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Influence of recrystallization on tungsten divertor monoblock under high heat flux

Tungsten 2022年第3期4卷 194-202页

作者： Yu-Zhong Jin Xiang Liu You-Yun Lian Jiu-Peng Song Southwestern Institute of Physics Chengdu610225China Xiamen Tungsten Co.Ltd Xiamen361021China

Extremely high heat flux reaching 20 MW·m^(−2) can be foreseen for the future fusion reactor.Such high heat flux would induce recrystallization of tungsten(W)material,leading to significant strength loss of tungsten material and increment of ductility at high temperature,in particular when the temperature is much higher than its ductile-to-brittle transition temperature(DBTT).In this paper,an International Thermonuclear Experimental Reactor(ITER)-like tungsten divertor monoblock is modeled,and benchmark has been done first to get consistent results with ITER.Then,the monoblock structure has been optimized in order to get a lowest possible temperature and stress during heating and cooling phase separately compared to the baseline structure.Structural analysis of two kinds of states:stress-relieved tungsten and recrystallized tungsten using finite element method has been performed,aiming at finding out the recrystallization impact on the mechanical behavior of tungsten in divertor monoblock under cyclic high heat flux.Damages due to progressive deformation and time-independent fatigue lifetime of these two states of tungsten have been assessed and compared according to criteria The Structural Design Criteria for ITER In-vessel Components.Finally,the impact of different material recrystallization temperature on mechanical behavior has been explored under stationary heat load.The result shows that after recrystallization,thermal stress of tungsten material can be released by the larger plastic deformation compared to the stress-relieved tungsten.However,it is easier for recrystallized tungsten to get damaged due to progressive deformation as well as fatigue under 20 MW·m^(−2) cyclic heat flux than stress-relieved tungsten because of its relatively lower yield strength and larger plastic strain,which would cause low-cycle strain fatigue.Furthermore,tungsten with lower recrystallization temperature distorts more seriously,and therefore,it can be predicted the cracks would be initiated more easily.

关键词： Tungsten Finite element method Divertor High heat flux thermal stress

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A new analytical model for thermal stresses in multi-phase materials and lifetime prediction methods

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Acta Mechanica Sinica 2008年第2期24卷 189-206页

作者： Ladislav Ceniga Institute of Materials Research Slovak Academy of Sciences Watsonova 47 04353 Koice Slovak Republic

Based on the fundamental equations of the mechanics of solid continuum, the paper employs an analytical model for determination of elastic thermal stresses in isotropic continuum represented by periodically distributed spherical particles with different distributions in an infinite matrix, imaginarily divided into identical cells with dimensions equal to inter-particle distances, containing a central spherical particle with or without a spherical envelope on the particle surface. Consequently, the multi-particle-（envelope）- matrix system, as a model system regarding the analytical modelling, is applicable to four types of multi-phase materials. As functions of the particle volume fraction v, the inter-particle distances dl, d2, d3 along three mutually per- pendicular axes, and the particle and envelope radii, R1 and R2, respectively, the thermal stresses within the cell, are originated during a cooling process as a consequence of the difference in thermal expansion coefficients of phases rep- resented by the matrix, envelope and particle. Analytical-（experimental）-computational lifetime prediction methods for multi-phase materials are proposed, which can be used in engineering with appropriate values of parameters of real multi-phase materials.

关键词： thermal stress Multi-phase material Lifetime prediction Analytical modelling

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Adaptive nodeless variable finite elements with flux-based formulation for thermal-structural analysis

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Acta Mechanica Sinica 2008年第2期24卷 181-188页

作者： Sutthisak Phongthanapanich Pramote Dechaumphai Department of Mechanical Engineering Technology College of Industrial Technology King Mongkut's Institute of Technology North Bangkok Bangkok 10800 Thailand Mechanical Engineering Department Chulalongkorn University Bangkok 10330 Thailand

A nodeless variable element method with the fluxbased formulation is developed to analyze two-dimensional thermal-structural problems. The nodeless variable formula- tion provides accurate temperature distributions to yield more accurate thermal stress solutions. The flux-based formulation is used to reduce the complexity in deriving the finite element equations as compared to the conventional finite element method. The solution accuracy is further improved by implementing an adaptive meshing technique to generate finite element meshes that can adapt and move along with the transient solution behavior. A version of a nearly optimal element size determination is proposed to provide high convergence rate of the predicted solutions. The combined procedure is evaluated by solving several thermal, structural, and thermal stress problems.

关键词： Keywords Flux-based formulation Nodeless variablefinite element method thermal stress

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Anaerobic metabolism and thermal tolerance:The importance of opine pathways on survival of a gastropod after cardiac dysfunction

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Integrative Zoology 2017年第5期12卷 361-370页

作者： Guodong HAN Shu ZHANG Yunwei DONG State Key Laboratory of Marine Environmental Science College of Ocean and Earth SciencesXiamen UniversityXiamenChina Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources Xiamen UniversityXiamenChina

Organisms on rocky shores are frequently exposed to high temperatures,which cause impairment of cardiac function and retard cellular oxygen delivery.However,some gastropods can survive at several degrees Celsius higher than their Arrhenius break temperature of cardiac function(ABT),indicating the importance of anaerobic metabolism for their thermal tolerance.We measured the global molecular responses to heat stress in limpet Cellana toreuma using 454 GS-FLX to investigate the variations of genes involved in anaerobic metabolism at high temperatures.Next,the gene expression levels of 4 anaerobic enzymes and activity of alanopine dehydrogenase(AlDH),which is involved in opine pathway,were measured in response to elevated temperature.A total of 19 heat shock proteins(HSPs)were determined using real-time PCR at different temperatures.At high temperatures,the extensive upregulation of HSP genes was an effective but energetically expensive form of protection to prevent thermal damage.The upregulation of hypoxia-inducible factor 1 alpha mRNA indicated the condition of cellular hypoxia and the high gene expression and enzyme activity of AlDH suggested that opine pathway was the main anaerobic pathway.These results implied that anaerobic metabolism was enhanced to provide energy in the face of thermal stress.Our findings highlight the ecological significance of the anaerobic metabolism of gastropods to thermal adaptation.For predicting the ecological impact of global warming on the distribution of gastropods,the role of anaerobic pathways should be evaluated.

关键词： anaerobic metabolism cardiac function enzyme activity thermal stress transcriptome

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thermal Residual stresses in Multilayered Coatings

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Journal of Materials Science & Technology 2005年第4期21卷 599-605页

作者： Xiancheng ZHANG Binshi XU Haidou WANG Yixiong WU State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China National Key Laboratory for Remanufacturing Beijing 100072 China

The mechanical integrity and reliability of coated devices are strongly affected by the residual stresses in thin films and coatings. However, due to the metallurgical complexity of materials, it is rather difficult to obtain a closed-form solution of residual stresses within multilayered coatings （e.g. functionally graded coatings, FGCs）. In this paper,an analytical model is developed to predict the distribution of residual stresses within multilayered coatings. The advantage of this model is that the solution of residual stresses is independent of the number of layers. Specific results are obtained by calculating elastic thermal stresses in ZrO2/NiCoCrAIY FGCs, which consist of different material layers. Furthermore, the residual stress distribution near the edges and the stress-induced failure modes of coating are also analyzed. The topics discussed provide some insights into the development of a methodology for designing fail-safe coating systems.

关键词： Multilayered coatings thermal stress Functionally graded coatings stress distribution stress-induced failure

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Genetic Algorithm for the thermal stresses Optimum Design ofFunctionally Gradient Material Plate

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International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 224-227页

作者： Xiaodan Zhang Zhengbin Tang Changchun Ge(Applied Science School, University of Science and Technology Beijing, Beijing 100083, China) Applied Science School University of Science and Technology Beijing Beijing 100083 China

Based on the thermal stress distribution for functionally gradient material (FGM) plates, a Genetic Algorithm (GA) method for the thermal stresses optimum design of FGM plate with computer technologies is given. The m... 详细信息

关键词： functionally gradient material (FGM) thermal stress Genetic Algorithm (GA) crossover mutation

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Emerging environmental stressors and oxidative pathways in marine organisms:Current knowledge on regulation mechanisms and functional effects

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BIOCELL 2022年第1期46卷 37-49页

作者： MAURA BENEDETTI MARIA ELISA GIULIANI MARICA MEZZELANI ALESSANDRO NARDI LUCIA PITTURA STEFANIA GORBI FRANCESCO REGOLI Dipartimento di Scienze della Vitaedell’Ambiente UniversitàPolitecnica delle MarcheAncona60131Italy

Oxidative stress is a critial condition derived from the imbalance between the genention of reactive oxygen species and the sophisticated network of antioidant mechanisms.Several pollut ants and envronmental factors can afet this system through connected mechanisms,indirect relationships,and cascade effects from pre-transcriptional to catalytic level,by either enhancing intracellular ROS formation or impairing antioxidant defenses.This review summariaces the current kmnowledge on the pro oxidant challenges from emerging environmental stressors threatening marine organisms,such as pharmaceutials microplastics and dimate related ocean changes.Emphasis will be placed on oxidative pathways,including signaling proteins and transcription factors involved in regulation of antioxidant responsiveness.Mechanistic insights and lack of knowdedge will be pointed out by presenting single and combined efects of multiple stessors,unraveling questions to be adresed by future resarch in marine ectoicology.

关键词： Antioxidant Pharmaceuticals Microplastics/Nanoplastics Ocean acidification thermal stress

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Nonlinear temperature characteristic of thermal expansion of Grf/Mg composites

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Transactions of Nonferrous Metals Society of China 2009年第S2期19卷 382-386页

作者：宋美慧修子扬武高辉陈国钦 School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Graphite fiber reinforced magnesium matrix(Grf/Mg)composites were fabricated by squeeze casting technology.M40 graphite fibers were reinforced to AZ91D and ZM6,their thermal expansion behaviors of M40/AZ91D and M40/ZM6 composites in the temperature range from 20 to 490℃were investigated.The results show that the interfacial species and thermal stress have significant influence on the thermal expansion behavior of the composites.Simultaneously,the longitudinal coefficient of thermal expansion of Grf/Mg composites are affected by the thermal stress,interfacial species and yield strength of matrix alloy,it also decreases with increasing temperature and descending rate of longitudinal coefficient of thermal expansion(CTEs)of Grf/Mg composites changed in different temperature ranges.In terms of different descending rates,the curve of coefficient of thermal expansion vs temperature can be divided into three stages.The matrix alloys M40/AZ91D and M40/ZM6 yield at 170 and 155℃in the thermal expansion,respectively.

关键词： magnesium matrix composites thermal expansion interface thermal stress

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thermal Behavior of EAST 2.45 GHz Lower Hybrid Wave Antenna

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Plasma Science and Technology 2010年第6期12卷 743-747页

作者：李军刘甫坤刘亮 Institute of plasma physics Chinese academy of sciences

thermal behavior of the 2.45 GHz lower hybrid wave （LHW） antenna in EAST is investigated. The temperature distribution of the LHW antenna is obtained using the ANSYS code. The thermal stresses and displacements due to thermal loads are calculated. The tempera- tures measured by the thermocouples in the experiment are also presented. All the results of the simulation are discussed. The simulated results offer guidance for the design and manufacture of the antenna.

关键词： LHW antenna temperature finite element thermal stress

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Solution of a problem of thermal stresses in a non-homogeneous thermoelastic infinite medium of isotropic material by finite difference method

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Journal of Ocean Engineering and Science 2019年第3期4卷 256-262页

作者： A.M.Farhan A.M.Abd-Alla Moaiad A.Khder Physics Department Faculty of ScienceJazan UniversitySaudi Arabia Physics Department Faculty of ScienceZagzig UniversityEgypt Mathematics Department Faculty of ScienceSohag UniversityEgypt Department of Computer Science Applied Science UniversityBahrain

The present work deals with a new problem of thermoelasticity for an infinitely long and isotropic circular cylinder of temperature dependent physical properties.The inner and outer curved surfaces of the cylinder are subjected to both the mechanical and thermal boundary conditions.A finite difference model is developed to derive the solution of the problem in which the governing equations are uncoupled linear partial differential equations.The transient solution at any time can be evaluated directly from the model.In order to demonstrate the efficiency of the present model we consider a suitable material and obtain the numerical solution of displacement,temperature,and stresses inside the cylinder for the homogeneous-dependent material properties of the medium.The results are analyzed with the help of different graphical plots.

关键词： thermal stress Thermoelasticity Wave propagation Finite difference Method Non-homogeneous medium

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