependent energy Lagrangian for irreversible thermomechanics that embeds heat and entropy accounting directly into the action. The formulation requires neither Lagrange multipliers nor Rayleigh potentials. An explicit $\theta s$ term enforces Helmholtz conjugacy and positive heat capacity; writing heat as a divergence produces the natural flux; nonnegative dissipative productions are collected in a single modular term; and a history integral supplies an upper-limit variation that converts instantaneous power into entropy production. Stationarity yields the standard field equations together with a global entropy balance and a channel-wise power identity by placing each production once in entropy and once, with opposite sign, in its own channel. Classical closures—including Fourier and non-Fourier heat conduction, diffusion, and viscous mechanics—arise as special cases of the same functional. Compact examples show how the framework provides a unified action, a single entropy audit, and consistent positive production across coupled dissipative mechanisms. Full article

This paper reports an investigation of the thermomechanical behavior at the interface of GFRP/Al composite stacks when the stacking arrangement varies. A temperature-coupled damage approach was developed to simulate thermal energy transfer and damage propagation at metallic-to-composite interface. The proposed model was then implemented into ABAQUS/Explicit finite element code using user-defined subroutine VUMAT finely imbricated with VDFLUX. Unlike to previous models, oblique cutting configuration (OCC) involving double-inclination of the tool was proposed to simulate finely the material removal process owing to drill action. Drilling trials involving the cutting speed and the stacking arrangement were conducted to support the proposed approach. The predictions revealed that increasing the spindle speed significantly impacts the temperature distribution and subsurface thermal damage. An exponential temperature law was derived for predicting temperature variation with the cutting speed and identifying thermal saturation at the interface. The sensitivity of the composite behavior to the stacking arrangement (GFRP → Al vs. Al → GFRP) was well highlighted. The results indicated that attacking the structure from the GFRP side results in higher interfacial temperatures due to GFRP’s lower thermal conductivity. These findings contribute to understanding the heat-affected zone in GFRP, and, hence, provide guidance to minimize thermal damage in industrial drilling of the hybrid stacks. Full article

A cryogenic hose is used to transport liquefied natural gas at sea, where flexible fittings are sealed by corrugated lining and end flange welding. However, the extreme cryogenic temperatures of the conveyed fluid introduce substantial challenges to the integrity of the fitting seals’ structure during the LNG transfer process. In order to study the sealing performance of the fitting under LNG conveying conditions, this paper was based on the general finite element software ABAQUS 6.11 to carry out a thermo-mechanical coupling analysis of the end sealing stress. This paper also established a sealing performance analysis model of the corrugated fitting welding area under the fitting action of LNG load and internal pressure load. A sensitivity analysis was conducted on the influence of weld clearance, blunt edge size, and weld residual height on the weld stress of a fitting ring. The results show that, under the combined action of the medium internal pressure and cryogenic load, the size design of the weld area significantly affects the sealing performance of the fitting, among which the equivalent force of the weld clearance butt sealing area has the greatest impact. Moreover, it was found that a pressure of 5 MPa was 2 mm when the weld clearance was 2 mm, and the average stress at the weld was 53.68 MPa. Further, considering the synergistic influence of the blunt edge size, the weld clearance was 3 mm, the stress was minimal when the blunt side size was 4 mm, and the average stress was 17.42 MPa. These research results can serve as a reference for the design and analysis of the sealing structure of non-adhesive inner corrugated cryogenic hose fittings. Full article

Excessive thermal stress can cause the failure of a solid oxide fuel cell (SOFC), and an inhomogeneous temperature field is one of the reasons for thermal stress in the cell. In the present work, the bi-dimensional thermo-mechanical coupling models of SOFCs with different interface morphologies including planar and corrugated cells are proposed. The temperature distribution of two types of cells under the action of heat conduction is analyzed. Further, the inhomogeneous temperature field caused by gas flow is used as the thermal load to compare the thermal stress distribution of planar and corrugated cells. The influence of interface morphology on the temperature distribution, stress distribution and the contribution of the temperature gradient to stress distribution are investigated. This research provides a reference for reducing thermal stress and improving the stability of SOFC. Full article

In this paper, based on in situ synchrotron radiation SAXS technology, the effects of stress field, temperature field and thermo-mechanical coupling conditions on the evolution of residual stress are discussed, respectively. The results show that the continuous increase of the external load led to the increase of the residual stress perpendicular to the tensile direction of the 2A14 aluminum alloy, and when the external load closed to the yield strength, the change of the residual stress was no longer significant. Under the action of temperature, the residual stress of 2A14 aluminum alloy reduced after the process of heating–holding–cooling. Under the action of thermo-mechanical coupling, the recovery effect of aluminum alloy was triggered, the energy storage of deformation was released, the lattice strain was reduced and the residual stress introduced by external load was reduced. Full article

In this study, the mechanical responses of a functionally graded thick-walled tube simultaneously under magnetic, thermal and mechanical loads are studied. Based on the assumption that the volume fraction of each phase material is distributed as a power function, the Voigt method is used to obtain the stress–strain relationship of the functionally graded materials (FGMs). The influences of the relevant material parameters including volume fraction, thermal expansion coefficient, and Poisson’s ratio on the magneto-thermo-elastic theoretical solution are deeply studied and discussed. Furthermore, when some of the parameters are set as special values, the research results can be degenerated to two coupled loads which are consistent with the existing researches. The results of this paper provide theoretical support for the practical design and application of the FGM tube under the combined action of magnetic, thermal and mechanical loads. Full article

Thermal barrier coatings (TBCs) suffer from the thermo-chemo-mechanical coupling action of thermal shock and calcium–magnesium–alumina–silicate (CMAS) corrosion. However, the failure mechanism of TBCs under the synergistic effect of thermal shock and CMAS corrosion is still unclear due to a lack of an environmental simulator. Herein, an 8YSZ ceramic coating is deposited on a PtAl bond coating/DD419 nickel-based single crystal superalloy substrate using the electron beam physical vapor deposition (EB-PVD) method. The thermo-chemo-mechanical coupling effect of TBCs is achieved in a self-developed environmental simulator. The interaction of volume expansion induced by the phase transition of ZrO₂, structural degradation and thermal fatigue further increases the out-of-plane tensile stress and in-plane shear stress in the ceramic coating, which accelerates the initiation and propagation of surface vertical cracks and horizontal cracks. As multiple surface vertical cracks propagate to the interface and merge with interfacial cracks, the ceramic coating spalls from the substrate. Full article

The present work aims to enhance the use of agricultural byproducts for the production of bio-composites by melt extrusion. It is well known that in the production of such bio-composites, the weak point is the filler-matrix interface, for this reason the adhesion between a polylactic acid (PLA)/poly(butylene succinate)(PBSA) blend and rice and wheat bran platelets was enhanced by a treatment method applied on the fillers using a suitable beeswax. Moreover, the coupling action of beeswax and inorganic fillers (such as talc and calcium carbonate) were investigated to improve the thermo-mechanical properties of the final composites. Through rheological (MFI), morphological (SEM), thermal (TGA, DSC), mechanical (Tensile, Impact), thermomechanical (HDT) characterizations and the application of analytical models, the optimum among the tested formulations was then selected. Full article