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Mechanical Study of Nano⁃ceramic thermal Barrier Coatings by the Equation of Phonon Radiative Transfer

2006年中国机械工程学会年会暨中国工程院机械与运载工...

作者： ZHOU Yijun*, ZHANG Yongkang* ZHOU Jianzhong* YOU Wenming YIN Chen ZHANG Chengyang *School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013,China Dpartment of Mechanical Engineering, Yangzhou Polytechnic College, Yangzhou 225009,China

A 2.5kW CO2 laser and an X-350A X-ray stress-measuring instrument were adopted in the experiment where stainless steel sheet was studied to evaluate the process parameters of bending with thermal stre

关键词： Laser technology thermal stress orthotropic experimental method residual stress.

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Journal of Harbin Institute of Technology(New Series) 2021年第6期28卷 72-79页

作者： Shiyuan Zhang Beilin Zheng Pengfei He Department of Civil Engineering Fujian University of TechnologyFuzhou 350108FujianChina School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China

Temperature filed,thermal stress,especially tensile stress and J⁃integral are important for thermal barrier coatings(TBCs)under thermal shock.At the micro⁃and nano⁃scale,the energy transport mechanisms are significantly different from those at the macro⁃scale.The temperature fields,which are obtained by combining the Equation of Phonon Radiative Transport(EPRT)(for the nano⁃scale ceramic TBCs)and the Fourier law(for the substrate),are used as the thermal loading in the thermal stress and J⁃integral of an edge in the TBCs analysis by the finite element method.The temperature field and thermal stresses as well as J⁃integral are compared with those which are calculated by applying the Fourier law to both the TBCs and the substrate.The influence of the physical heat properties of the TBCs on the temperature field and thermal stress and J⁃integral have been analyzed in this paper.It is concluded that the temperature,thermal stress,including the tensile and compressive components,and J⁃integral which are calculated with the EPRT,are lower than that calculated with the Fourier law in the TBCs.Moreover,thermal stress in the TBCs increase with increasing phonon speed and relaxation time,but J⁃integral at the crack tip is in the opposite.

关键词： nano⁃ceramic TBCs EPRT the Fourier law thermal stress

Design of Composite Ladle Shroud for Improving thermal Shock Resistance

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China's Refractories 2021年第1期30卷 31-34页

作者： LIU Guoqi LI Hongxia YANG Wengang QIAN Fan YU Jianbin MA Weikui State Key Laboratory of Advanced Refractories Luoyang Institute of Refractories Research Co.Ltd.Luoyang 471039China

A ladle shroud is one of the functional refractories for continuous casting,which undergoes severe thermal shock by molten steel when used without pre-heating.The composite ladle shroud with an insulating liner presents excellent thermal shock resistance.Finite element simulation is an effective method to explore the maximum thermal stress for predicting the thermal shock resistance of ladle shrouds.In this paper,the influence of the lining materials and the structure of ladle shrouds on the thermal stress distribution is systematically researched.The working mechanism of the lining material on the body material is also presented.Lining materials with low thermal expansion,elastic modulus and thermal conductivity are helpful to improve the thermal shock resistance and an optimum lining thickness is suggested.The lining material can both serve as thermal resistance for the body material to buffer the thermal stress,and apply a strain load to the body material by the thermal strain to increase the stress.

关键词： composite ladle shroud thermal shock resistance finite element simulation thermal stress

Investigation of temperature effect on stress of flexspline

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Applied Mathematics and Mechanics(English Edition) 2014年第6期35卷 791-798页

作者：项青尹征南 Shanghai Institute of Applied Mathematics & Mechanics Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University

The effect of temperature loading on the stress of a flexspline is investigated. Based on the geometric and mechanical characteristics of the harmonic gear flexspline, a circular thin shell model is presented in this paper. The theoretical solution for the flexspline under different displacement loads and different temperature fields is derived. Meanwhile, an impact factor formula, which reflects the effect of the temperatures of the inner and outer surfaces of the flexspline on the stress of the flexspline, is presented. Finally, numerical calculations by the finite element method （FEM） are adopted to verify the corresponding conclusions.

关键词： thermal stress harmonic flexspline thin shell finite element method （FEM）

Effects of balancing selection and microhabitat temperature variations on heat tolerance of the intertidal black mussel Septifer virgatus

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Integrative Zoology 2020年第5期15卷 416-427页

作者： Guodong HAN Wei WANG Yunwei DONG The Dongshan Marine Observation and Research Station of Fujian province(Xiamen University) Fujian 363000China College of Life Science Yantai UniversityShandong 264005China Fisheries College Ocean University of ChinaShandong 266003China

Realistic assessments of the impacts of global warming on population extinction risk are likely to require an integrated analysis of the roles of standing genetic variation,microhabitat thermal complexity,and the inter-individual variation of heat tolerance due to both genetic differences and seasonal acclimatization effects.Here,we examine whether balancing selection and microhabitat temperature heterogeneity can interact to enhance the population persistence to thermal stress for the black mussel Septifer virgatus.We deployed biomimetic data loggers on the shore to measure the microhabitat-specific thermal variation from June 2014 to April 2016.thermal tolerance of specimens was indexed by measuring effects of temperature on heart rate.Genotyping of specimens was performed using double digestion restriction association RADSeq(ddRADseq).Our results show that inter-individual variations in thermal tolerance correlate significantly with genetic differences at some specific gene loci,and that heterozygotes have higher thermal tolerances than homozygotes.The observed seasonal changes in genotype frequency suggest that these loci are under balancing selection.The ability of thermally resistant heterozygotes to survive in sun-exposed microhabitats acts to balance the loss of homozygotes during summer and enable the persistence of genetic polymorphisms.Population persistence of the mussel is also facilitated by the micro-scale variation in temperature,which provides refugia from thermal stress.Our results emphasize that inter-individual variation in thermal tolerance and in microhabitat heterogeneity in temperature are important for the persistence of populations in rocky shore habitats.

关键词： evolutionary adaptation global warming intertidal species microhabitat heterogeneity in temperature thermal stress

Influence of particle size on the breaking of aluminum particle shells

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Chinese Physics B 2022年第7期31卷 454-460页

作者：王天一周正青彭剑平高玉坤张英华 School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China Zhaojin Mining Industry Co. LtdZhaoyuan 265400China

Rupturing the alumina shell(shell-breaking)is a prerequisite for releasing energy from aluminum powder.thermal stress overload in a high-temperature environment is an important factor in the rupture of the alumina shell.COMSOL Multiphysics was used to simulate and analyze the shell-breaking response of micron-scale aluminum particles with different particle sizes at 650℃in vacuum.The simulation results show that the thermal stability time and shell-breaking response time of 10μm–100μm aluminum particles are 0.15μs–11.44μs and 0.08μs–3.94μs,respectively.They also reveal the direct causes of shell breaking for aluminum particles with different particle sizes.When the particle size is less than 80μm,the shell-breaking response is a direct result of compressive stress overload.When the particle size is between80μm and 100μm,the shell-breaking response is a direct result of tensile stress overload.This article provides useful guidance for research into the energy release of aluminum powder.

关键词： aluminum particle shell–core structure thermal stress shell-breaking

Would behavioral thermoregulation enable pregnant viviparous tropical lizards to cope with a warmer world?

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Integrative Zoology 2017年第5期12卷 379-395页

作者： Saúl LÓPEZ-ALCAIDE Miguel NAKAMURA Eric N.SMITH Enrique MARTÍNEZ-MEYER Departament of Zoology Institute of BiologyNational Autonomous University of MexicoMexico CityMexico Center for Research in Mathematics GuanajuatoMexico Amphibian and Reptile Diversity Research Center and Department of Biology University of Texas at ArlingtonArlingtonTexasUSA

Sceloporus lizards depend on external heat to achieve their preferred temperature(Tsel)for performing physiological processes.Evidence both in the field and laboratory indicates that pregnant females of this Genus select body temperatures(Tb)lower than 34℃ as higher temperatures may be lethal to embryos.Therefore,thermoregulation is crucial for successful embryo development.Given the increase in global air temperature,it is expected that the first compensatory response of species that inhabit tropical climates will be behavioral thermoregulation.We tested whether viviparous Sceloporus formosus group lizards in the wild exhibited differences in thermoregulatory behavior to achieve the known Tsel for developing embryos regardless of local thermal conditions.We quantified field active body temperature,thermoregulatory behavior mechanisms(time of sighting,microhabitat used and basking time)and available microhabitat thermal conditions(i.***.operative temperature)for 10 lizard species during gestation,distributed along an altitudinal gradient.We applied both conventional and phylogenic analyses to explore whether Tb or behavioral thermoregulation could be regulated in response to different thermal conditions.These species showed no significant differences in field Tb during gestation regardless of local thermal conditions.In contrast,they exhibited significant differences in their behavioral thermoregulation associated with local environmental conditions.Based on these observations,the differences in thermoregulatory behavior identified are interpreted as compensatory adjustments to local thermal conditions.We conclude that these species may deal with higher temperatures predicted for the tropics by modulating their thermoregulatory behavior.

关键词： altitudinal gradient behavior global warming Sceloporus formosus thermal stress

Influence of water environment on paint removal and the selection criteria of laser parameters

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Chinese Physics B 2022年第6期31卷 363-373页

作者：张丽君周凯南冯国英韩敬华谢娜肖婧 College of Electronics and Information Engineering Sichuan UniversityChengdu 610065China Laser Fusion Research Center China Academy of Engineering PhysicsMianyang 621999China Science and Technology on Plasma Physics Laboratory Mianyang 621999China Southwest Institute of Technical Physics Chengdu 610041China

Laser paint removal in a water environment does not diffuse ablation pollution products into air.Characteristics of water,such as high specific heat and heat flux,generate different effects of the laser paint removal than in an air environment.In this study,the effects of air and water environments on the mechanism and effect of laser paint removal are analyzed and compared experimentally and theoretically.In air,thermodynamic ablation causes removal of paint,whereas in water,stress coupled with plasma shock waves cause tear and splash removal of paint layers after fracture and damage.Fracture and pressure thresholds of the paint and substrate,respectively,indicate the optimum energy density range for laser paint removal in water,providing a reference for engineering applications.

关键词： paint removal by laser water environment thermal stress laser plasma

Electromigration-induced cracks in Cu/Sn_(3.5)Ag/Cu solder reaction couple at room temperature

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Journal of Semiconductors 2009年第3期30卷 35-38页

作者：何洪文徐广臣郭福 College of Materials Science and Engineering Beijing University of Technology

Electromigration （EM） behavior of Cu/Sn3.5Ag/Cu solder reaction couple was investigated with a high current density of 5 × 10^3 A/cm^2 at room temperature. One dimensional structure, copper wire/solder ball/copper wire SRC was designed and fabricated to dissipate the Joule heating induced by the current flow. In addition, thermomigration effect was excluded due to the symmetrical structure of the SRC. The experimental results indicated that micro-cracks initially appeared near the cathode interface between solder matrix and copper substrate after 474 h current stressing. With current stressing time increased, the cracks propagated and extended along the cathode interface. It should be noted that the continuous Cu6Sn5 intermetallic compounds （IMCs） layer both at the anode and at the cathode remained their sizes. Interestingly, tiny cracks appeared at the root of some long columntype Cu6Sn5 at the cathode interface due to the thermal stress.

关键词： electromigration cracks intermetallic compounds thermal stress