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The dynamic relaxation form finding method aided with advanced recurrent neural network 被引量:1
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作者 Liming Zhao Zhongbo Sun +1 位作者 Keping Liu Jiliang Zhang 《CAAI Transactions on Intelligence Technology》 SCIE EI 2023年第3期635-644,共10页
How to establish a self‐equilibrium configuration is vital for further kinematics and dynamics analyses of tensegrity mechanism.In this study,for investigating tensegrity form‐finding problems,a concise and efficien... How to establish a self‐equilibrium configuration is vital for further kinematics and dynamics analyses of tensegrity mechanism.In this study,for investigating tensegrity form‐finding problems,a concise and efficient dynamic relaxation‐noise tolerant zeroing neural network(DR‐NTZNN)form‐finding algorithm is established through analysing the physical properties of tensegrity structures.In addition,the non‐linear constrained opti-misation problem which transformed from the form‐finding problem is solved by a sequential quadratic programming algorithm.Moreover,the noise may produce in the form‐finding process that includes the round‐off errors which are brought by the approximate matrix and restart point calculating course,disturbance caused by external force and manufacturing error when constructing a tensegrity structure.Hence,for the purpose of suppressing the noise,a noise tolerant zeroing neural network is presented to solve the search direction,which can endow the anti‐noise capability to the form‐finding model and enhance the calculation capability.Besides,the dynamic relaxation method is contributed to seek the nodal coordinates rapidly when the search direction is acquired.The numerical results show the form‐finding model has a huge capability for high‐dimensional free form cable‐strut mechanisms with complicated topology.Eventually,comparing with other existing form‐finding methods,the contrast simulations reveal the excellent anti‐noise performance and calculation capacity of DR‐NTZNN form‐finding algorithm. 展开更多
关键词 dynamic relaxation form‐finding noise‐tolerant zeroing neural network sequential quadratic programming TENSEGRITY
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Effective loading algorithm associated with explicit dynamic relaxation method for simulating static problems 被引量:4
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作者 赵崇斌 彭省临 +2 位作者 刘亮明 HOBBS B E ORD A 《Journal of Central South University》 SCIE EI CAS 2009年第1期125-130,共6页
Based on the fact that a static problem has an equivalent wave speed of infinity and a dynamic problem has a wave speed of finite value, an effective loading algorithm associated with the explicit dynamic relaxation m... Based on the fact that a static problem has an equivalent wave speed of infinity and a dynamic problem has a wave speed of finite value, an effective loading algorithm associated with the explicit dynamic relaxation method was presented to produce meaningful numerical solutions for static problems. The central part of the explicit dynamic relaxation method is to turn a time-independent static problem into an artificial time-dependent dynamic problem. The related numerical testing results demonstrate that: (1) the proposed effective loading algorithm is capable of enabling an applied load in a static problem to be propagated throughout the whole system within a given loading increment, so that the time-independent solution of the static problem can be obtained; (2) the proposed effective loading algorithm can be straightforwardly applied to the particle simulation method for solving a wide range of static problems. 展开更多
关键词 numerical simulation static systems dynamic relaxation loading algorithm
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A method to simulate multilayer welding process: Node dynamic relaxation method 被引量:7
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作者 高嘉爽 杨建国 +2 位作者 方洪渊 胡军峰 王涛 《China Welding》 EI CAS 2009年第3期42-45,共4页
A new method called node dynamic relaxation is proposed to simulate multilayer welding. A two dimensional plane strain model for multilayer welding is simulated and the results show that mesh distortion can be decreas... A new method called node dynamic relaxation is proposed to simulate multilayer welding. A two dimensional plane strain model for multilayer welding is simulated and the results show that mesh distortion can be decreased, and it is also found that the node dynamic relaxation is a kind of method to calculate welding deformation accurately by comparing experiment results with simulation results. 展开更多
关键词 finite element analysis multilayer welding node dynamic relaxation
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Node dynamic relaxation method: principle and application 被引量:2
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作者 Hong-Yuan FANG Tao WANG Jun-Feng HU Jian-Guo YANG 《Frontiers of Materials Science》 SCIE CSCD 2011年第2期179-195,共17页
Two main methods, inactive eiement method and quiet element method, to simulate the process of multilayer :and multipass welding:were reviewed, and the shortcomings of both methods were diScussed as well Based on ... Two main methods, inactive eiement method and quiet element method, to simulate the process of multilayer :and multipass welding:were reviewed, and the shortcomings of both methods were diScussed as well Based on these analyses, a method called node dynamic relaxation method was put into forward to simulate the multilayer and multipass welding process, and the principle and application of this method were discussed in detail. The simulating results show that using the node dynamic relaxation method can decrease mesh distortion, improve calculation efficiency, and obtain good simulation results. This method can also be used in the field of simulation addition or removing materials in finite element analysis. 展开更多
关键词 inactive element methodl quiet element methodl node dynamic relaxation method multilayer and multipass Welding finite element analysis (FEA)
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Nonlinear analysis of cable structures using the dynamic relaxation method
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作者 Mohammad REZAIEE-PAJAND Mohammad MOHAMMADI-KHATAMI 《Frontiers of Structural and Civil Engineering》 SCIE EI CSCD 2021年第1期253-274,共22页
The analysis of cable structures is one of the most challenging problems for civil and mechanical engineers.Because they have highly nonlinear behavior,it is difficult to find solutions to these problems.Thus far,diff... The analysis of cable structures is one of the most challenging problems for civil and mechanical engineers.Because they have highly nonlinear behavior,it is difficult to find solutions to these problems.Thus far,different assumptions and methods have been proposed to solve such structures.The dynamic relaxation method(DRM)is an explicit procedure for analyzing these types of structures.To utilize this scheme,investigators have suggested various stiffness matrices for a cable element.In this study,the efficiency and suitability of six well-known proposed matrices are assessed using the DRM.To achieve this goal,16 numerical examples and two criteria,namely,the number of iterations and the analysis time,are employed.Based on a comprehensive comparison,the methods are ranked according to the two criteria.The numerical findings clearly reveal the best techniques.Moreover,a variety of benchmark problems are suggested by the authors for future studies of cable structures. 展开更多
关键词 nonlinear analysis cable structure stiffness matrix dynamic relaxation method
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Relaxation Dynamics in Condensation on Weighted Scale-Free Networks
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作者 TANG Ming LIU Zong-Hua 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第1期252-256,共5页
Most of the realistic networks are weighted scale-free networks. How this structure influences the condensation on it is a challenging problem. Recently, we make a first step to discuss its condensation [Phys. Rev. E ... Most of the realistic networks are weighted scale-free networks. How this structure influences the condensation on it is a challenging problem. Recently, we make a first step to discuss its condensation [Phys. Rev. E 74 (2006) 036101] and here we focus on its evolutionary process of phase transition. In order to show how the weighted transport influences the dynamical properties, we study the relaxation dynamics in a zero range process on weighted scale-free networks. We find that there is a hierarchical relaxation dynamics in the evolution and there is a scaling relation between the relaxation time and the jumping exponent. The relaxation dynamics can be illustrated by a mean-field equation. The theoretical predictions are confirmed by our numerical simulations. 展开更多
关键词 relaxation dynamics CONDENSATION scale-free networks
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Dielectric Analysis of Dynamic Fouling Behavior on Surface of Polyethersulfone Composite Ultrafiltration Membrane
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作者 罗明良 温庆志 +1 位作者 刘佳林 刘洪见 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第2期241-248,I0002,共9页
A dielectric analysis model for the fouling layer on the polyethersulfone composite ultrafiltration (UF) membrane and solution system, which consists of the solution, concentration polarization layer (CPL), and ca... A dielectric analysis model for the fouling layer on the polyethersulfone composite ultrafiltration (UF) membrane and solution system, which consists of the solution, concentration polarization layer (CPL), and cake layer, was established by virtue of the interfacial polarization and the electrostatic field theory. The effect of some important parameters, such as the depth, conductivity of CPL, and cake layer, on the dielectric spectroscopy (or dielectric relaxation properties) of the UF system was discussed by the parameter sensitivity analysis and the dielectric measurement. The simulations indicate that the CPL can be created rapidly and the cake layer formation is the dynamic balance process of growth and erosion in the process of UF. The key factor affecting on the dielectric spectrum of UF system is the electrical properties of the CPL and the cake layer. In comparison to the results of dielectric measurement, the simulations indicate that the model proposed in this work is valid and reliable to some degree for describing and explaining the dielectric relaxation phenomenon in UF system. It is very important to further understand the fouling behavior of membrane surface and optimize the controlling techniques of membrane fouling in the process of UF. 展开更多
关键词 Interfacial polarization Cake layer dynamic fouling Ultrafiltration Dielec-tric relaxation
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Kagome Project:Physical and Numerical Modeling Comparison for a Post-formed Elastic Gridshell
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作者 Marc Leyral Quentin Chef +2 位作者 Tom Bardout Romain Antigny Alexis Meyer 《Journal of Civil Engineering and Architecture》 2022年第4期200-226,共27页
An elastic gridshell is an efficient constructive typology for crossing large spans with little material.A flat elastic grid is built before buckling the structure into shape,in active and post-formed bending.The desi... An elastic gridshell is an efficient constructive typology for crossing large spans with little material.A flat elastic grid is built before buckling the structure into shape,in active and post-formed bending.The design and structural analysis of such a structure requires a stage of form finding that can mainly be done:(1)With a physical model:either by a suspended net method,or an active bending model;(2)With a numerical model performed by dynamic relaxation.All these solutions have various biases and assumptions that make them reflect more or less the reality.These three methods have been applied by Happold and Liddell[1]during the design of the Frei Otto’s Mannheim Gridshell which has allowed us to compare the results,and to highlight the significant differences between digital and physical models.Based on our own algorithm called ELASTICA[2],our study focuses on:(1)Comparing the results of the ELASTICA’s numerical models to load tests on physical models;(2)The identification of the various factors that can influence the results and explain the observed differences,some of which are then studied;(3)Applying the results to build a full-scale interlaced lattice elastic gridshell based on the Japanese Kagome pattern. 展开更多
关键词 Interlaced lattice gridshell timber dynamic relaxation numerical modeling physical modeling form finding Kagome.
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Simulations of the flipping images and microparameters of molecular orientations in liquids according to the molecule string model 被引量:3
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作者 王丽娜 赵兴宇 +1 位作者 张丽丽 黄以能 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第8期392-397,共6页
The relaxation dynamics of liquids is one of the fundamental problems in liquid physics, and it is also one of the key issues to understand the glass transition mechanism. It will undoubtedly provide enlightenment on ... The relaxation dynamics of liquids is one of the fundamental problems in liquid physics, and it is also one of the key issues to understand the glass transition mechanism. It will undoubtedly provide enlightenment on understanding and calculating the relaxation dynamics if the molecular orientation flipping images and relevant microparameters of liquids are studied. In this paper, we first give five microparameters to describe the individual molecular string (MS) relaxation based on the dynamical Hamiltonian of the MS model, and then simulate the images of individual MS ensemble, and at the same time calculate the parameters of the equilibrium state. The results show that the main molecular orientation flipping image in liquids (including supercooled liquid) is similar to the random walk. In addition, two pairs of the parameters are equal, and one can be ignored compared with the other. This conclusion will effectively reduce the difficulties in calculating the individual MS relaxation based on the single-molecule orientation flipping rate of the general Glauber type, and the computer simulation time of interaction MS relaxation. Moreover, the conclusion is of reference significance for solving and simulating the multi-state MS model. 展开更多
关键词 relaxation dynamics glass transition Ising model molecular string
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Fast Optical Switching Using Oriented Cyanine Dye-Doped Nematic Liquid Crystal 被引量:1
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作者 金朝辉 李忠玉 KASATANI Kazuo OKAMOTO Hiroaki 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第10期2786-2789,共4页
A cyanine dye, 2-[7-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)-1,3,5-heptatrienyl]-1,3,3-trimethyl-3H-indolium iodide (NK-125), is doped in 4-cyano-4'-pentylbiphenyl (5 CB), and the mixture is sandwiched ... A cyanine dye, 2-[7-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)-1,3,5-heptatrienyl]-1,3,3-trimethyl-3H-indolium iodide (NK-125), is doped in 4-cyano-4'-pentylbiphenyl (5 CB), and the mixture is sandwiched between two pieces of rubbed glass plates. The third-order nonlinear optical properties of the oriented NK-125-SCB layers are measured by the resonant femtosecond degenerate four-wave mixing (DFWM) technique at 760 nm. The third-order nonlinear optical susceptibility of one of the present samples is 5.5×10^-8 esu. The slow DFWM response of the NK-125-SCB layers due to a population grating is accelerated by the increasing laser power because of amplified spontaneous emission (ASE). On the other hand, we do not observe a similar phenomenon for NK-125- polyethylene glycol (PEG-400). Oriented NK-125 molecules in nematic liquid crystals must have very high ASE efficiency. Hence the population grating in a DFWM signal disappears within about 4 ps. It is expected that NK-125-SCB can be used as a material for very fast all-optical switching. 展开更多
关键词 relaxation dynamicS ENERGY-TRANSFER SQUARYLIUM DYE COATING FILMS POLYMER-FILMS FAST-RESPONSE NONLINEARITIES STATE SUSCEPTIBILITY SPECTROSCOPY
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Dramatic Impact of Auxiliary Ligands on the Dynamic Magnetic Relaxation in Tetranuclear Dy^(III)_(2)Zn^(II)_(2) Single Molecule Magnets 被引量:1
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作者 Gao-Peng Li Hong-Fang Xie +3 位作者 Shi-Rui Yang Yun-Long Fu Yi-Quan Zhang Yao-Yu Wang 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2022年第20期2415-2420,共6页
Better understanding the determining factors of dynamic magnetic relaxation in polynuclear lanthanide based single-molecule magnets(SMMs)remains a challenge due to the complexity of such architectures involving intera... Better understanding the determining factors of dynamic magnetic relaxation in polynuclear lanthanide based single-molecule magnets(SMMs)remains a challenge due to the complexity of such architectures involving interactions between the magnetic centers.To address this issue,two structurally related heterometal Dy^(III)_(2)Zn^(II)_(2) SMMs,[Zn_(2)Dy_(2)(L)_(4)(Ac)_(2)(DMF)(CH_(3)OH)]·CH_(3)OH·2H_(2)O(1)and[Zn_(2)Dy_(2)(L)_(4)(Ac)_(2)(DMF)_(2)]·4CH_(3)CN(2)(H_(2)L=(E)-2-((2-hydroxy-3-methoxybenzylidene)amino)-4-methyphenol,DMF=N,N-dimethylformamide),are introduced and investigated.Through modifying the auxiliary ligands on one Dy^(III) site while retaining that on the other Dy^(III),the intramolecular magnetic interactions and relaxation dynamics in these two heterometallic-Dy^(III)_(2)Zn^(II)_(2) SMMs can be tuned,demonstrating a dramatic change in the magnet relaxation behavior with energy barrier changing from a negligible value for 1 to 305 K for 2.Ab initio calculations reveal that changing the coordination geometries on the Dy^(III) sites can significantly affect the magnetic interactions as well as single-ion anisotropy. 展开更多
关键词 Single-molecule magnets dynamic magnetic relaxation DYSPROSIUM Auxiliary ligands Ab initio calculations
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Hydrogen-bonded Intramolecular Charge Transfer Excited State of Dimethylaminobenzophenone using Time Dependent Density Functional Theory
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作者 Yu-ling Chu Zhong Yang +4 位作者 Zhe-feng Pan Jing Liu Yue-yi Han Yong Ding Peng Song 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2012年第6期654-658,I0003,共6页
Density functional theory and time-dependent density-functional theory have been used to investigate the photophysical properties and relaxation dynamics of dimethylaminobenzophe- none (DMABP) and its hydrogen-bonde... Density functional theory and time-dependent density-functional theory have been used to investigate the photophysical properties and relaxation dynamics of dimethylaminobenzophe- none (DMABP) and its hydrogen-bonded DMABP-MeOH dimer. It is found that, in non- polar aprotic solvent, the transitions from So to S1 and S2 states of DMABP have both n→π and π→π* characters, with the locally excited feature mainly located on the C=O group and the partial CT one characterized by electron transfer mainly from the dimethylaminophenyl group to the C=O group. But when the intermolecular hydrogen bond C=O…H-O is formed, the highly polar intramolecular charge transfer character switches over to the first excited state of DMABP-MeOH dimer and the energy difference between the two low- lying electronically excited states increases. To gain insight into the relaxation dynamics of DMABP and DMABP-MeOH dimer in the excited state, the potential energy curves for con- formational relaxation are calculated. The formation of twisted intramolecular charge trans- fer state via diffusive twisting motion of the dimethylamino/dimethylaminophenyl groups is found to be the major relaxation process. In addition, the decay of the Si state of DMABP-MeOH dimer to the ground state, through nonradiative intermolecular hydrogen bond stretching vibrations, is facilitated by the formation of the hydrogen bond between DMABP and alcohols. 展开更多
关键词 HYDROGEN-BOND Intramolecular charge transfer relaxation dynamic Twistingdynamic
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Singlet relaxation dynamics and long triplet lifetimes of thiophene-coupled perylene diimides dyads:New insights for high efficiency organic solar cells
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作者 Qingxuan Fan Wenjun Ni +2 位作者 Lingcheng Chen Gagik G.Gurzadyan Yi Xiao 《Chinese Chemical Letters》 SCIE CAS CSCD 2020年第11期2965-2969,共5页
In the active layer of organic solar cells(OSCs),the lifetime of triplet excitons is one of the decisive factors in the diffusion length and therefore has important impact on the power conversion efficiency of the dev... In the active layer of organic solar cells(OSCs),the lifetime of triplet excitons is one of the decisive factors in the diffusion length and therefore has important impact on the power conversion efficiency of the devices.Herein,we have investigated singlet excited state relaxation dynamics and their triplet exciton lifetimes of two thiophene-coupled perylene diimides(PDI)dyads(2 PDI-Th and fused-2 PDI-Th),in order to provide a unique explanation in depth on their different performances in OSC devices.From the transient absorption(TA)spectra,the singlet excitons of 2 PDI-Th form excimers in the time scale of 1.5 ps.Then the excimers go into the triplet state via intersystem crossing(ISC).In fused-2 PDI-Th,triplet excitons are generated directly from the singlet excited excitons via the efficient ISC.Density functional theory(DFT)calculations further support the formation of excimers.DFT results indicate that 2 PDI-Th exhibits an H-typed molecular configuration which is beneficial to form the excimers,while fused-2 PDITh gives a twisted X-shaped configuration in the optimized ground and excited state.In steady-state emission spectra,2 PDI-Th shows abroad and featureless spectral characteristics of the excimers with a decay time of 840 ps,which is much shorter than those of PDI(5.5 ns)and fused-2 PDI-Th(3.3 ns).The triplet lifetime(67 ms)of fused-2 PDI-Th is factor of 3 longer than that of 2 PDI-Th(22 ms).These results demonstrate that ring-fused structure is an efficient strategy to eliminate excimer formation and prolong the lifetime of triplet excitons,which provides a new insight for design of optoelectronic molecules for high efficiency organic solar cells. 展开更多
关键词 Ultrafast relaxation dynamics Triplet excited state Exciton lifetime Photophysical process Organic solar cell
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Dual-comb soliton rains based on polarization multiplexing in a single-walled carbon nanotube mode-locked Er-doped fiber laser
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作者 赵悦 秦莹 +7 位作者 贾凯琳 陈丽 陈广伟 胡国庆 武腾飞 李慧宇 贺敬文 周哲海 《Chinese Optics Letters》 SCIE EI CAS CSCD 2024年第5期62-67,共6页
We experimentally demonstrate tunable dual-comb soliton rains in a polarization multiplexing fiber laser based on a singlewalled carbon nanotube.The repetition frequency difference of dual-comb pulses is about 39 Hz,w... We experimentally demonstrate tunable dual-comb soliton rains in a polarization multiplexing fiber laser based on a singlewalled carbon nanotube.The repetition frequency difference of dual-comb pulses is about 39 Hz,with a maximum extinction ratio of 29 dB.With suitable polarization states,one of the dual-comb pulses switches into soliton rain sequence with chirped isolating soliton trains.The signal-to-noise ratio reaches 61 dB,which is 11 dB higher than that of the normal dual-comb pulses.The intervals between chirped isolating solitons are distributed progressively,and the number of isolating solitons can be flexibly tuned from 2 to 11 by adjusting polarization state or pump power.Our work will provide support for further understanding of interaction dynamics of solitons and give a new route to the application of precision measurement. 展开更多
关键词 mode-locked fiber laser soliton rains dual-comb pulses gain relaxation dynamics single-walled carbon nanotube
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Correlation of cooperatively localized rearrangement on the "fluidized domain" in glass substances (or polymers) to their fragility Ⅲ:Theory of dynamic fragility at isochoric state
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作者 JIN Yan SONG MingShi +1 位作者 HU GuiXian WU DaMing 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第3期420-436,共17页
A set of universal equations on the reduced stress relaxation modulus with K-W-W stretched exponential function has been derived from the dynamics of α and β structural relaxation processes. In the present work, the... A set of universal equations on the reduced stress relaxation modulus with K-W-W stretched exponential function has been derived from the dynamics of α and β structural relaxation processes. In the present work, the K-W-W decay function is used to define the three types of relaxations (single α, single β relaxation and α-β co-relaxation), then their average times of relaxation are theoretically calculated from the reduced shear stress relaxation modulus and the relaxation time spectrum function H(τ). When the average time of co-relaxation, the reference temperatures (ficitive Tf and glass transition Tg) and the isostructural parameter achieved from the conditions of isostructural glass state are introduced into the reduced shear stress relaxation modulus (GT) under the equilibrium state, a set of correlations between isochoric fragility index (mvα, mvβ and mvαβ) and the coupling strength (α and β) under the reference temperatures are derived from the exact definition of isochoric fragility. So the theory of dynamic fragility for glass substances at isochoric state is developed. The theory can predict the following main features of structural relaxations and behavior of isochoric fragility: the temperature dependence of peak relaxation frequency exhibits a bifurcation with a pair of single α and single β relaxations; the temperature dependence of Stickel equation on 1/T exhibits two crossovers with VFTH(1) and VFTH(2) at the temperatures of Tf and Tg regime; there are two linear correlations between isochoric fragility index (mvα and mvβ) and the coupling strength. Fine agreements between the theoretical calculation and experimental results are obtained. 展开更多
关键词 isochoric fragility fluidized domain constituent chains &alpha and &beta relaxation dynamics of structural relaxation reduced stress relaxation modulus
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Structural relaxation and glass transition behavior of binary hard-ellipse mixtures
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作者 Liang Wang Baicheng Mei +2 位作者 Jianhui Song Yuyuan Lu Lijia An 《Science China Chemistry》 SCIE EI CAS CSCD 2018年第5期613-618,共6页
Structural relaxation and glass transition in binary hard-spherical particle mixtures have been reported to exhibit unusual features depending on the size disparity and composition. However, the mechanism by which the... Structural relaxation and glass transition in binary hard-spherical particle mixtures have been reported to exhibit unusual features depending on the size disparity and composition. However, the mechanism by which the mixing effects lead to these features and whether these features are universal for particles with anisotropic geometries remains unclear. Here, we employ event-driven molecular dynamics simulation to investigate the dynamical and structural properties of binary two-dimensional hard-ellipse mixtures. We find that the relaxation dynamics for translational degrees of freedom exhibit equivalent trends as those observed in binary hard-spherical mixtures. However, the glass transition densities for translational and rotational degrees of freedom present different dependencies on size disparity and composition. Furthermore,we propose a mechanism based on structural properties that explain the observed mixing effects and decoupling behavior between translational and rotational motions in binary hard-ellipse systems. 展开更多
关键词 binary ellipse mixture molecular dynamics simulation glass transition translational relaxation time rotational relaxation time
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Simulation of construction shape-forming process of cable domes 被引量:2
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作者 YE JiHong FENG RuoQiang KAN Yuan 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第1期101-116,共16页
A cable dome has no stiffness or load carrying capacity unless it has been prestressed.Analyses of cable domes are based on successful prestressing designs,making force finding analysis very important.A new force find... A cable dome has no stiffness or load carrying capacity unless it has been prestressed.Analyses of cable domes are based on successful prestressing designs,making force finding analysis very important.A new force finding method named the imbal-ance force iterative method is proposed,which can overcome some limitations of the integrity feasible prestressing method.For instance,even if groups are assigned by mistake,the pretension distribution that satisfies the known geometry form can also be found.This method possess good stability and calculation efficiency,and a case study indicates that it is applicable to the force finding of large and complicated cable domes.On the other hand,form finding analysis of cable domes is also a key engineering problem.However,rigid displacement occurs in this process,which makes the analysis more complex.In this pa-per,the dynamic relaxation method was selected,and the problem of rigid displacement was therefore effectively solved.The method includes two steps:first,the stretching cables are released,and secondly,an axial force is imposed on the two ends of each released cable.This method is convenient in its calculation and clear in its conception.A case study indicates that the method is suitable for the simulation of the construction process of various cable domes and cable-strut tension structures.Moreover,a form finding experiment was conducted on a model of a cable dome with a diameter of 4.8 m by tensing diagonal cables.The behavior of the model in the form finding process was investigated.The experimental results indicate that the ini-tial lengths of members and prestress loss are key issues in cable domes design.The results also prove that the methods of form finding and force finding proposed in this paper are reliable and effective. 展开更多
关键词 cable domes force control of construction process form control of construction process imbalance force iterativemethod dynamic relaxation method construction shape-forming process experiment
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Computation of Two-Phase Biomembranes with Phase Dependent Material Parameters Using Surface Finite Elements 被引量:1
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作者 Charles M.Elliott Björn Stinner 《Communications in Computational Physics》 SCIE 2013年第2期325-360,共36页
The shapes of vesicles formed by lipid bilayers with phase separation are governed by a bending energy with phase dependent material parameters together with a line energy associatedwith the phase interfaces.We presen... The shapes of vesicles formed by lipid bilayers with phase separation are governed by a bending energy with phase dependent material parameters together with a line energy associatedwith the phase interfaces.We present a numericalmethod to approximate solutions to the Euler-Lagrange equations featuring triangulated surfaces,isoparametric quadratic surface finite elements and the phase field approach for the phase separation.Furthermore,the method involves an iterative solution scheme that is based on a relaxation dynamics coupling a geometric evolution equation for the membrane surface with a surface Allen-Cahn equation.Remeshing and grid adaptivity are discussed,and in various simulations the influence of several physical parameters is investigated. 展开更多
关键词 BIOMEMBRANE surface finite elements relaxation dynamics
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Probing the formation of ultrastable metallic glass from structural heterogeneity
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作者 Qijing Sun DavidM Miskovic Michael Ferry 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第9期214-223,共10页
Ultrastable metallic glasses(SMGs)exhibit enhanced stability comparable to those of conventional glasses aged for thousands of years.The ability to understand why certain alloy compositions and processing conditions g... Ultrastable metallic glasses(SMGs)exhibit enhanced stability comparable to those of conventional glasses aged for thousands of years.The ability to understand why certain alloy compositions and processing conditions generate an SMG is an emerging challenge.Herein,amplitude-modulation dynamic atomic force microscopy was utilized for tracking the structure of Zr_(50)Cu_(50),Zr_(50)Cu_(44.5)Al_(5.5)and Zr_(50)Cu_(41.5)Al_(5.5)Mo_(3) thin film metallic glasses(TFMGs)that were produced by direct current magnetron sputtering at room temperature with the rate of deposition being the only variable.The transition in stability from bulkto SMG-like behavior resides in the change of relaxation mechanism as the deposition rate is decreased.The formation of SMGs is directly linked with the degree of structural heterogeneity,whereby MGs with greater heterogeneity have a higher potential to form SMGs with more significant enhancement in stability.Slower deposition rates,however,are required to yield the more homogenous structure and lower energy state underlying the ultrastability.Ultrastability is closely linked with the geometric shape and distribution of loosely packed phases,whereby SMGs containing more slender loosely packed phases with a more skewed distribution achieve more significant improvements in stability.This work not only provides direct evidence of the structure of SMGs,but also opens new horizons for the design of SMGs. 展开更多
关键词 Ultrastable metallic glass Structural heterogeneity relaxation dynamics Amplitude-modulation dynamic atomic force microscopy
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