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1
Hu, Chang Bin, Mu Lu Du, and Li Juan Wang. "Research of Built-In Temperature and Zero Stress Temperature of Cement Concrete Pavement at Early Ages." Advanced Materials Research 857 (December 2013): 248–55. http://dx.doi.org/10.4028/www.scientific.net/amr.857.248.
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Based on field tests and numerical simulation methods, distribution characteristics of early-age built-in temperature of cement concrete pavement constructed in different seasons and pouring time were analyzed firstly. Then considering effect of creep, characteristics of early-age zero stress temperature in cement concrete that built-in temperature of cement concrete pavement constructed in different seasons and pouring time has a great difference. The distributions of built-in temperature along the thickness present nonlinear obviously, and they have four typical types: concave and positive gradient type, concave negative gradient type, convex positive gradient type and convex negative gradient type. Zero stress temperature gradient shows prominently developing process compared with built-in temperature of slab at different ages by the effect of creep. Zero stress temperature of slab poured on am7:00 in summer firstly increase and then decline. Besides, the positive gradient change to negative gradient gradually, and the gradient of zero stress temperature trend to decrease. At last, it is recommended to calculate zero stress temperature of slab consideration of base temperature and the nonlinear distributions characteristics, and the combined effect of creep and age.
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Wang, Da, Benkun Tan, Xie Wang, and Zhenhao Zhang. "Experimental study and numerical simulation of temperature gradient effect for steel-concrete composite bridge deck." Measurement and Control 54, no. 5-6 (2021): 681–91. http://dx.doi.org/10.1177/00202940211007166.
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The temperature distribution of the bridge and its thermal effect has always been an important issue for researchers. To investigate the temperature distribution and thermal stress in the steel-concrete composite bridge deck, a 1:4 ratio temperature gradient effect experimental study was carried out in this paper. First, a set of experimental equipment for laboratory temperature gradient loading was designed based on the principle of temperature gradient caused by solar radiation, the temperature gradient obtained from the measurements were compared with the specifications and verified by the FE method. Next, the loading of the steel-concrete composite deck at different temperatures was performed. The thermal stress response and change trend of the simply supported and continuously constrained boundary conditions under different temperature loads were analyzed. The experimental results show that the vertical temperature of steel-concrete composite bridge deck is nonlinear, which is consistent with the temperature gradient trend of specifications. The vertical temperature gradient has a great influence on the steel-concrete composite bridge deck under different constraints, and the extreme stress of concrete slab and steel beam is almost linear with the temperature gradient. Finally, some suggestions for steel-concrete composite deck design were provided based on the research results.
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Zheng, Zhi Jun, Xiao Kai Wang, and Ji Lin Yu. "Mass Impact of Density-Graded Cellular Metals in a Temperature Field." Applied Mechanics and Materials 566 (June 2014): 599–604. http://dx.doi.org/10.4028/www.scientific.net/amm.566.599.
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We consider the problem of a density-graded cellular rod in a temperature gradient field axially subjected to a mass impact. Two-dimensional cell-based finite element models and one-dimensional shock models are employed to explore the mechanisms of deformation and wave propagation. The yield stress distribution in a cellular specimen depends on both the density gradient field and the temperature gradient field. The stress distribution and the yield stress distribution are analyzed. For the increasing yield stress along the impact direction, one shock front propagates from the proximal end to the distal end of the specimen. For the decreasing yield stress along the impact direction, two shock fronts propagate in opposite directions and the one close to the proximal end ceases at a particular time. The predicted stresses of the extended shock models are compared well with the numerical results.
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Zhao, Ya Ding, Xue Ying Li, and Hong Yang Liu. "Simulation and Analysis of the Thermal Stress in Concrete under Temperature Fluctuation Condition." Advanced Materials Research 168-170 (December 2010): 1957–60. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1957.
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The temperature field distribution and thermal stress distribution in concrete has been studied by finite elements method to establish the relationship between the thermal stress and the temperature in this paper. The results show that the maximum thermal gradient and the maximum thermal stress in the concrete appears on the direction of greater structural dimension, and the thermal stress value is positively correlated with thermal gradient or saying temperature difference and elastic modulus, and is negatively correlated with the water content and air content.
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Yao, Lei. "Influence of Cooling Rate on Crack Growth and Stress Distribution in Die Steel under Thermal Cycles." International Journal of Mechanical and Electrical Engineering 4, no. 2 (2024): 67–72. https://doi.org/10.62051/ijmee.v4n2.09.
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Die casting molds are prone to thermal fatigue under high-temperature and high-pressure cycles, which significantly affects their service life. In this study, a three-dimensional numerical simulation method is employed to analyze the temperature field, stress field, and crack development process of the mold under different cooling cycles. The results show that shorter cooling cycles (15s, 30s) lead to larger temperature gradients and stress concentrations within the mold, thereby accelerating crack initiation and propagation. In contrast, longer cooling cycles (70s) help to reduce the temperature gradient and stress fluctuations, which in turn slows down crack propagation and effectively extends the mold's service life.
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Gan, Yu-Feng, and Jiin-Yuh Jang. "Optimal Heat Transfer Coefficient Distributions during the Controlled Cooling Process of an H-Shape Steel Beam." Advances in Materials Science and Engineering 2017 (2017): 1–15. http://dx.doi.org/10.1155/2017/9873283.
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Three-dimensional thermal-mechanical models for the prediction of heat transfer coefficient distributions with different size beams are investigated. H300 × 300, H250 × 250, and H200 × 200 H-shape steel beams are investigated in a controlled cooling process to obtain the design requirements for maximum uniform temperature distributions and minimal residual stress after controlled cooling. An algorithm developed with the conjugated-gradient method is used to optimize the heat transfer coefficient distribution. In a comparison with the three group results, the numerical results indicate that, with the same model and under the same initial temperature (T=850°C) and final temperature (T=550±10°C), the heat transfer coefficients obtained with the conjugated-gradient method can produce more uniform temperature distribution and smaller residual web stress, with objective functions of the final average temperature Tave±ΔT and maximum temperature difference to minimum minΔTmax(x,y). The maximum temperature difference is decreased by 57°C, 74°C, and 75°C for Case 1, Case 2, and Case 3, respectively, the surface maximum temperature difference is decreased by 60~80°C for three cases, and the residual stress at the web can be reduced by 20~40 MPa for three cases.
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Yang, Guang, Wei Wang, Lan Yun Qin, and Xing Lang Wang. "Numerical Simulation Temperature Field of Laser Cladding Titanium Alloy." Applied Mechanics and Materials 117-119 (October 2011): 1633–37. http://dx.doi.org/10.4028/www.scientific.net/amm.117-119.1633.
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Abstract: In order to control the thermal stress of cladding, a numerical simulation of temperature field during multi-track & multi-layer laser metal deposition (LMD) process is developed with ABAQUS based on “element birth and death” technology of FEM. The dynamic variances of temperature field and stress field of forming process are calculated with the energy compensation of interaction between molten pool-powder. The temperature field, temperature gradient, thermal stress field and distribution of residual stress are obtained. The results indicate that although the nodes on different layers are activated at different time, their temperature variations are similar. The temperature gradients of samples are larger near the molten pool area and mainly along z-direction.
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Aniekan, Essienubong Ikpe Michael Okon Bassey. "Modelling and Simulation of Transient Thermal Stress Distribution across AISI 1018 Flat Plates at Variable Welding Temperature Regime." Journal of Materials Engineering, Structures and Computation 2, no. 3 (2023): 1–22. https://doi.org/10.5281/zenodo.8297860.
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<em>In recent times, failure in structural components has been attributed to a lack of improper understanding of material behaviour under welding temperature, during which thermally induced stresses are trapped (residual stress) within the weldment. This study investigated the effects of variable Tungsten Inert Gas (TIG) welding temperature across AISI 1018 flat plates concerning thermal stress distribution using experimental and Finite Element Method at welding temperatures ranging from 6800-9600<sup>o</sup>F. Thermally-induced stresses of 4244.373 and 4345.894 MPa were obtained from both FEM and Experimental process at a welding temperature of 680<sup>o</sup>F while the thermally induced stress values at a higher welding temperature of 9600<sup>o</sup>F for FEM and experimental process were obtained as 10786.858 and 12124.269 MPa. The study revealed a significant correlation established between the experimentally induced thermal stress distribution and the FEM-induced thermal stress distribution. Moreover, thermally induced stresses were observed to increase as the welding temperature also increased and vice versa. Hence, the FEM approach employed in the study can be adopted as a novel technique for modelling, prediction and control of welding temperature to prevent intense welding heat from translating into detrimental defects due to creep mechanism (thermal loading temperature on material geometry), which may result in untimely failure of component materials in welding-related applications. </em>
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Jameel, Adnan N., Nabeel K. Abid Al-Sahib, and Osama F. Abd Al Latteef. "RESIDUAL STRESS DISTRIBUTION FOR A SINGLE PASS WELD IN PIPE." Journal of Engineering 16, no. 01 (2010): 4618–30. http://dx.doi.org/10.31026/j.eng.2010.01.18.
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Heat input due to the welding of mild steel pipe causes a temperature gradient in the parent metal. After welding and temperature cooling down, residual stresses appear around welding zone which reduces the weld strength. Residual stresses are a result of the temperature gradient and the dependency of material properties on the temperature, such as yield strength, elasticity modulus, and thermal expansion coefficient.In this study, a typical flat joint of a single pass weld in a thin pipe was studied analytically and numerically. Analytical approach is performed by exploring a simple method to calculate the magnitude of residual stress in terms of the weld shrinkage behavior. Numerical analysis is performed by applying non-linear transient heat transfer analysis using welding parameters, such as heat generation, free or force convection with ambient, are performed using a general purpose FE package ANSYS 8.0 in order to obtain the temperature distribution in the welded parts. A non-linear thermal-elastic-plastic stress analysis is then performed using the same package to predict the stress fields during and after welding.
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Koizumi, M., and M. Niino. "Overview of FGM Research in Japan." MRS Bulletin 20, no. 1 (1995): 19–21. http://dx.doi.org/10.1557/s0883769400048867.
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Space planes require high-performance heat-resistant materials which can withstand ultrahigh temperatures and extremely large temperature gradients. To meet these needs, functionally gradient materials (FGMs) were proposed about 10 years ago in Japan.Figure 1 shows a conceptual diagram of functionally gradient materials, taking into account the relaxation of thermal stress. For the surface that contacts high-temperature gases at thousands of degrees, ceramics are used to provide adequate heat resistance. For the surface that provides cooling, metallic materials are used to furnish the necessary thermal conductivity and mechanical strength. In addition, the composition of these materials is formulated to provide optimum distribution of composition, structure, and porosity to effectively relax thermal stress.Since fiscal 1987, an R&D project entitled “Research on Fundamental Techniques to Develop Functionally Gradient Materials for Relaxation of Thermal Stress,” which aimed to develop ultra heat-resistant materials, had been carried out with special coordination funds from the Science and Technology Agency. The five-year project had two phases; Phase I was carried out from 1987 to 1989, and Phase II from 1990 to 1991.
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Lei, Xiao, Xutao Fan, Hanwan Jiang, Kunning Zhu, and Hanyu Zhan. "Temperature Field Boundary Conditions and Lateral Temperature Gradient Effect on a PC Box-Girder Bridge Based on Real-Time Solar Radiation and Spatial Temperature Monitoring." Sensors 20, no. 18 (2020): 5261. http://dx.doi.org/10.3390/s20185261.
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Climate change could impose great influence on infrastructures. Previous studies have shown that solar radiation is one of the most important factors causing the change in temperature distribution in bridges. The current temperature distribution models developed in the past are mainly based on the meteorological data from the nearest weather station, empirical formulas, or the testing data from model tests. In this study, a five-span continuous Prestressed-concrete box-girder bridge was instrumented with pyranometers, anemometers, strain gauges, displacement gauges, and temperature sensors on the top and bottom slabs and webs to measure the solar radiation, wind speeds, strain, displacement, and surface temperatures, respectively. The continuously monitoring data between May 2019 and May 2020 was used to study the temperature distributions caused by solar radiation. A maximum positive lateral temperature gradient prediction model has been developed based on the solar radiation data analysis. Then, the solar radiation boundary condition obtained from the monitoring data and the lateral temperature gradient prediction model were utilized to compute the tensile stresses in the longitudinal and transverse directions. It was demonstrated in this study that the tensile stress caused by the lateral temperature gradient was so significant that it cannot be ignored in structural design.
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Ulbricht, Alexander, Simon J. Altenburg, Maximilian Sprengel, et al. "Separation of the Formation Mechanisms of Residual Stresses in LPBF 316L." Metals 10, no. 9 (2020): 1234. http://dx.doi.org/10.3390/met10091234.
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Rapid cooling rates and steep temperature gradients are characteristic of additively manufactured parts and important factors for the residual stress formation. This study examined the influence of heat accumulation on the distribution of residual stress in two prisms produced by Laser Powder Bed Fusion (LPBF) of austenitic stainless steel 316L. The layers of the prisms were exposed using two different border fill scan strategies: one scanned from the centre to the perimeter and the other from the perimeter to the centre. The goal was to reveal the effect of different heat inputs on samples featuring the same solidification shrinkage. Residual stress was characterised in one plane perpendicular to the building direction at the mid height using Neutron and Lab X-ray diffraction. Thermography data obtained during the build process were analysed in order to correlate the cooling rates and apparent surface temperatures with the residual stress results. Optical microscopy and micro computed tomography were used to correlate defect populations with the residual stress distribution. The two scanning strategies led to residual stress distributions that were typical for additively manufactured components: compressive stresses in the bulk and tensile stresses at the surface. However, due to the different heat accumulation, the maximum residual stress levels differed. We concluded that solidification shrinkage plays a major role in determining the shape of the residual stress distribution, while the temperature gradient mechanism appears to determine the magnitude of peak residual stresses.
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Wang, Q., W. L. Gu, D. L. Sun, X. L. Han, and M. Y. Xue. "Numerical Simulation of Gradient Heat Treatment Process of Cylinder Welding Component of 30Si2MnCrMoV Steel." Advanced Materials Research 664 (February 2013): 990–95. http://dx.doi.org/10.4028/www.scientific.net/amr.664.990.
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The finite element analysis method was applied to simulate the gradient field heat treatment process of a cylinder welding component of 30Si2MnCrMoV steel by software ANSYS. In the heat treatment process，the distribution of temperature field, the variation curve of residual stress with time，the distribution of residual stress along the axial direction of cylinder, and the axial and radial deformation of the specimen were calculated and the influences of partial heating area on the distribution of temperature and residual stress were analyzed. The calculating results show that the temperature in the weld metal zone and heat affected zone of welding specimens may exceed the phase transformation points during the gradient heat temperature. The residual stress and the radial deformation in the weld metal zone were greater than those in the matrix zone. The final deformation of specimen was along the axial direction. With the increase of partial heating area, the phase transformation area was increased and the residual stress was reduced effectively.
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Qin, Qin, Weizhuang Li, Wenrui Wang, Dongyue Li, and Lu Xie. "Effect of Temperature Gradient and Cooling Rate on the Solidification of Iron: A Molecular Dynamics Study." Materials 17, no. 24 (2024): 6051. https://doi.org/10.3390/ma17246051.
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In this study, molecular dynamics (MD) simulations were employed to compare the effects of different solidification conditions on the solidification behaviour, stress distribution, and degree of crystallization of iron. The results indicate significant differences in nucleation and microstructural evolution between the two solidification methods. In the homogeneous temperature field, the solidification of iron is characterized by instantaneous nucleation. The BCC phase surged at 1431 K followed by the phenomenon of latent heat of crystallization. As the temperature continued to decrease, the percentage of the BCC phase continued to increase steadily. Eventually, the atoms aggregated to form a crystal nucleus and grow outward to form polycrystalline structures. During gradient solidification, continuous nucleation of iron leads to a slow increase in the BCC phase. From the initial stage of solidification, the solid–liquid interface moves in the direction of higher temperature and is accompanied by a higher stress distribution. Furthermore, increasing the temperature gradient, particularly the cooling rate, accelerates the transformation efficiency of iron in the gradient solidification process. In addition, increasing the cooling rate or temperature gradient reduces the residual stress and crystallinity of the solidified microstructure. It is worth noting that an increased temperature gradient or cooling rate will produce higher residual stress and uneven microstructure in the boundary region. This study provides an atomic-level understanding of the improvement in the solidification performance of iron.
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Xie, Jiamiao, Jingyang Li, Wenqian Hao, and Fenghui Wang. "Influence of Interface Morphology on the Thermal Stress Distribution of SOFC under Inhomogeneous Temperature Field." Energies 16, no. 21 (2023): 7349. http://dx.doi.org/10.3390/en16217349.
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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.
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Yang, Lin. "Effect of Temperature and Pressure of Supercritical CO2 on Dewatering, Shrinkage and Stresses of Eucalyptus Wood." Applied Sciences 11, no. 18 (2021): 8730. http://dx.doi.org/10.3390/app11188730.
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Supercritical CO2 (SuCO2) dewatering can mitigate capillary tension and reduce wood collapse. In this study, Eucalyptus urophylla × E. grandis specimens were dewatered by SuCO2 at temperatures of 35, 40 and 55 °C, in pressures of 10 and 30 MPa, respectively, for 1h. Effects of temperature and pressure on dewatering rate, moisture content (MC) distribution and gradient, shrinkage and residual stress of wood after dewatering were investigated. The results indicate that the SuCO2 dewatering rate is much faster than that of conventional kiln drying (CKD). The dewatering rate increases with increasing of temperature and pressure; however, pressure has a significant influence, especially for the high-temperature dewatering process; the MC distribution after 1h dewatering is uneven and MC gradients decrease with reducing of mean final MC of wood. MC gradients along radial direction are much smaller than that in tangential direction; collapse of wood significantly reduces after dewatering due to SuCO2 decreasing the capillary tension, and residual stress of wood during dewatering is mainly caused by pressure of SuCO2, which decreases with increasing temperature. SuCO2 dewatering has great potential advantages in water-removal of wood prone to collapse or deformation.
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Bajwoluk, A., and P. Gutowski. "The Effect of Cooling Agent on Stress and Deformation of Charge-loaded Cast Pallets." Archives of Foundry Engineering 17, no. 4 (2017): 13–18. http://dx.doi.org/10.1515/afe-2017-0123.
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Abstract The results of research on the effect of the type of cooling agent used during heat treatment and thermal-chemical treatment on the formation of temperature gradient and stress-deformation distribution in cast pallets, which are part of furnace accessories used in this treatment, are disclosed. During operation, pallets are exposed to the effect of the same conditions as the charge they are carrying. Cyclic thermal loads are the main cause of excessive deformations or cracks, which after some time of the cast pallet operation result in its withdrawal due to damage. One of the major causes of this damage are stresses formed under the effect of temperature gradient in the unevenly cooled pallet construction. Studies focused on the analysis of heat flow in a charge-loaded pallet, cooled by various cooling agents characterized by different heat transfer coefficients and temperature. Based on the obtained temperature distribution, the stress distribution and the resulting deformation were examined. The results enabled drawing relevant conclusions about the effect of cooling conditions on stresses formed in the direction of the largest temperature gradient.
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Mohammadkamal, Helia, and Fabrizia Caiazzo. "Numerical Study to Analyze the Influence of Process Parameters on Temperature and Stress Field in Powder Bed Fusion of Ti-6Al-4V." Materials 18, no. 2 (2025): 368. https://doi.org/10.3390/ma18020368.
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This paper presents a comprehensive numerical investigation to simulate heat transfer and residual stress formation of Ti-6Al-4V alloy during the Laser Powder Bed Fusion process, using a finite element model (FEM). The FEM was developed with a focus on the effects of key process parameters, including laser scanning velocity, laser power, hatch space, and scanning pattern in single-layer scanning. The model was validated against experimental data, demonstrating good agreement in terms of temperature profiles and melt pool dimensions. The study elucidates the significant impact of process parameters on thermal gradients, melt pool characteristics, and residual stress distribution. An increase in laser velocity, from 600 mm/s to 1500 mm/s, resulted in a smaller melt pool area and faster cooling rate. Similarly, the magnitude of residual stress initially decreased and subsequently increased with increasing laser velocity. Higher laser power led to an increase in melt pool size, maximum temperature, and thermal residual stress. Hatch spacing also exhibited an inverse relationship with thermal gradient and residual stress, as maximum residual stress decreased by about 30% by increasing the hatch space from 25 µm to 75 µm. The laser scanning pattern also influenced the thermal gradient and residual stress distribution after the cooling stage.
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Kong, Yuan, Wei Jun Liu, and Yue Chao Wang. "Numerical Simulation of Temperature Field of Direct Laser Metal Deposition Shaping Process of Titanium Alloys." Advanced Materials Research 295-297 (July 2011): 2112–19. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.2112.
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In order to control the thermal stress of forming process, based on “element birth and death” technology of finite element method, a numerical simulation of three-dimensional temperature field and stress field during multi-track & multi-layer laser metal deposition shaping(LMDS) process is developed with ANSYS parametric design language (APDL). The dynamic variances of temperature field and stress field of forming process are calculated with the energy compensation of interaction between molten pool-powder and laser-powder. The temperature field, temperature gradient, thermal stress field and distribution of residual stress are obtained. The results indicate that although the nodes on different layers are activated at different time, their temperature variations are similar. The temperature gradients of samples are larger near the molten pool area and mainly along z-direction. Finally, it’s verified that the analysis results are consistent with actual situation by the experiments with same process parameters.
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Wang, X. B. "Nonuniform Temperature Distribution in Adiabatic Shear Band Using Measured Shear Stress-Shear Strain Curve in Torsion of Thin-Walled Tube Aluminium Alloy Specimen and Gradient-Dependent Plasticity." Materials Science Forum 519-521 (July 2006): 865–70. http://dx.doi.org/10.4028/www.scientific.net/msf.519-521.865.
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Gradient-dependent plasticity where a characteristic length is involved to consider the microstructural effect (interactions and interplaying among microstructures due to the heterogeneous texture) and the measured nonlinear shear stress-shear strain curves for different loading strain rates are used to calculate the distribution of local temperature rise in adiabatic shear band (ASB) for aluminum-lithium alloy specimen of thin-walled tube in dynamic torsion test. ASB is assumed to initiate just at peak shear stress in the specimen. The temperature rise in ASB is decomposed into the uniform temperature rise in strain-hardening stage and the nonuniform temperature rise in strain-softening stage. The former depends on the measured nonlinear shear stress-shear strain curve prior to the peak, the density, the work to heat conversion factor and the heat capacity. The latter is related to the softening branch of the measured nonlinear shear stress-shear strain curve, the internal length parameter and the physical parameters. For binary Al-Li alloy, the predicted maximum temperatures in ASB are 413K at strain rate of 2000s-1 and 433K at strain rate of 2600s-1. These peak temperatures are lower than the recrystallization and phase transformation temperatures. Higher loading strain rate results in higher pre-peak and post-peak temperature rises, steeper profile of local temperature and higher peak local temperature in ASB. These predictions qualitatively agree with the previously analytical solution for ductile metal exhibiting linear strain-softening behavior beyond the peak shear stress based on gradient-dependent plasticity.
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Gnyrya, Aleksei, Yurii Abzaev, and Sergei Korobkov. "Modeling of Stress Distribution During Portland Cement Curing in Temperature Gradient Conditions." IOP Conference Series: Earth and Environmental Science 678, no. 1 (2021): 012006. http://dx.doi.org/10.1088/1755-1315/678/1/012006.
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Zhang, Nengqi, Zhi Chen, Henglin Xiao, Lifei Zheng, and Qiang Ma. "Experimental Study and Numerical Analysis of Temperature Stress in Carbon Fiber-Heated Concrete Pavement." Applied Sciences 14, no. 1 (2023): 359. http://dx.doi.org/10.3390/app14010359.
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Carbon fiber heating technology has been widely used in pavement surfaces in practical engineering projects as an environmentally friendly, efficient, and safe ice melting technique. However, the current design of carbon fiber-heated pavement focuses primarily on the ice melting effect while neglecting the crucial mechanical performance evaluation. Therefore, this study aims to investigate the temperature and thermal strain distributions of concrete pavement through model tests and develop a corresponding three-dimensional numerical model to analyze the temperature stress field distribution of carbon fiber-heated pavement. The accuracy of the numerical model is verified by comparing the model test results with the numerical analysis results. The numerical model test results indicate that the maximum compressive stress near the carbon fiber wire is 4 MPa, while the maximum tensile stress between the two carbon fiber wires is 1 MPa. According to the design standard for highway cement concrete pavement, the temperature stress induced by temperature change is significantly lower than the design value of the material’s inherent strength. In addition, a linear relationship between the depth and temperature gradient affecting temperature stress is observed after establishing a correlation between the temperature gradient and temperature stress. The findings of this study can provide valuable insight into the design of carbon fiber-heated concrete pavements.
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Mohamed, Ashraf R., and Will Hansen. "Effect of Nonlinear Temperature Gradient on Curling Stress in Concrete Pavements." Transportation Research Record: Journal of the Transportation Research Board 1568, no. 1 (1997): 65–71. http://dx.doi.org/10.3141/1568-08.
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Temperature and moisture gradients can lead to significant tensile stresses at the slab top and bottom. Current techniques for assessing the internal stresses due to such gradients are based on the assumption that temperature and moisture distributions through the slab thickness are linear. However, the actual distributions of such gradients have been found to be highly nonlinear. A new closed form solution technique for calculating the stresses in a pavement slab due to nonlinear gradients is introduced. The analysis is separated into two parts. In the first, an expression is presented for calculating the self-equilibrated stresses within a cross section due to internal restraint (i.e., satisfying equilibrium conditions and continuity of the strain field within the cross section). These stresses are independent of slab dimensions and boundary conditions. In the second, the stresses due to external restraint (i.e., self-weight and subgrade reaction) are calculated using an equivalent linear temperature gradient obtained from the first part and existing closed form solutions by Westergaard or Bradbury. The solution to this step includes slab length and boundary conditions. Total internal stresses due to nonlinear gradients are obtained by using the superposition principle. The methodology has been applied to field data from two studies in which the temperature profiles were recorded throughout a 24-hr period. Linear gradient solution methods cannot accurately predict the curling stresses in concrete pavements. This is especially pronounced during nighttime and early morning hours, during which nonlinear analysis predicts tensile stress in both the slab bottom and top before the application of any traffic loading.
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Rogojsz, Grzegorz. "Analysis of temperature gradient in concrete pavement." Bulletin of the Military University of Technology 67, no. 4 (2018): 59–70. http://dx.doi.org/10.5604/01.3001.0012.8493.
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The paper presents the results of experimental research that is the continuation of the research conducted as a part of a Ph.D. dissertation. The experimental research consisted in measuring the temperature at various depths inside a concrete slab, including its surface, and measuring the air temperature. The temperature distribution was measured on a concrete slab with dimensions similar to real road slab dimensions. The aim of the research was to determine the temperature gradient in the concrete slab in Polish climatic conditions and to verify the available analytical methods. Keywords: temperature gradient, concrete pavement, thermal stress in concrete pavement.
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Cai, Liuxi, Yao He, Shunsen Wang, Yun Li, and Fang Li. "Thermal-Fluid-Solid Coupling Analysis on the Temperature and Thermal Stress Field of a Nickel-Base Superalloy Turbine Blade." Materials 14, no. 12 (2021): 3315. http://dx.doi.org/10.3390/ma14123315.
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Based on the establishment of the original and improved models of the turbine blade, a thermal-fluid-solid coupling method and a finite element method were employed to analyze the internal and external flow, temperature, and thermal stress of the turbine blade. The uneven temperature field, the thermal stress distribution characteristics of the composite cooling turbine blade under the service conditions, and the effect of the thickness of the thermal barrier coating (TBC) on the temperature and thermal stress distributions were obtained. The results show that the method proposed in this paper can better predict the ablation and thermal stress damage of turbine blades. The thermal stress of the blade is closely related to the temperature gradient and local geometric structure of the blade. The inlet area of the pressure side-platform of the blade, the large curvature region of the pressure tip of the blade, and the rounding between the blade body and the platform on the back of the blade are easily damaged by thermal stress. Cooling structure optimization and thicker TBC thickness can effectively reduce the high temperature and temperature gradient on the surface and inside of the turbine blade, thereby reducing the local high thermal stress.
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Yao, Jun, Bo Xin, Yadong Gong, and Guang Cheng. "Effect of Initial Temperature on the Microstructure and Properties of Stellite-6/Inconel 718 Functional Gradient Materials Formed by Laser Metal Deposition." Materials 14, no. 13 (2021): 3609. http://dx.doi.org/10.3390/ma14133609.
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Stelite-6/Inconel 718 functionally gradient materials (FGM) is a heat-resisting functional gradient material with excellent strength performance under ultra-high temperatures (650–1100 °C) and, thus, has potential application in aeronautic and aerospace engineering such as engine turbine blade. To investigate the effect of initial temperature on the microstructure and properties of laser metal deposition (LMD) functional gradient material (FGM), this paper uses the LMD technique to form Stelite-6/Inconel 718 FGM at two different initial temperatures: room temperature and preheating (300 °C). Analysis of the internal residual stress distribution, elemental distribution, microstructure, tensile properties, and microhardness of 100% Stelite-6 to 100% Inconel 718 FGM formed at different initial temperatures in a 10% gradient. The experimental results prove that the high initial temperature effectively improves the uneven distribution of internal residual stresses. Preheating slows down the solidification time of the melt pool and facilitates the escape of gases and the homogeneous diffusion of elements in the melt pool. In addition, preheating reduces the bonding area between the gradient layers, enhancing the metallurgical bonding properties between the layers and improving the tensile properties. Compared with Stellite-6/Inconel 718 FGM formed at room temperature, the mean yield strength, mean tensile strength, and mean elongation of Stellite-6/Inconel 718 FGM formed at 300 °C are increased by 65.1 Mpa, 97 MPa, and 5.2%. However, the high initial temperature will affect the hardness of the material. The average hardness of Stellite-6/Inconel 718 FGM formed at 300 °C is 26.9 HV (Vickers hardness) lower than that of Stellite-6/Inconel 718 FGM formed at 20 °C.
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Cai, Weiqiang, Jinliang Yuan, Qingrong Zheng, et al. "Numerical Investigation of Heat/Flow Transfer and Thermal Stress in an Anode-Supported Planar SOFC." Crystals 12, no. 12 (2022): 1697. http://dx.doi.org/10.3390/cryst12121697.
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To elucidate the thermofluid reacting environment and thermal stress inside a solid oxide fuel cell (SOFC), a three-dimensional SOFC model is implemented by using the finite element method in the commercial software COMSOL Multiphysics®, which contains both a geometric model of the full-cell structure and a mathematical model. The mathematical model describes heat and mass transfer, electrochemical reactions, internal reforming reactions, and mechanical behaviors that occur within the cell. A parameter study is performed focusing on the inlet fuel composition, where humidified hydrogen and methane syngas (the steam-to-carbon ratio is 3) as well as the local distribution of temperature, velocity, gas concentrations, and thermal stress are predicted and presented. The simulated results show that the fuel inlet composition has a significant effect on the temperature and gas concentration distributions. The high-temperature zone of the hydrogen-fueled SOFC is located at the central part of units 5, 6, and 7, and the maximum value is about 44 K higher than that of methane syngas-fueled SOFC. The methane-reforming and electrochemical reactions in the anode active layer result in a significant concentration gradient between the anode support layer and the active layer of the methane syngas-fueled SOFC. It is also found that the thermal stress distributions of different fuel inlet compositions are rather different. The maximum stress variation gradient between electrode layers of hydrogen SOFC is larger (44.2 MPa) than that of methanol syngas SOFC (14.1 MPa), but the remaining components have a more uniform stress distribution. In addition, the electrode layer of each fuel SOFC produces a significant stress gradient in the y-axis direction, and stress extremes appear in the corner regions where adjacent assembly components are in contact.
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Peng, Hong Yu, Yu Han Gao, Zhi Qiang Shi, et al. "Investigation of Dislocation Behaviors in 4H-SiC Substrate during Post-Growth Thermal Treatment." Defect and Diffusion Forum 434 (August 22, 2024): 45–49. http://dx.doi.org/10.4028/p-u3d2yi.
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Dislocation behaviors after post-growth thermal treatment were investigated by X-ray topography and KOH etching. Generation of prismatic dislocations were observed in X-ray topography, and density of basal plane dislocations (BPDs) increases with annealing temperature and radial temperature gradient. Distribution of newly generated BPDs in the wafer after thermal treatment is correlated to the resolved shear stress arising from radial temperature gradient.
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Liu, Yujuan, Zhiyuan Ma, and Jiang Liu. "Statistical Evaluation of Uniform Temperature and Thermal Gradients for Composite Girder of Tibet Region Using Meteorological Data." Buildings 14, no. 12 (2024): 3798. http://dx.doi.org/10.3390/buildings14123798.
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To accurately assess the temperature action and effect of steel-concrete composite girder bridges in plateau and cold areas, this paper investigated nearly 50 years of historical meteorological data from 26 meteorological observation stations in the Tibet region of China. Based on the most unfavorable extreme meteorological data at each meteorological station, a finite element model was used to analyze the temperature field of the composite girder. The most unfavorable values of temperature were obtained. The regional differences in temperature actions at different meteorological stations were analyzed, and the isotherm maps of the extreme values of the uniform temperature and thermal gradients were further obtained based on spatial interpolation methods in the ArcGIS program. The study shows that the uniform temperature is significantly affected by the climatic environment, and the isotherm maps provide a visual representation of the geographic distribution pattern of temperature extremes. The maximum and minimum uniform temperatures in Tibet range from 18.28 °C to 42.27 °C and from −41.07 °C to 4.71 °C respectively. The maximum regional difference of positive and negative thermal gradient reaches 11.32 °C and 7.69 °C respectively. The temperature effects calculated using the most unfavorable values of the isotherm map are all more unfavorable than the specification calculations. In particular, the tensile stress of the concrete under the positive thermal gradient reaches 2.91 MPa, which exceeds the standard value of the tensile strength of concrete. This is a significant risk factor for cracking. The compressive stress of the steel girder under a negative thermal gradient reaches 19.35 MPa, which represents a 136% increase compared to the specified value. This increase elevates the risk of instability in the steel girder.
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Nian, Liangxiao, Miaohui Wang, Xueyuan Ge, Xin Wang, and Yifei Xu. "Thermo-Mechanical Coupling Numerical Simulation for Extreme High-Speed Laser Cladding of Chrome-Iron Alloy." Coatings 13, no. 5 (2023): 879. http://dx.doi.org/10.3390/coatings13050879.
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With the aim to improve cladding coating quality and prevent cracking, this paper established an extreme high-speed laser cladding thermo-mechanical coupling simulation model to study the evolution of the temperature field and the residual stress distribution. Process parameters that impacted the macroscopic morphology of single-pass coatings were investigated. Numerical calculations and temperature field simulations were performed based on the process parameter data to validate the effects of the temperature gradient and cooling rate on the coating structure and the residual stress distribution. The results showed that a good coating quality could be achieved using a laser power of 2400 W, a cladding speed of 20 m/min, and a powder feeding rate of 20.32 g/min. The coatings’ cross-sectional morphology corresponded well with the temperature distribution predicted by the numerical modeling of the melt pool. The microstructure of the molten coatings was affected by the temperature gradient and the cooling rate, which varied greatly from the bottom to the middle to the top. Maximum residual stress appeared between the bonding region of the coatings and the substrate, and the coatings themselves had significant residual stress in the form of tensile strains, that were mostly distributed in the direction of the laser cladding.
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Zhang, Limin, and Tao Li. "Microstructure evolution of high carbides Ni-based superalloy during hot compression process." Journal of Physics: Conference Series 3021, no. 1 (2025): 012012. https://doi.org/10.1088/1742-6596/3021/1/012012.
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Abstract The high carbides Ni-based superalloy was conducted with a 60% deformation amount to investigate the hot compression behavior by the Gleeble hot compression simulation experiment under the deformation temperature of 1000 °C, 1100°C, and 1200 °C with the strain rate of 0.1 s−1. The microstructure evolution, stress distribution, and carbide characteristics of the superalloy under different hot compression conditions were analyzed using ECCI and EBSD techniques. The results indicate that when the deformation temperature was 1000 °C there was a larger stress gradient, and higher recrystallization driving energy, but phase transition or recrystallization didn’t occur. When the deformation temperature was 1100 °C or 1200 °C there was less stress gradient and more recrystallization microstructure, and the carbides would undergo phase transformation, M6C + γ → M6C + M23C6 + γ → M23C6 + γ. At the same time, M23C6 underwent decomposition, the alloy elements such as Cr, W, and Mo dissolved back into γ matrix, and the ellipsoidal M23C6 became the network. There were no cracks around the carbides at different deformation temperatures, but the carbides can’t exist stably at higher temperatures than 1100 °C, therefore the service temperature of the alloy should be below 1100 °C.
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Fang, Qihong, Pei Zhao, Jia Li, Hong Wu, and Jing Peng. "Unveiling Temperature Distribution and Residual Stress Evolution of Additively Manufactured Ti6Al4V Alloy: A Thermomechanical Finite Element Simulation." Metals 15, no. 1 (2025): 83. https://doi.org/10.3390/met15010083.
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The performance of the selective electron beam melting (SEBM) products depends on the SEBM-induced temperature and stress. Here, the thermomechanical finite element simulations are conducted to investigate the dynamic evolution of temperature and the thermal stress of melt pool during the SEBM process of Ti6Al4V alloys under various processing parameters and scanning strategies. The results show that the melt pool undergoes three stages of preheating, melting, and remelting under the influence of adjacent scanning tracks. This complex thermal history drives significant changes in thermal stress within the melt pool. After adjusting the processing parameters, it is found that a low scanning speed and high electron beam energy result in a high temperature gradient and stress in the molten pool. Compared to the electron beam energy, the scanning speed has a more significant impact on temperature and residual stress. For the dual-electron-beam scanning strategy, the coupling thermal effect between electron beams can reduce the temperature gradient of the melt pool, thereby suppressing the formation of columnar crystals. The electron beam energy of 300 W and the scanning speed of 1.5 m/s can be selected under various scanning strategies, which are expected to suppress the formation of coarse and columnar β grains and achieve relatively low residual stress. These results contribute to providing a theoretical basis for selecting optimized process parameters and scanning strategies.
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Liu, Zengwu, Shuai Luo, and Menglin Jiang. "Study on the Temperature Model and Influence Effect of Uncovered Steel Box Girder with Large Height–Width Ratio and Straight Web Plate." Buildings 15, no. 11 (2025): 1818. https://doi.org/10.3390/buildings15111818.
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While building the steel–concrete composite girder bridge by means of the incremental launching method, the steel box is directly in the sunlight, and the temperature impact should not be neglected. However, the existing specifications fail to offer the temperature gradient pattern applicable to the steel box featuring a significant height–width ratio and straight web. This paper, relying on the Fenshui River Bridge situated in the southwest region of China, carried out a temperature test. By analyzing the experimental data, the rules of temperature changes at the measuring points in various positions of the steel box were studied, and the temperature disparities of the steel box across different seasons were contrasted. Through the analysis of the test data, the rule governing temperature distribution across the height dimension of the cross-section and its change with time were studied, and a model designed to represent the temperature gradient within the steel box was put forward. By utilizing the numerical model, the effect of the temperature gradient on the force acting on the structure in the process of incremental launching was analyzed. The findings indicate that the temperature of the top plate of the steel box is the highest from 14:00 to 16:00. There is a lag phenomenon in the temperature rise in the bottom plate. The greatest temperature disparity between the upper and lower plates of the steel box is not always present in the season when the temperature is comparatively high. The curve of temperature gradient change exhibits nonlinear features, and the variation in temperature is considerable within the scope of 1 m. In this article, a double-broken line temperature gradient model is put forward, with the corresponding temperature gradient of 17.8 °C. The temperature gradient obviously affects the structural stress, changing the stress distribution, and it notably impacts the deformation. The deformation generated on the guide beam due to the temperature gradient makes up 39% of the total deformation. The temperature gradient is not a fixed value. When the steel box girder is under the jacking process, especially while the structure remains in its maximum cantilever condition and is about to cross the pier, the time should be avoided when the temperature gradient is at its highest.
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Li, Qiang, Jing Yuan Yu, Er Yong Zheng, Ze Sun, and Yu Shan Zeng. "Study on Preparation of Gradient Porous Ti by Powder Metallurgy Method." Advanced Materials Research 490-495 (March 2012): 3589–93. http://dx.doi.org/10.4028/www.scientific.net/amr.490-495.3589.
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Gradient porous Ti was prepared by powder metallurgy method using NH4HCO3 as pore former. The effect of content and distribution of NH4HCO3 and sintering temperature on pore characteristic, sintering shrinkage, flexural property was studied. Stress-strain curves of gradient and uniform porous Ti material were compared. The results show the porosity, sintering shrinkage rate and flexural strength vary from 51.8% to 41.3%, from 23.5% to 28.7%, and from 145.7 MPa to 221.6 MPa when the distribution of NH4HCO3 varying form uniformity to gradient. Additionally, with the increase of sintering temperature, the porosity of gradient samples first increases and then decreases. When sintered at 1573K for 2h, the porosity of gradient porous Ti has the maximum of 45.6%. Moreover, there is pseudo yield phenomenon according to the test curve of three points bending of the gradient porous Ti with three layers structure.
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Fan, Bao-Wei, Ke-Qian Zhu, Qiang Shi, Tao Sun, Ning-Yi Yuan, and Jian-Ning Ding. "Effect of glass thickness on temperature gradient and stress distribution during glass tempering." Journal of Non-Crystalline Solids 437 (April 2016): 72–79. http://dx.doi.org/10.1016/j.jnoncrysol.2016.01.008.
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Yin, Wu, Hai Bo Jiang, Lin Bin Zou, Hong Rui Liu, and Jin Hua Zou. "Effect Analysis of Temperature in the Large Continuous Rigid Frame Bridge." Applied Mechanics and Materials 71-78 (July 2011): 1339–43. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.1339.
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Thermal stress is a factor of the large bridge structure cracks which can not be ignored. As a continuous rigid frame bridge in a certain period of Guangzhou ring express way the background, using the general finite element program MIDAS/Civil, only considering the load of temperature effect established the original bridge model, reference the China road and bridge design for temperature effect on the bridge numerical analysis. By section temperature difference and system temperature change getting the stress distribution and the stress distribution of section temperature difference and the system of heating section, cooling section and the system temperature gradient linear combinations ,the stress we got will get a large section of the stress to the actual distribution of bridge crack detection have a good agreement . Cooling load combination get the Maximum tensile stress at the bridge span beam bottom and the result exceeds the tensile strength of concrete, it gets most impact to the end of the beam cracks. On the bridge design to consider the temperature effect the conclusion has some certain reference value.
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Tan, Hongmei, Dacheng Qian, Yan Xu, Mofang Yuan, and Hanbing Zhao. "Analysis of Vertical Temperature Gradients and Their Effects on Hybrid Girder Cable-Stayed Bridges." Sustainability 15, no. 2 (2023): 1053. http://dx.doi.org/10.3390/su15021053.
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The real temperature distribution within 24 h of the main beam in a single-tower hybrid beam cable-stayed bridge is analysed according to its actual section and material parameters, as well as other factors of local atmospheric temperature, geographical environment, and solar intensity. The results show that the internal temperature distribution in the steel–concrete composite beam is uneven, and the temperature of the steel is higher than that at the surface of the concrete slab. Then, a finite element model of the whole bridge is established using the thermal–mechanical sequential coupling function in ABAQUS to acquire the structural response under the action of a 24-h temperature field. The results show that the vertical temperature gradients have a great influence on the longitudinal stress in the lower flange of the steel I-beam, with a maximum compressive stress of 11.9 MPa in the daytime and a maximum tensile stress of 13.36 MPa at midnight. The temperature rise leads to a downward deflection of the main span, and the maximum deflection occurs at the 1/4 main span. There was an obvious temperature gradient in the concrete slab, with a difference between the maximum and minimum value of 14 °C. Similarly, the longitudinal compressive stress of the concrete slab increases with increasing temperature in the daytime, but the peak time is obviously inconsistent with that of the steel beam.
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Liu, Jiang, Yongjian Liu, Lei Jiang, and Ning Zhang. "Long-term field test of temperature gradients on the composite girder of a long-span cable-stayed bridge." Advances in Structural Engineering 22, no. 13 (2019): 2785–98. http://dx.doi.org/10.1177/1369433219851300.
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Bridges are inevitably affected by daily, seasonal and annual air temperature and solar radiation. The thermal effects on bridges, especially for long-span cable-stayed bridges with composite girders, are significant and complicated. The evaluation of temperature distribution has been a primary concern to bridge engineers and researchers. This article presents a more than one-year temperature database of a long-span cable-stayed bridge with a small cantilever length-to-web depth ratio in the composite girder. Uniform temperature, linear temperature difference, thermal curvature, and self-equilibrated thermal stress are considered to imply the characteristics of the temperature distribution in such composite girders. Two profiles (profile 1 and profile 2) for positive vertical temperature gradient and one profile (profile 3) for negative vertical temperature gradient are proposed. The extreme temperature differences with a 100-year return period are determined for each profile with extreme value analysis. Among the three profiles, profile 2 is unique for composite girders with a small cantilever length-to-web depth ratio. Based on parametric studies, profile 2 is revised with the cantilever length-to-web depth ratio for wide applications. Finally, comparisons of vertical temperature gradients are made between the investigated composite girder and the recommendations in Chinese Specification.
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Li, Hui, Yi-Kun Ba, Ning Zhang, Yong-Jian Liu, and Wei Shi. "Temperature Distribution Characteristics and Action Pattern of Concrete Box Girder under Low-Temperature and Cold Wave Conditions." Applied Sciences 14, no. 7 (2024): 3102. http://dx.doi.org/10.3390/app14073102.
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In regions with severe cold and high latitudes, concrete structures are susceptible to cracking and displacement due to uneven temperature stress, which directly impacts their normal utilization. Therefore, to investigate the temperature distribution characteristics of concrete box girders under the combined influence of low temperatures and cold waves, a temperature test was conducted on a model of concrete box girders in Xinjiang Province, China. Based on the measured data, the distribution pattern of the most unfavorable negative temperature differential observed in high-latitude regions was determined. Long-term numerical simulation and extreme value analysis were performed using historical meteorological data, revealing that the vertical negative temperature gradient in the concrete box girder structures follows a composite exponential distribution. The temperature differential at the top complies with Chinese code requirements, while at the bottom, it aligns more closely with British standard BS5400. Statistical analysis of historical meteorological data predicts that the 50-year temperature differential will result in a drop amplitude of 26.42 °C, which is 1.44 times higher than measured values obtained from experiments. The proposed negative temperature gradient pattern for concrete box girders presented in this study can encompass general design codes and provide guidance for designing concrete bridges in severe cold areas.
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Zhao, Tianjian. "Application and optimization of PINNs algorithm to 3D biomechanical heat transfer problems." Molecular & Cellular Biomechanics 22, no. 5 (2025): 1904. https://doi.org/10.62617/mcb1904.
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In order to investigate the effectiveness of the PINNs algorithm in the application of three-dimensional biomechanical heat transfer problems, the study uses the PINNs algorithm to construct a coupled heat-force model to simulate the temperature field and stress field distribution of different biological tissues. The experimental results show that the prediction error of PINNs is controlled within MSE 1.25 × 10−3 K and the maximum stress error is 6.9 Pa under the complex scenarios with a temperature gradient as high as 800 K/m, a heat flux as high as 6000 W/m², and a stress gradient of more than 10⁵ Pa/m. For the three different materials, namely, natural rubber, polymer, and cellular ceramics, the prediction errors are controlled within MSE 1.25 × 10−3 K. The prediction errors are controlled within MSE 1.25 × 10−3 K, and the maximum stress error is 6.9 Pa. The simulations for natural rubber, polymer, and honeycomb ceramics show that the maximum temperature of honeycomb ceramics reaches 350 K, and the thermal stress gradient is as high as 50 MPa/m, while the thermal stress gradient of natural rubber and polymer is only 5 MPa/m and 7 MPa/m, respectively. strong computational efficiency and numerical stability.
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Liu, Yongqi, Qinghui Shang, Yangxia Wang, Donghuang Zhang, and Tiantian Sun. "Fracture Analysis of a Square-Hole Mullite Ceramic Regenerator." Advanced Composites Letters 27, no. 1 (2018): 096369351802700. http://dx.doi.org/10.1177/096369351802700105.
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According to actual working conditions, the heat transformation process of a square-hole honeycomb regenerator was analyzed using a thermo-solid coupling method. The distribution of the temperature field was analyzed first and then, based on the Mohr strength theory, the fracture position of the regenerator was analyzed. It was found that the temperature of the regenerator increased in a wave pattern with increased cycle time. The maximum temperature difference in its steady state was about 240. The variation of the temperature gradient on different parts of the regenerator revealed the same trend with cycle times. The temperature gradient of each node reached the highest at the end of the endothermic period and the beginning of the exothermic period. It was theorized that the position on the center hole with a high temperature gradient would be destroyed first. The stress state in the highest stress point was revealed to be bi-directional compression.
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Shi, Yan Yan, Mao Qiang Zhang, Xiang Feng Kong, and Jin Hua Li. "Study on the Contact Properties for Involute Cylindrical Gear Based on Thermal Analysis." Applied Mechanics and Materials 339 (July 2013): 510–14. http://dx.doi.org/10.4028/www.scientific.net/amm.339.510.
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Aim to the working properties of aviation accessory transmission gear, such as high speed and heavy load, temperature field distribution regularity of standard involute cylindrical gear is analyzed based on indirect coupling analysis method of ANSYS software. And gear surface contact stress distribution regularity under the action of thermal loading and mechanical load is also analyzed. Gear surface real contact condition under working station is analyzed. It is shown from the result that the high speed and heavy loading on the gear teeth produces the bigger temperature gradient, and thermal deformation regularity of gear teeth is determined by temperature field distribution style, while thermal deformation of gear teeth changes contact condition and stress distribution regularity between meshing gear surfaces.
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Zhong, Qi Lin, Shu Yuan Jiang, Huan Ming Chen, and Pin Liu. "3D FEM Simulation Analysis for the Residual Stress to GTAW Welded Joints Based on Adscititious Magnetic Field." Applied Mechanics and Materials 138-139 (November 2011): 775–79. http://dx.doi.org/10.4028/www.scientific.net/amm.138-139.775.
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Aiming at adscititious magnetic field effect GTAW arc, decrease the maximum welding residual which by arc shape be changed, avoid the temperature excessive focus on welding pool, reduce temperature gradient and so on. Arc heat source model of GTAW under the magnetic field was established, also consider physical properties of materials varying with the temperature and the influence transformation, through the method of killing or activating elements treatment such as melting or solidification by welding pool, 3D FEM simulation analysis for the temperature gradient and residual stress size distribution to GTAW welded joints compared to on magnetic field or not. The results show that maximum weld longitudinal residual stress and transverse residual stress were respectively reduced by 12.3% and 13.6% when compared to no magnetic field, also have blind hole measuring method measure welding residual stress, Test measurement and simulation values were basically consistent.
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Hassan, Abdurssoul Abdulhadi. "Numerical investigation on crack analysis of H13 fixed die and structural analysis of moving die with two different materials." Eastern-European Journal of Enterprise Technologies 6, no. 1 (114) (2021): 81–86. https://doi.org/10.15587/1729-4061.2021.244876.
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Die casting is forcing molten metal into a mould with high pressure. Die casting has two dies namely moving die and fixed die where the moving one will move over the fixed die. Die casting is majorly used for high-volume production. This paper focused on the physical phenomenon of die casting for two dies (moving die and fixed die) using two different alloy materials with variable material chemical compositions. The numerical analysis is carried out for the die casting process to determine the crack formation zone by temperature distribution and structural analysis by stress-strain relationship. The numerical analysis is carried out for both the dies. The fixed die is analyzed with an H13 tool steel material with two moving die materials as aluminum alloy (A356) and magnesium alloy (AZ91D). Both the dies (fixed and moving) were designed by using design software and meshing is carried out followed by analysis using the analysis software. The physical parameter for the dies is applied that is temperature distribution is carried out by applying a temperature of 850 °C and 650 °C over the fixed die for aluminum and magnesium alloy, respectively. Structural analysis is carried out for the moving die with a load of 1,000 N for both aluminum and magnesium alloys with 1000 number of iterations. The results from the numerical analysis are derived and analyzed for both temperature distribution and structural analysis. The crack formation zone is found out by means of temperature gradient and the stress-strain relationship is found out by means of structural analysis. From the results, it was concluded that the crack zone is obtained at 1.22E-10 °C/mm and 6.856E-14 °C/mm of thermal gradient and structural analysis in terms of maximum stress of 446.94 MPa and 448.52 MPa for aluminum and magnesium alloys, respectively.
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Huang, Tai Hong, Peng Song, Qiang Ji, Heng Luo, and Jian Sheng Lu. "Influence of Impact Damage on the Thermal Stress Distribution within the EB-PVD Thermal Barrier Coatings." Materials Science Forum 849 (March 2016): 683–88. http://dx.doi.org/10.4028/www.scientific.net/msf.849.683.
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Macroscopic holes often form on gas turbine blades surface by high velocity gas stream with some foreign impact particles during service. The influence of the impact-holes on the thermal stress distribution was investigated in this paper. The thermal stress distribution within the TBCs after impact-damages at high temperature was intensively studied by using finite element method. Analyze equivalent stress and thermal stress, it was found that the macroscopic holes on the surface of ceramic coatings could change the original temperature gradient and it transform the thermal stress distribution in the TBCs without impacting, resulting in the maximum tensile stress area expanding at the crest and promoting the generation of cracks and reducing coatings life. The impact-holes at the edge of the blades changed the former thermal stress distribution completely. The maximum thermal stress region existed in the alumina scale, severely decreases the life of thermal barrier coatings.
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Rahimi, Javad, Esmaeil Poursaeidi, and Ehsan Khavasi. "Stress analysis of a second stage gas turbine blade under asymmetric thermal gradient." Mechanics & Industry 20, no. 6 (2019): 607. http://dx.doi.org/10.1051/meca/2019041.
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In this study the main causes of the failure of a GE-F9 second stage turbine blade were investigated. The stress distribution of the blade which has 6 cooling vents in three modes (with full cooling, closure of half of the cooling channels, and without cooling) was studied. A three dimensional model of the blade was built and the fluid flow on the blade was studied using the FVM method. The stress distribution due to centrifugal forces applied to the blade, temperature gradients and aerodynamic forces on the blade surface was calculated by the finite element model. The results show that the highest temperature gradient and as a result the highest stress value occurs for the semi-cooling state at the areas near the blade root and this status is true for the full cooling mode for the regions far from the root. However, the field observations showed that the failure occurred for the blade with the semi-cooling state (due to closure of some of the channels) at areas far from the root. It is discussed that the main factor of the failure is not the stress values being maximum because in the state of full cooling mode (the state with the maximum stress values) the temperature of the blade is the lowest state and as a result the material properties of the blade show a better resistance to phenomena like hot corrosion and creep.
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Liu, Zun Chao, Ke Wang, Tong Liu, Wei Feng Xu, and Min Shan Liu. "Structural Analysis and Optimization of Transition Section of Convex Tube Sheet." Applied Mechanics and Materials 853 (September 2016): 356–60. http://dx.doi.org/10.4028/www.scientific.net/amm.853.356.
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The convex tube sheet which is used in heat recovery boiler consists of three parts: the high temperature tube sheet, the low temperature tube sheet and the transition section.Three-dimensional finite element model of convex tube sheet in new type of heat recovery boiler is established in this paper. Using the ANSYS Workbench software, thermal stress of the convex tube sheet is analyzed. The temperature fields and thermal stress distribution of convex tube sheet are obtained, and its structure strength is checked. The effects of the high temperature tube sheet thickness, low temperature tube sheet thickness and transition section thickness on the maximum equivalent stress of the convex tube sheet are analyzed. The results show that: temperature of most parts of convex tube sheet is close to the tube side fluid temperature, and the large temperature gradient only existed in the thinner regions of shell side of convex tube sheet; temperature distribution shows obvious skin effect. At the transition section, the temperature along the thickness direction is more evenly distributed, with little change in temperature gradient; larger thermal stress mainly concentrated at tube layout area which close to the shell side of the high temperature tube sheet and the connecting parts of transition section and low temperature tube sheet in the tube side. Through checking the strength intensity, convex tube sheet structural strength meets the requirements.The transition section thickness are optimized. The optimum thickness of the transition section analyzed in this paper is 31mm.
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Zhu, Jian Bing, Zhi Min Su, Cheng Jie Jiang, Zhi Fang Tian, and Xue Lu. "The Numerical Analysis of Gradient Material Replacement on Arch Dam of Stress Concentration Area." Advanced Materials Research 926-930 (May 2014): 693–98. http://dx.doi.org/10.4028/www.scientific.net/amr.926-930.693.
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During operation, due to change of outside temperature, edge of abutment and central part of concrete arch dam is prone to stress concentration, Concrete of tensile stress concentration area appears too large tensile stress easily, which results cracks to affect dam safety. This paper, by changing the material properties, that obtained high strength low elastic modulus of concrete, replaced arch rings with gradient material replacement method, to improve the stress state of dam and enhance strength for dam safety. By comparing the temperature rise with drop of the arch stress distribution area, the relationship of changing elastic modulus and stress has got. Using the VT technology acquire critical values of mutation elastic modulus.
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Chen, Ji Ping, Jian Qing Qian, and Sheng Zhi Li. "Influence of Hot Leveling and Cooling Process on Residual Stresses of Steel Plates." Advanced Materials Research 168-170 (December 2010): 1130–35. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1130.
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A three-dimensional thermo-mechanical coupled model of hot leveling and cooling processes of the steel plate has been conducted with MSC.Superform software. Four kinds of initial temperature distribution patterns have been determined according to literature. The effects of hot leveling and cooling processes on the transversal and longitudinal residual stresses of the steel plate have been analyzed. The results show that the initial temperature distribution patterns have significant influence on the residual stress of the plate. The more uniform temperature distribution patterns along the width of the plate, the smaller residual stress and also the smaller stress fluctuations. The cooling process has greater effect on the residual stress compared with the hot leveling process. The bigger the temperature gradient along the width of steel plate, the larger the residual stress and its fluctuation is. Through the FEM study, the value and direction of transversal and longitudinal residual stresses can be confirmed quantitatively at various positions along the width and length of plate, which can provide guidance to actual measurement of residual stress.
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Jiregna, I. T., and H. G. Lemu. "Thermal stress analysis of disc brake using analytical and numerical methods." IOP Conference Series: Materials Science and Engineering 1201, no. 1 (2021): 012033. http://dx.doi.org/10.1088/1757-899x/1201/1/012033.
Full textAbstract:
Abstract This article presents study of the thermal stress development in brake disc and the associated life cycle of the disc. The thermal stress analysis of disc brake under the first brake application and the influences of thermal loads on stress development of the disc have been investigated. The temperature distribution was conducted as a function of disc thickness and braking time. The study was done on the disc brake of Sports Utility Vehicle with a model of DD6470C. Partial solution approach was used to solve analytical temperature distribution through the thickness. The model was done using representative areas of the disc exposed to high temperature whose distribution result was obtained as a function of disc thickness and braking time. The solutions of coupled thermal transient fields and stress fields were obtained based on thermal-structural coupled analysis. Based on the model developed for the study, the positions of high and low stress formations were investigated, and it has been observed that thermal stress and temperature gradient show similar behavior through the thickness of disc. Generally, high temperature and stress components were found on the rubbing surfaces of the disc.