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Complete Solution of Large Plastic Deformation of Square Plates Under Exponentially Decaying Pulse Loading

Acta Mechanica Solida Sinica 2021年第6期34卷 922-936页

作者： Faliang Chen Lanren tian t.x.yu Ling Zhu Institute of Applied Physics and Computational Mathematics BeijingChina Key Laboratory of High Performance Ship technology(Wuhan University of technology) Ministry of EducationWuhanChina Departments of Naval Architecture Ocean and Structural Engineering School of TransportationWuhan University of TechnologyWuhanChina Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina

the rigid-plastic assumption has greatly simplified the theoretical analysis of dynamic plastic response of *** this framework,a common tool is the modal technique using approximate independent yield criteria,which leads to upper-and lower-bound solutions,but usually with poor *** this paper,by utilizing the membrane factor method(MFM),the large-deflection dynamic plastic response of square plates subjected to exponentially decaying pulse loading is analyzed by taking both the transient response phase and the exact yield criterion into *** on the combination of saturation analysis(SA)and MFM,the complete solutions and regressive formulae of saturated deflection and saturated impulse are *** the dynamic behavior of plates under rectangular pulse loading serves as a benchmark of pulse-equivalent techniques,the large plastic deformation of square plates under short-duration rectangular pulse is also analyzed in ***,by comparing the SA results of pulse-loaded square plates with different boundary conditions,it is found that the saturated deflection and saturated impulse of the fully clamped and simply supported square plates both increase linearly with the pulse amplitude,and the slopes are approximately the same,so the conversion between the SA quantities of plates with different boundary conditions can be easily achieved.

关键词： Exponentially decaying(ED)pulse loading Rectangular pulse loading Membrane factor method(MFM) Saturation analysis(SA) Complete solution

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Elastic-plastic behavior of a semicircular frame being pressed against a rigid plane

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Acta Mechanica Sinica 2008年第4期24卷 419-432页

作者： x.W.Zhang J.L.Yang t.x.yu Institute of Solid Mechanics Beihang University Beijing 100083 China Department of Mechanical Engineering Hong Kong University of Science and Technology Kowloon Hong Kong China

As a simplified structural model, a semicircular frame is used to study the crashworthiness behavior of an aircraft fuselage. the quasi-static large elastic-plastic deformation of a semicircular frame in the process of its being pressed against a rigid ground is analyzed. First, based on the linear elastic assumption, the quasi-static large deformation contact process of the frame can be divided into three phases, i.e., point contact, line contact and post-buckling. By means of a shooting method, the relations between the displacement and contact force as well as the distribution of bending moment in the three phases are obtained. then, by assuming an elastic, perfectly-plastic moment-curvature relationship for the semi-circular frame, the contact process is analyzed in detail to reveal the plastic collapse mechanism, the traveling of plastic hinge and the force-displacement relationship. In order to verify the analysis, a preliminary experiment was conducted, in which two types of half rings with clamped ends were pressed by a rigid plate. In addition, a numerical simulation is also conducted by employing ABAQUS to analyze both rectangular cross-sectional beam and I-beam. Finally, the theoretical predictions are compared with the experimental results and numerical solutions, showing that the elastic-plastic analysis can predict the contact process very well.

关键词： Elastic-plastic·Large deformation ·Semicircular frame Contact ·traveling hinge

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Using new bio-plastic(PHA,etc.) to reduce the over-reliance on oil

Using new bio-plastic(PHA,etc.) to reduce the over-reliance ...

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the 2015 International Conference on Advanced Materials and Engineering Structural technology(ICAMESt 2015)

作者： L.Wang D.Z.tang t.x.yu W.Q.Zhu Department of energy resources China University of Geoscience

In the field of polymer materials,the occurrence of the third revolution of the material is *** can not only be applied to traditional plastic products,also widely used in new areas of medicine,oil exploration,3D printing,*** present,with oil prices rising,consumer awareness is growing,and in order to reduce production costs,which represent the commercialization of bio-plastics will be *** back to the history,polyhydroxyalkanoates(PHA) is a kind of material which can replace petrochemical *** has been nearly a century of history since the discovery of PHA,but in a very long time,people did not find its practical *** the 1960’s and 1970’s,the worldwide oil crisis drove people to try to find alternatives to oil,PHA caused concern academia and industry because it had properties similar to conventional plastic *** the past 20 years,our society has been facing depletion of oil resources and environmental pollution constantly growing threat,PHA gets more and more attention because of its fully biodegradable and renewable resources synthesis characteristics,then is considered to be environmentally friendly,"biodegradable plastic".

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An adaptive machine learning-based optimization method in the aerodynamic analysis of a finite wing under various cruise conditions

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theoretical & Applied Mechanics Letters 2024年第1期14卷 27-34页

作者： Zilan Zhang yu Ao Shaofan Li Grace x.Gu Department of Mechanical Engineering University of CaliforniaBerkeley 94720USA Department of Engineering Peking UniversityBeijing 100871China Department of Civil and Environmental Engineering University of CaliforniaBerkeley 94720USA

Conventional wing aerodynamic optimization processes can be time-consuming and imprecise due to the complexity of versatile flight *** of existing literature has considered two-dimensional infinite airfoil optimization,while three-dimensional finite wing optimizations are subject to limited study because of high computational *** we create an adaptive optimization methodology built upon digitized wing shape deformation and deep learning algorithms,which enable the rapid formulation of finite wing designs for specific aerodynamic performance demands under different cruise *** methodology unfolds in three stages:radial basis function interpolated wing generation,collection of inputs from computational fluid dynamics simulations,and deep neural network that constructs the surrogate model for the optimal wing *** has been demonstrated that the proposed methodology can significantly reduce the computational cost of numerical *** also has the potential to optimize various aerial vehicles undergoing different mission environments,loading conditions,and safety requirements.

关键词： Aerodynamic optimization Computational fluid dynamics Radial basis function Finite wing Deep learning neural network

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Comparative analyses of mitogenomes in the social bees with insights into evolution of long inverted repeats in the Meliponini

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Zoological Research 2024年第1期45卷 160-175页

作者： yu-Ran Li Zheng-Wei Wang Richard t.Corlett Wen-Bin yu yunnan Key Laboratory for the Conservation of tropical Rainforests and Asian Elephants&Center for Integrative Conservation Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaYunnan 666303China CAS Key Laboratory of tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaYunnan 666303China Southeast Asia Biodiversity Research Institute Chinese Academy of SciencesMenglaYunnan 666303China University of Chinese Academy of Sciences Shijingshan DistrictBeijing 100049China

the insect mitogenome is typically a compact circular molecule with highly conserved gene ***,mitogenome structural variations have been reported in specific taxa,and gene rearrangements,usually the tRNAs,occur in different *** synapomorphies of mitogenome organizations can provide information for phylogenetic inferences,comparative analyses of mitogenomes have been given increasing ***,most studies use a very few species to represent the whole genus,tribe,family,or even order,overlooking potential variations at lower taxonomic levels,which might lead to some incorrect *** provide new insights into mitogenome organizations and their implications for phylogenetic inference,this study conducted comparative analyses for mitogenomes of three social bee tribes(Meliponini,Bombini,and Apini)based on the phylogenetic framework with denser taxonomic sampling at the species and population *** analyses revealed that mitogenomes of Apini and Bombini are the typical type,while those of Meliponini show diverse variations in mitogenome sizes and *** inverted repeats(IRs)cause significant gene rearrangements of protein coding genes(PCGs)and rRNAs in Indo-Malay/Australian stingless bee *** evolution analyses showed that the lineage with IRs have lower dN/dS ratios for PCGs than lineages without IRs,indicating potential effects of IRs on the evolution of mitochondrial *** finding of IRs and different patterns of gene rearrangements suggested that Meliponini is a hotspot in mitogenome *** conserved PCGs and rRNAs whose rearrangements were found only in the mentioned lineages within Meliponini,tRNA rearrangements are common across all three tribes of social bees,and are significant even at the species level,indicating that comprehensive sampling is needed to fully understand the patterns of tRNA rearrangements,and their implications for phylogenetic inference.

关键词： Social bees Phylogeny Mitogenome structure Gene rearrangement Inverted repeats

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In situ tEM investigation of electron irradiation and aging-induced high-density nanoprecipitates in an Mg-10Gd-3Y-1Zn-0.5Zr alloy

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Journal of Magnesium and Alloys 2024年第5期12卷 1841-1853页

作者： M.Lv H.L.Ge Q.Q.Jin x.H.Shao Y.t.Zhou B.Zhang x.L.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Materials Science and Engineering Research Center Guangxi University of Science and TechnologyLiuzhou 545006China

In-situ electron irradiation and aging are applied to introduce high-density precipitates in an Mg-10Gd-3Y-1Zn-0.5Zr(GWZ1031K,wt.%)alloy to improve the *** results show that the hardness of the Mg alloy after irradiation for 10 h and aging for 9 h at 250℃ is 1.64 GPa,which is approximately 64% higher than that of the samples before being *** is mainly attributed to γ'precipitates on the basal plane after irradiation and the high-density nanoscale β'precipitates on the prismatic plane after aging,which should be closely related to the irradiation-induced homogenous *** latter plays a key role in precipitation *** result paves a way to improve the mechanical properties of metallic materials by tailoring the precipitation through irradiation and aging.

关键词： Mg alloy Electron beam irradiation Hardening Precipitates In-situ tEM

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tensor force impact on shell evolution in neutron-rich Si and Ni isotopes

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Chinese Physics C 2024年第4期48卷 95-106页

作者： S.V.Sidorov A.S.Kornilova t.yu.tretyakova Faculty of Physics Lomonosov Moscow State UniversityMoscow 119991Russia Skobeltsyn Institute of Nuclear Physics Lomonosov Moscow State UniversityMoscow 119991Russia

the influence of the tensor interaction of nucleons on the characteristics of neutron-rich silicon and nickel isotopes was studied in this *** forces are considered within the framework of the Hartree-Fock approach with the Skyrme *** addition of a tensor component of interaction is shown to improve the description of the splittings between different single-particle states and decrease nucleon-nucleon pairing correlations in silicon and nickel *** attention was directed toward the role of isovector tensor forces relevant to the interaction of like nucleons.

关键词： nuclear shell model tensor interaction silicon isotopes nickel isotopes

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A particle-resolved heat-particle-fluid coupling model by DEM-IMB-LBM

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2267-2281页

作者： Ming xia Jinlong Fu Y.t.Feng Fengqiang Gong Jin yu Hunan Key Laboratory of Geomechanics and Engineering Safety Xiangtan UniversityXiangtan411105China Zienkiewicz Institute for Modelling Data and AISwansea UniversitySwanseaSA18EPUK School of Civil Engineering Southeast UniversityNanjing211189China Fujian Research Center for tunneling and Urban Underground Space Engineering Huaqiao UniversityXiamen361021China

Multifield coupling is frequently encountered and also an active area of research in geotechnical *** this work,a particle-resolved direct numerical simulation(PR-DNS)technique is extended to simulate particle-fluid interaction problems involving heat transfer at the grain *** this extended technique,an immersed moving boundary(IMB)scheme is used to couple the discrete element method(DEM)and lattice Boltzmann method(LBM),while a recently proposed Dirichlet-type thermal boundary condition is also adapted to account for heat transfer between fluid phase and solid *** resulting DEM-IBM-LBM model is robust to simulate moving curved boundaries with constant temperature in thermal *** facilitate the understanding and implementation of this coupled model for non-isothermal problems,a complete list is given for the conversion of relevant physical variables to lattice ***,benchmark tests,including a single-particle sedimentation and a two-particle drafting-kissing-tumbling(DKt)simulation with heat transfer,are carried out to validate the accuracy of our coupled *** further investigate the role of heat transfer in particle-laden flows,two multiple-particle problems with heat transfer are *** examples demonstrate that the proposed coupling model is a promising high-resolution approach for simulating the heat-particle-fluid coupling at the grain level.

关键词： Particle-fluid interaction Heat transfer Discrete element method(DEM) Lattice Boltzmann method(LBM) Dirichlet-type thermal boundary Direct numerical simulation

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Féeton(B-L gauge boson)dark matter for the 511-keV gamma-ray excess and the prediction of low-energy neutrino flux

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Chinese Physics C 2024年第8期48卷 76-82页

作者： Jie Sheng yu Cheng Weikang Lin tsutomu t.Yanagida tsung-Dao Lee Institute&School of Physics and Astronomy Shanghai Jiao Tong UniversityChina Key Laboratory for Particle Astrophysics and Cosmology(MOE)&Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai Jiao Tong UniversityShanghai 200240China South-Western Institute For Astronomy Research Yunnan UniversityKunming 650500China Kavli IPMU(WPI) UTIASUniversity of TokyoKashiwa277-8583Japan

the féeton is the gauge boson of the U(1)_(B−L) gauge *** the gauge coupling constant is extremely small,the féeton becomes a candidate for dark *** show that its decay to a pair of an electron and a positron explains the observed Galactic 511-keV gamma-ray excess in a consistent *** féeton dark matter decays mainly into pairs neutrino and *** low-energy experiments with improved directional capability will enable capturing these neutrino *** seesaw-motivated parameter space predicts a relatively short féeton lifetime that is comparable to the current cosmological constraint.

关键词： feeton 511-keV gamma-ray excess low-energy neutrino

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An MPI parallel DEM-IMB-LBM framework for simulating fluid-solid interaction problems

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2219-2231页

作者： Ming xia Liuhong Deng Fengqiang Gong tongming Qu Y.t.Feng Jin yu Hunan Key Laboratory of Geomechanics and Engineering Safety Xiangtan UniversityXiangtan411105China School of Civil Engineering Southeast UniversityNanjing211189China Department of Civil and Environmental Engineering Hong Kong University of Science and TechnologyHong KongChina Zienkiewicz Centre for Computational Engineering Swansea UniversitySwanseaSA18ENUK Fujian Research Center for tunneling and Urban Underground Space Engineering Huaqiao UniversityXiamen361021China

the high-resolution DEM-IMB-LBM model can accurately describe pore-scale fluid-solid interactions,but its potential for use in geotechnical engineering analysis has not been fully unleashed due to its prohibitive computational *** overcome this limitation,a message passing interface(MPI)parallel DEM-IMB-LBM framework is proposed aimed at enhancing computation *** framework utilises a static domain decomposition scheme,with the entire computation domain being decomposed into multiple subdomains according to predefined processors.A detailed parallel strategy is employed for both contact detection and hydrodynamic force *** particular,a particle ID re-numbering scheme is proposed to handle particle transitions across sub-domain *** benchmarks are conducted to validate the accuracy and overall performance of the proposed ***,the framework is applied to simulate scenarios involving multi-particle sedimentation and submarine *** numerical examples effectively demonstrate the robustness and applicability of the MPI parallel DEM-IMB-LBM framework.

关键词： Discrete element method(DEM) Lattice Boltzmann method(LBM) Immersed moving boundary(IMB) Multi-cores parallelization Message passing interface(MPI) CPU Submarine landslides

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