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623篇 您的检索式:作者名="structural"
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1Recent development in structural design and optimization显示文摘With the fast development of computational mechanics and the capacity as well as the speed of modern computers,simulation-based structural optimization has become an indispensable tool in the design process of competitive products.This paper presents a brief description of the current status of structural optimization by reviewing some significant progress made in the last decades.Potential research topics are also discussed.The entire literatures of the field are not covered due to the limitation of the length of paper.The scope of this review is limited and closely related to the authors' own research interests.Xu Guo·Geng-Dong Cheng State Key Laboratory of Structural Analysis for Industrial Equipment,Department of Engineering Mechanics,Dalian University of Technology, Dalian 116023,China 2010Acta Mechanica Sinica2010,26,6:42
2Modelling of multi-bodies in close proximity under water waves——Fluid resonance in narrow gaps显示文摘Viscous fluid model and potential flow model with and without artificial damping force(f=-μV,μ the damping coefficient and V the local averaging flow velocity) are employed in this work to investigate the phenomenon of fluid resonance in narrow gaps between multi-bodies in close proximity under water waves.The numerical results are compared with experimental data available in the literature.The comparison demonstrates that both the viscous fluid model and the potential flow model are able to predict the resonant frequency reasonably well.However the conventional potential flow model(without artificial damping term) significantly over-predicts the wave height in narrow gaps around the resonant frequency.In order to calibrate the appropriate damping coefficient used for the potential model and make it work as well as the viscous fluid model in predicting the resonant wave height in narrow gaps but with little computational efforts,the dependence of damping coefficient μ on the body geometric dimensions is examined considering the parameters of gap width Bg,body draft D,body breadth ratio Br and body number n(n = 2,3),where Br = BB/BA for the case of two bodies(Body A and Body B) with different breadths of BA and BB,respectively.It was confirmed that the damping coefficient used for the potential flow model is not sensitive to the geometric dimensions and spatial arrangement.It was found that μ∈ [0.4,0.5] may guarantee the variation of Hg/H0 with kh to be generally in good agreement with the experimental data and the results of viscous fluid model,where Hg is the excited wave height in narrow gaps under various dimensionless incident wave frequencies kh,H0 is the incident wave height,k = 2π/L is the wave number and h is the water depth.LU Lin1,2,TENG Bin3,CHENG Liang 4,SUN Liang5 & CHEN XiaoBo6 1 Center for Deepwater Engineering,Dalian University of Technology,Dalian 116024,China 2 State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,Dalian 116024,China 3 State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China 4 School of Civil and Resource Engineering,The University of Western Australia,Crawly 6003,Australia 5 Centre for Offshore Research and Engineering,Department of Civil Engineering,National University of Singapore,117576,Singapore 6 Research Department,Bureau Veritas,Neuilly-Sur-Seine,92570,France 2011Science China(Physics,Mechanics & Astronomy)2011,54,1:29
3Study on real working performance and overload safety factor of high arch dam显示文摘Considering the fact that high arch dams have problems such as complicated stress,high cost,and hazards after being damaged,this paper intends to study the effects of load,material strength,and safety analysis method on dam safety and working performance of arch dams.In this article,the effects of temperature,self weight exaction way and water loading on structure response are first discussed,and a more reasonable way of considering is then put forward.By taking into consideration the mechanical property of materials and comparing the effects of different yield criteria on overloading safety of high arch dams,this paper concludes that brittle characteristics of concrete should be fully considered when conducting safety assessment for high arch dams to avoid overestimating the bearing capacity of the dams.By comparing several typical projects,this paper works out a safety assessment system of multiple safety and relevant engineering analogical analysis methods,which is closer to the actual situation,and thus is able to assess the response of high arch dam structure in a more comprehensive way,elicit the safety coefficients in different situations,and provide a new way of considering the safety assessment of high arch dams.ZHANG GuoXin,LIU Yi & ZHOU QiuJing Department of Structures and Materials,China Institute of Water Resources and Hydropower Research,Beijing 100038,China 2008Science China(Technological Sciences)2008,51,S2:25
4Numerical simulations of self-propelled swimming of 3D bionic fish school显示文摘Numerical simulations of self-propelled swimming of a three dimensional bionic fish and fish school in a viscous fluid are carried out. This is done with the assistance of a parallel software package produced for 3D moving boundary problems. This computational fluid dynamics package combines the adaptive multi-grid finite volume method, the immersed boundary method and VOF (volume of fluid) method. By using the package results of the self-propelled swimming of a 3D bionic fish and fish school in a vis- cous fluid are obtained. With comparison to the existing experimental measurements of living fishes, the predicted structure of vortical wakes is in good agreement with the measurements.WU ChuiJie1 & WANG Liang2 1 State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China 2 Research Center for Fluid Dynamics, People’s Liberation Army University of Science and Technology, Nanjing 211101, China 2009Science China(Technological Sciences)2009,52,3:23
5NUMERICAL MODELLING OF ROCK FALL USING EXTENDED DDA显示文摘The reasonable design of protective structures to mitigate the hazards from rock fall depends on the knowledge of motion behaviors of falling stones,such as the falling paths,velocities,jump heights and distances.Numerical simulation is an effective way to gain such kind of knowledge,In this paper,the discontinuous deformation analysis (DDA) is applied to rock fall analysis.In order to obtain more reliable results,the following improvements and extensions are made on the original DDA.(1)Solve the problem of block expansions due to rigid body rotation error.(2) Add the function of modeling the drag resistance from air and plants so that the velocities of falling stones obtained by simulations are good enough in agreement with those by experiments in situ.(3)Add the capability to consider energy loss due to block collisions so that the jumping heights and distances obtained by simulations are good enough in agreement with thos by experiments even for the slope with very soft layer on its surface.One of application examples is presented to show that the extended DDA is very effective and useful in rock fall analysis.Therefore,the presented method is expected to be put into wide use in slop stability analysis.Chen Guangqi (Graduate School of Civil and Structural Engineering, Kyushu University, Fukuoka 816-8581 Japan) 2003岩石力学与工程学报2003,22,6:14
6Effects of Current Frequency on the Microstructure and Wear Resistance of Ceramic Coatings Embedded with SiC Nano-particles Produced by Micro-arc Oxidation on AZ91D Magnesium Alloy显示文摘To improve the surface wear resistance of the ceramic coating fabricated by micro-arc oxidation (MAO) on AZ91D magnesium alloy,ceramic coatings embedded with SiC nano-particles at different current frequency (500 Hz,700 Hz,and 900 Hz) were produced during the MAO process.The morphology and phase composition of the coatings were investigated by scanning electron microscopy (SEM),field emission scanning electron microscopy (FESEM),and X-ray diffraction (XRD).The surface roughness of the coatings was characterized by confocal laser scanning microscopy (CLSM).Simultaneously,the tribological properties of the composite coatings were evaluated by using a universal materials tester (UMT).The results shows that the wear resistance of the ceramic coatings with SiC nano-particles was improved significantly compared to the ceramic coatings without SiC nano-particles.Furthermore,the composite coating formed at current frequency 900 Hz showed the better wear resistance than the others.Yue Yang and Hua Wu Key Laboratory of Advanced Structural Materials,Ministry of Education,Changchun University of Technology,Changchun 130012,China 2010Journal of Materials Science & Technology2010,26,10:14
7Assembly and structure of protein phosphatase 2A显示文摘Protein phosphatase 2A (PP2A) represents a conserved family of important protein serine/threonine phosphatases in species ranging from yeast to human. The PP2A core enzyme comprises a scaffold subunit and a catalytic subunit. The heterotrimeric PP2A holoenzyme consists of the core enzyme and a variable regulatory subunit. The catalytic subunit of PP2A is subject to reversible methylation, medi-ated by two conserved enzymes. Both the PP2A core and holoenzymes are regulated through interac-tion with a large number of cellular cofactors. Recent biochemical and structural investigation reveals critical insights into the assembly and function of the PP2A core enzyme as well as two families of holoenzyme. This review focuses on the molecular mechanisms revealed by these latest advances.SHI Yi Gong Center for Structural Biology, Department of Biological Sciences and Biotechnology, and School of Medicine, Tsinghua University, Beijing 100084, China 2009Science China(Life Sciences)2009,52,2:13
8Gradual solution heat treatment of AlSiCuMg cast alloys显示文摘The microstmcture characteristics of AlSiCuMg cast alloys were studied with different Cu content and the gradual solution treatment by DSC, SEM, TEM and mechanical method. The melting point of α(Al) + Si decreases and polynary eutectic phases with low melting point form with increase of Cu content. Gradual solution treatment includes two steps:solution treating near the melting point of polynary eutectic phase to take it dissolve first, and then increasing solution temperature to take the remainder copper intermetallics dissolved into o(Al). Grain boundaries melting can be avoided by gradual solution treatment, even the maximum solution temperature is above final solidification point, and the age hardening response increases correspondingly.WANG Guiqing , BIAN Xiufang ,and ZHANG Junyan1) The Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061, China2) Department of Material Science and Technology, Shandong Architectural Engineering Institute, Jinan 250014, China 2003Rare Metals2003,22,4:13
9我国大陆2009年底已建成180m以上高层建筑统计显示文摘Council on Tall Buildings,Structural Branch,Architectural Society of China 2010土木工程学报2010,43,5:12
10Structural condition assessment of long-span suspension bridges using long-term monitoring data显示文摘这份报纸集中于用监视系统的结构的健康测量的长期的监视数据开发一种联机结构的条件评价技术。为 Runyang 暂停桥的频率温度和横梁结束排水量温度的季节的关联首先被执行。然后,用一个六顺序的多项式的一种统计建模技术进一步被使用提出频率温度和排水量温度,测量频率和排水量的反常变化用吝啬的价值控制图表从被检测的关联。分析结果证明更高的颤动模式和排水量的形式的频率与环境温度和建议方法展览有显著季节的关联为检测形式的频率和排水量的微导致损坏的变化的一个好能力。结果证明建议方法能有效地从频率和排水量时间系列消除温度复杂并发症并且很好适合长跨度的暂停桥监视的联机状况。监视的关键词结构的健康 - 形式的频率 - 横梁结束排水量 - 温度 - 季节的关联 - 暂停桥牌旁边支持了:在资助号码下面的中国的国家自然科学基础 50725828 与号码 50808041;不到资助号码 200802861011 的中国的教育部的博士节目基础;东南大学在下面的研究生院的科学研究基础资助没有。Deng Yang~+,Ding Youliang~(++) and Li Aiqun~§Key Laboratory of Concrete & Prestressed Concrete Structures of Ministry of Education,Southeast University,Nanjing 210096,China PhD Student ++ Assistant Professor ~§Professor 2010Earthquake Engineering and Engineering Vibration2010,9,1:12
11An adaptive version of ghost-cell immersed boundary method for incompressible flows with complex stationary and moving boundaries显示文摘An adaptive version of immersed boundary method for simulating flows with complex stationary and moving boundaries is presented.The method employs a ghost-cell methodology which allows for a sharp representation of the immersed boundary.To simplify the implementation of the methodology,a volume-of-fluid method is introduced to identify the immersed boundary.In addition,the domain is spatially discretized using a tree-based discretization which is relatively simple to implement a fully flexible adaptive refinement strategy.Finally,the methodology is validated by comparing it with numerical and experimental results on three cases:(1) the flow passing a circular cylinder at Re=40 and Re=100,(2) a periodic oscillation of a circular cylinder in fluid at rest and(3) the self-propelled fish-like swimming at Re=6400.WANG Liang1 & WU ChuiJie2,3 1 School of Science,PLA University of Science and Technology,Nanjing 211101,China 2 State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,Dalian 116024,China 3 School of Aeronautics and Astronautics,Dalian University of Technology,Dalian 116024,China 2010Science China(Physics,Mechanics & Astronomy)2010,53,5:11
12Thermoelastic properties of sandwich materials with pin-reinforced foam cores显示文摘Pin-reinforced foam is a novel type of sandwich core materials formed by inserting pins(trusses) into a foam matrix to create a truss-like network reinforced foam core.Upon loading,the pins deform predominantly by local stretching whilst the deformation of foam is governed by local bending.This paper presents a theoretical study on the thermoelasticity of pin-reinforced foam sandwich cores.To calculate the effective thermoelastic properties of pin-reinforced foam cores,the energy-based homogenization approach is employed to develop a micromechanics-based model,calibrated by the existing experimental data.It is found that the stiffness of the sandwich core is mainly governed by pin reinforcements:the foam matrix contributes little to sandwich stiffness.Compared with traditional foam cores without pin reinforcements,the changes in inplane thermal expansion coefficients are not vigorous as a result of pin reinforcements,while the through-thickness thermal expansion coefficient changes significantly.It is also demonstrated that it is possible to design materials with zero or negative thermal expansion coefficients under such a context.LU TianJian1,LIU Tao2,3 & DENG ZiChen2,4 1 MOE Key Laboratory of Strength and Vibration,School of Aerospace,Xi’an Jiaotong University,Xi’an 710049,China 2 Department of Engineering Mechanics,Northwestern Polytechnical University,Xi’an 710072,China 3 Department of Engineering,University of Cambridge,Cambridge CB2 1PZ,UK 4 State Key Laboratory of Structural Analysis of Industrial Equipment,Dalian University of Technology,Dalian 116024,China 2008Science China(Technological Sciences)2008,51,12:10
13Mobile Ubiquitous Service Environment显示文摘The Mobile Ubiquitous Service Environment (MUSE),established through the coordination and integration of mobile telecommunications and ubiquitous network,in the pursuit of Always Best Experience (ABE),represents the major development trend for the next generation mobile wireless network. Research on MUSE will involve the integration of the computing model system,service platform system,operating system and terminal structure system,all of which involve exploration and innovation of a new networking structure,its control and management as well as way of measuring. The change in network resources triggers the change in network computing models. To let readers have a basic understanding of MUSE,this lecture introduces it in four sections. This section focuses on the development and demand analysis of the service platform.Zhang Ping,Ji Yang,Feng Zhiyong (Research Center for Wireless New Technology,Beijing University of Posts and Telecommunications,Beijing 100876,China) The Mobile Ubiquitous Service Environment (MUSE),established through the coordination and integration of mobile telecommunications and ubiquitous network,in the pursuit of Always Best Experience (ABE),represents the major development trend for the next generation mobile wireless network. Research on MUSE will involve the integration of the computing model system,service platform system,operating system and terminal structure system,all of which involve exploration and innovation of a new networking structure,its control and management as well as way of measuring. The change in network resources triggers the change in network computing models. To let readers have a basic understanding of MUSE,this lecture introduces it in four sections. This section focuses on the development and demand analysis of the service platform. 2007ZTE Communications2007,5,2:10
14Study on correlations of modal frequencies and environmental factors for a suspension bridge based on improved neural networks显示文摘By using of long-term monitoring data of Runyang Suspension Bridge,the improved back-propagation neural networks (BPNNs) are formulated for modeling the correlations between modal frequencies and environmental conditions including wind,temperature and vehicle load.Then,with the correlation models the environmental effects on modal frequencies are quantified and the abnormal changes of measured frequencies are detected by means of the hypothesis tests.Analysis results reveal that BPNN-based correlation models improved by both early stopping and Bayesian regularization techniques exhibit excellent generalization capability.And the developed correlation models can effectively reduce the environmental variability in modal frequencies.The t-test method provides a good capability to detect the damage-induced 0.16% and 0.12% abnormal changes of the 5th and 6th modal frequencies,respectively.Hence,the proposed method is suitable for real-time monitoring of suspension bridge conditions.DING YouLiang,DENG Yang & LI AiQun Key Laboratory of Concrete and Prestressed Concrete Structure of Ministry of Education,Southeast University,Nanjing 210096,China 2010Science China(Technological Sciences)2010,53,9:9
15New Developments in Structural Health Monitoring Based on Diagnostic Lamb Wave显示文摘Structure health monitoring based on diagnostic Lamb waves has been found to be one of the most promising techniques recently. This paper has a brief review of the new developments on this method including the basic novel of the method, fundamentals and mathematics of Lamb wave propagation, narrowband and wideband Lamb wave excitation methods, optimization of excitation factors and diagnostic Lamb wave interpretation methods.Shenfang YUAN, Yingdi XU and Ge PENGThe Smart Materials & Structures Aeronautic Key Laboratory, Nanjing University of Aeronautic and Astronautic, Nanjing 210016, China 2004Journal of Materials Science & Technology2004,20,5:9
16Solidification Simulation of Investment Castings of Single Crystal Hollow Turbine Blade显示文摘The three-dimensional solidification simulation of the investment castings of single crystal hollow turbine blade at the withdrawal rates of 2 mm/min, 4.5 mm/min and 7 mm/min has been performed with the finite element thermal analysis. The calculated results are in accordance with the experimental ones. The results show that with the increase of withdrawal rate the concave curvature of the liquidus isotherm is larger and larger, and the temperature gradients of the blades increase. No effects of withdrawal rate on the distribution of the temperature gradients of the starter and helical grain selector of the blades are observed at withdrawal rates of 2 mm/min, 4.5 mm/min and 7 mm/min. The relatively high temperature gradient between 500℃/cm and 1000℃/cm in the starter and helical grain selector is obtained at three withdrawal rates.Jiarong LI, Shizhong LIU, Hailong YUAN and Zhengang ZHONGNational Key Laboratory of Advanced High Temperature Structural Materials, Beijing Institute of Aeronautical Materials, Beijing 100095, China 2003Journal of Materials Science & Technology2003,19,6:9
17Stiffness requirement of flexible skin for variable trailing-edge camber wing显示文摘The method for analyzing the deformation of flexible skin under the air loads was developed based on the panel method and finite element method.The deformation of flexible skin under air pressures and effects of the local deformation on the aerodynamic characteristics were discussed.Numerical results show that the flexible skin on the upper surface of trailing-edge will bubble under the air loads and the bubble has a powerful effect on the aerodynamic pressure near the surface of local deforma-tion.Then the stiffness requirements for flexible skin of variable trailing-edge were given by using the Jacobs rule,i.e.,the maximum displacement of skin is not greater than 0.1% of wing chord.Results show that the in-plane stiffness can be reduced by increasing the ratio of bending stiffness to in-plane stiffness.Although the deformation of flexible skin increases with the in-plane stiffness decreasing,it depends on the bending stiffness.When the bending stiffness exceeds critical value,the deformation of flexible skin only depends on the bending stiffness and has nothing to do with the in-plane stiffness.The conclusions can be used for the structural design of flexible skin.YIN WeiLong Center for Composite Materials and Structures and Postdoctoral Station of Mechanics,Harbin Institute of Technology,Harbin 150080,China 2010Science China(Technological Sciences)2010,53,4:9
18Spectroscopic evidence for triplet excitation energy transfer among carotenoids in the LH2 complex from photosynthetic bacterium Rhodopseudomonas palustris显示文摘The LH2 complex from Rhodopsudomonas (Rps.) palustris is unique in the heterogeneous carotenoid compositions. The dynamics of triplet excited state Carotenoids (3Car*) has been investigated by means of sub-microsecond time-resolved absorption spectroscopy both at physiological temperature (295 K) and at cryogenic temperature (77 K). Broad and asymmetric Tn←T1 transient absorption was observed at room temperature following the photo-excitation of Car at 532 nm, which suggests the contribution from various carotenoid compositions having different numbers of conjugated C=C double bonds (NC=C). The triplet absorption bands of different carotenoids, which superimposed at room temperature, could be clearly distinguished upon decreasing the temperature down to 77 K. At room temperature the shorter-wavelength side of the main Tn←T1 absorption band decayed rapidly to reach a spectral equilibration with a characteristic time constant of~1 μs, the same spectral dynamics, however, was not observed at 77 K. The aforementioned spectral dynamics can be explained in terms of the triplet-excitation transfer among heterogeneous carotenoid compositions. Global spectral analysis was applied to the time-resolved spectra at room temperature, which revealed two spectral components peaked at 545 and 565 nm, and assignable to the Tn←T1 absorption of Cars with NC=C=11 and NC=C=13, respectively. Surprisingly, the decay time constant of a shorter-con- jugated Car, I.e. 0.72 μs (aerobic) and 1.36 μs (anaerobic), is smaller than that of a longer-con- jugated Car, I.e. 2.12 μs (aerobic) and 3.75 μs (anaerobic), which is contradictory to the general rule of carotenoids and relative polyenes. The results are explained in terms of triplet-excitation transfer among different types of Cars. It is postulated that two Cars with different conjugation lengths coexist in an α,β-subunit in the LH2 complex.FENG Juan, WANG Qian, ZHANG Xujia, HUANG Youguo, Al Xicheng, ZHANG Xingkang & ZHANG JianpingState Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China 2004Science China Chemistry2004,47,1:8
19Cellulose conversion to polyols on supported Ru catalysts in aqueous basic solution显示文摘It is of great significance and challenge to achieve direct conversion of cellulose to specific polyols,e.g.,ethylene glycol and propylene glycol.For such selective conversion,a novel one-pot approach was studied by combination of alkaline hydrolysis and hydrogenation on supported Ru catalysts.A wide range of bases including solid bases,e.g.,Ca(OH)2 and La2O3,and phosphate buffers were examined in the cellulose reaction in water,and the cellulose conversions and polyol products depended largely on the basicity or pH values in the aqueous solutions.Ethylene glycol,1,2-propanediol,and especially 1,2,5-pentanetriol were obtained with selectivities of 15%,14% and 22%,respectively,at 38% cellulose conversion at pH 8 in phosphate buffer solution.These preliminary results provide potentials for efficient conversion of cellulose to targeted polyols by using the advantages of bases.DENG TianYin,SUN JiYing & LIU HaiChao Beijing National Laboratory for Molecular Sciences,State Key Laboratory for Structural Chemistry of Stable and Unstable Species Green Chemistry Center,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China 2010Science China Chemistry2010,53,7:8
20Structural Performance Evaluation Procedure for Large Flexible Airship of HALE Stratospheric Platform Conception显示文摘Basic loads applied on the airship envelope were analyzed.The resultant forces,the static bending moment and the dynamic bending moment were formulated.Based on classic linear elastic membrane theory,the procedures to calculate the minimum pressure were proposed for sufficient rigidity evaluation.The limit load capacity was further investigated,and the related formula were developed.Finally,the stress and internal forces analysis was carried out for cylindrical and non-cylindrical approximations of envelope hull of airship.The present research is very valuable to the overall preliminary design of airship and further research.陈务军 肖微微 Bernd Krplin Andreas KunzeInst.of Static and Dynamic for Aerospace Structures Univ.of Stuttgart Germany 2007Journal of Shanghai Jiaotong university(Science)2007,12,2:8
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