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A study on bearing characteristic and failure mechanism of thin-walled structure of a prefabricated subway

Lianjin TAO; Cheng SHI; Peng DING; Sicheng LI; Shang WU; Yan BAO

《结构与土木工程前沿(英文)》 2022年 第16卷 第3期   页码 359-377 doi: 10.1007/s11709-022-0816-2

摘要: In order to study the bearing performance of a new type of prefabricated subway station structure (PSSS), firstly, a three-dimensional finite element model of the PSSS was established to study the nonlinear mechanics and deformation performance. Secondly, the bearing mechanism of a PSSS was investigated in detail. Finally, the development law of damages to a thin-walled prefabricated component and the failure evolution mechanism of a PSSS were discussed. The results showed that this new type of the PSSS had good bearing capacity. The top arch structure was a three-hinged arch bearing system, and the enclosure structure and the substructure were respectively used as the horizontal and vertical support systems of the three-hinged arch structure to ensure the integrity and stability of the overall structure. Moreover, the tongue-and-groove joints could effectively transmit the internal force between the components and keep the components deformed in harmony. The rigidity degradation of the PSSS caused by the accumulation of damages to the spandrel, hance, arch foot, and enclosure structure was the main reason of its loss of bearing capacity. The existing thin-walled components design had significant advantages in weight reduction, concrete temperature control, components hoisting, transportation and assembly construction, which achieved a good balance between safety, usability and economy.

关键词: prefabricated subway station     thin-walled components     finite element analysis     bearing characteristic     failure mechanism    

One DOF mechanism for the mechanical harvest of vines in an arbor structure and the validation of the

Osvaldo PENISI,José BOCCA,Horacio AGUILAR,Pedro BOCCA

《机械工程前沿(英文)》 2015年 第10卷 第3期   页码 221-232 doi: 10.1007/s11465-015-0347-9

摘要:

In the mechanized harvest of vines, grape berries are detached through the vibration to the structure supporting the clusters. According to the kind of guide selected, the clusters require one or two vibration directions in the structure. For guiding in parral structures, vibration is necessary in two directions or planes: One perpendicular to the other. The guide branches producing the clusters develop in these planes, and the guiding is called H-guiding. Mechanism theory indicates that a mechanism has as many degrees of freedom as its actuators, and an actuator is needed to achieve a certain vibration. Having the smallest number of possible actuators is beneficial in reducing moving parts and achieving more compact and easily controllable mecha-nisms. In this case, a single degree-of-freedom mechanism is proposed. It is capable of generating vibrations on two planes: One perpendicular to the other. This mechanism is the sum of two link mechanisms on perpendicular planes with a common outlet located at the output rod of the mechanism where the actuator is found. As the distance between the soil and the elements containing the clusters is not constant, a system has been designed to measure the accelerations at the bars and the rocker to validate the acceleration values that detach the grape berries in a prototype in a lab experiment, to ensure that the acceleration needed for pulling the grape berries are produced at any contact point of the bar.

关键词: harvest     mechanisms     one DOF     vibration    

Structural synthesis of ancient Chinese foot-operated silk-reeling mechanism

Kuohung HSIAO, Yuhsun CHEN, Hongsen YAN,

《机械工程前沿(英文)》 2010年 第5卷 第3期   页码 279-288 doi: 10.1007/s11465-010-0101-2

摘要: This work synthesizes the structures of the foot-operated silk-reeling mechanism, which was vaguely depicted in many literatures in ancient China. Based on the analysis of the mechanism, the structural characteristics and design constraints of the mechanism with indeterminate links and joints are concluded. Then, according to the concepts of generalization and specialization subject to the concluded design constraints, all feasible structures of the mechanism that met the technological standards of the subject’s time period are reconstructed. This reconstruction process provides a logical foundation to better understanding, clarification, and suggestions for the issue of ancient mechanical drawings with indeterminate links and joints.

关键词: silk-reeling mechanism     structure of mechanism     reconstruction design     history of machinery    

VITHM1 mediated green synthesis of silver nanoparticles: Mechanism and biological applications

Mani Abirami, Krishnan Kannabiran

《化学科学与工程前沿(英文)》 2016年 第10卷 第4期   页码 542-551 doi: 10.1007/s11705-016-1599-6

摘要: We present the microbial green synthesis of silver nanoparticles (NPs) by VITHM1 strain (MTCC No. 12465). The secondary metabolites in the cell free supernatant of this bacterium when incubated with 1 mmol/L AgNO , mediated the biological synthesis of AgNPs. The synthesized AgNPs were characterized by UV-visible spectrum, X-ray diffraction (XRD), atomic force microscope, scanning electron microscopy equipped with energy dispersive spectroscopy, transmission electron microscopy, FT-IR spectroscopy, dynamic light scattering and zeta potential. They were highly stable and, spherical in shape with the average size of 30?50 nm. The secondary metabolites involved in the formation of AgNPs were identified gas chromatography-mass spectrography. The 3D structure of the unit cell of the synthesized AgNPs was determined using XRD data base. The synthesized AgNPs exhibited significant antibacterial activity against tested bacterial pathogens, and did not show haemolysis on human red blood cells. This green synthesis could provide a new platform to explore and use AgNPs as antibacterial therapeutic agents.

关键词: Streptomyces ghanaensis VITHM1     nanoparticles     3D structure     antibacterial activity    

Progressive collapse of 2D reinforced concrete structures under sudden column removal

El Houcine MOURID, Said MAMOURI, Adnan IBRAHIMBEGOVIC

《结构与土木工程前沿(英文)》 2020年 第14卷 第6期   页码 1387-1402 doi: 10.1007/s11709-020-0645-0

摘要: Once a column in building is removed due to gas explosion, vehicle impact, terrorist attack, earthquake or any natural disaster, the loading supported by removed column transfers to neighboring structural elements. If these elements are unable to resist the supplementary loading, they continue to fail, which leads to progressive collapse of building. In this paper, an efficient strategy to model and simulate the progressive collapse of multi-story reinforced concrete structure under sudden column removal is presented. The strategy is subdivided into several connected steps including failure mechanism creation, MBS dynamic analysis and dynamic contact simulation, the latter is solved by using conserving/decaying scheme to handle the stiff nonlinear dynamic equations. The effect of gravity loads, structure-ground contact, and structure-structure contact are accounted for as well. The main novelty in this study consists in the introduction of failure function, and the proper manner to control the mechanism creation of a frame until its total failure. Moreover, this contribution pertains to a very thorough investigation of progressive collapse of the structure under sudden column removal. The proposed methodology is applied to a six-story frame, and many different progressive collapse scenarios are investigated. The results illustrate the efficiency of the proposed strategy.

关键词: failure mechanism     MBS dynamic analysis     gravity loads     structure-ground contact     structure-structure contact     energy conserving/decaying scheme    

KDD中双库协同机制的研究(Ⅰ)

杨炳儒,王建新

《中国工程科学》 2002年 第4卷 第4期   页码 41-51

摘要:

针对KDD(基于数据库的知识发现)主流发展中存在的典型问题提出了用知识库去 制约与驱动数据库, 并通过数据库改善知识库结构的知识发现的新思想,形成了具有双库协同机制的KDD的开放系统KDD*,从而提高了知识发现的速度、精度和认知自主性,并使知识库在结构上具备了实时维护与自我进化的能力,同时阐述了作为双库协同基础的数据库和知识库在本质上的对应关系。

关键词: 知识结点     本原知识库     本原数据库     数据子类结构     双库协同机制    

Preparation of nZVI embedded modified mesoporous carbon for catalytic persulfate to degradation of reactive black 5

《环境科学与工程前沿(英文)》 2021年 第15卷 第5期 doi: 10.1007/s11783-020-1372-4

摘要:

• The MCNZVI is prepared as an interesting material for PS activation.

关键词: MCNZVI     Core-shell structure     Reactive Black 5     Persulfate     Mechanism    

Ribozyme and the mechanisms that underlie RNA catalysis

Timothy J. Wilson,Yijin Liu,David M. J. Lilley

《化学科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 178-185 doi: 10.1007/s11705-016-1558-2

摘要: Ribozymes are widespread, and catalyze some extremely important reactions in the cell. Mechanistically most fall into one of two classes, using either metal ions or general acid-base catalysis. The nucleolytic ribozymes fall into the latter class, mostly using nucleobases. A sub-set of these use a combination of guanine base plus adenine acid to catalyze the cleavage reaction. New ribozymes are still being discovered at regular intervals and we can speculate on the potential existence of ribozymes that catalyze chemistry beyond phosphoryl transfer reactions, perhaps using small-molecule coenzymes.

关键词: RNA catalysis     RNA structure     catalytic mechanism    

朝鲜半岛构造系统地质环境演化及动力学机制的地球卫星遥感影像解译研究

胡东生,张华京,徐冰,田新洪,张国伟

《中国工程科学》 2007年 第9卷 第12期   页码 31-38

摘要: 采用将东亚地区综合资料分析成果与地球卫星遥感影像解译相结合的方法,深入研究了全球构造域中典型的构造地段朝鲜地块。详细识别出朝鲜半岛地区的基本构造形式,其基本类型主要有环形构造(及辐射构造)、追踪构造、共轭构造、菱形构造、多米诺构造等;对其构造地质环境演化过程及地球动力学机制进行了宏观阐述, 晚古生代之前朝鲜半岛是由中国东部三个不同板块(华北板块、扬子板块、华南板块)贴拼焊接而成,中生代隆起成陆以后遭受了三期构造运动的影响(松林运动、大宝运动、佛国寺运动),新生代发生了玉岭运动。朝鲜地块基本构造形式的形成受

关键词: 地球卫星遥感影像解译;构造系统基本类型;地质环境演化过程;地球动力学机制;朝鲜半岛    

Static behavior of planar intersecting CFST connection in diagrid structure

Ling LI, Xianzhong ZHAO, Ke KE

《结构与土木工程前沿(英文)》 2011年 第5卷 第3期   页码 355-365 doi: 10.1007/s11709-011-0125-7

摘要: Intersecting connection plays an important role in the new diagrid structural system for high-rise buildings. To investigate the static behavior of the intersecting connection of concrete-filled steel tubular (CFST) columns, a typical reduced-scale planner connection specimen is tested under monotonic axial compression. The failure modes, force mechanism and bearing capacity of intersecting CFST connections are analyzed further in the follow-up numerical simulation, considering influences of intersecting angle, elliptical plate and ring plate. Test and simulation results prove that, intersecting connection can develop fully plastic deformation and provide sufficient bearing capacity. Parametric analysis indicates that bearing capacity of planar intersecting CFST connection mainly depends on intersecting angle and thickness of elliptical plate, while the ring plate affects that little. Capacity estimation method for planar intersecting CFST connection is proposed basing on the capacity of the critical section which is located near intersecting center for a distance of steel tube radius, and the design suggestions is provided in the end of this paper.

关键词: diagrid structure     concrete-filled steel tube     planar intersecting connection     experimental research     mechanism analysis    

Study on the growth of platinum nanowires as cathode catalysts in proton exchange membrane fuel cells

Ruiqing Wang, Xiaolan Cao, Sheng Sui, Bing Li, Qingfeng Li

《化学科学与工程前沿(英文)》 2022年 第16卷 第3期   页码 364-375 doi: 10.1007/s11705-021-2052-z

摘要: The platinum nanowires have been verified to be a promising catalyst to promote the performance of proton exchange membrane fuel cells. In this paper, accurately controlled growth of nanowires in a carbon matrix is achieved for reducing Pt loading. The effects of formic acid concentration and reaction temperature on the morphology and size of the Pt nanowires, as well as their electrochemical performances in a single cell, are investigated. The results showed that the increase in the formic acid concentration results in a volcano trend with the length of Pt nanowires. With increasing reduction temperature, the diameter of Pt nanowires increases while Pt particles evolve from one-dimensional to zero-dimensional up to 40 °C. A mechanism of the Pt nanowires growth is proposed. The optimized Pt nanowires electrode exhibits a power density (based on electrochemical active surface area) 79% higher than conventional Pt/C one. The control strategy obtained contributes to the design and control of novel nanostructures in nano-synthesis and catalyst applications.

关键词: Pt nanowires     morphology     structure control     in situ growth mechanism     proton exchange membrane fuel cells    

淀粉基API胶合木胶接结构破坏模式及失效机理

时君友,徐文彪,王淑敏

《中国工程科学》 2014年 第16卷 第4期   页码 40-44

摘要:

以淀粉基水性高分子异氰酸酯(API)胶合木胶接结构为研究对象,以胶接的压缩剪切强度为评估指标,通过加速湿热老化试验对胶接结构的破坏模式和失效机理进行了研究。结果表明:胶接结构的断裂性质为韧性断裂,且随着老化时间的增加,其破坏模式为由内聚破坏向内聚破坏+界面破坏转变。在湿热老化试验前期温度对压缩剪切试样性能起主要作用,在老化后期湿度起主要作用。

关键词: 胶接结构     加速湿热老化     断裂性质     破坏模式    

正交叠层机织布整体穿刺工艺的纤维弯曲伸长机理

朱建勋,何建敏,王海燕

《中国工程科学》 2003年 第5卷 第5期   页码 59-62

摘要:

分析了正交叠层机织布整体穿刺工艺机织布与钢针的相互作用,提出并建立了纤维的弯曲伸长及伸长断裂模式,讨论了影响纤维弯曲伸长的结构参数。通过理论分析和试验结果说明,绕针弯曲伸长断裂是Z向钢针直径和Z向距比值X的函数,为减少整体穿刺的纤维伸长断裂应选取较小的X比值。

关键词: 整体穿刺     纤维     弯曲伸长     结构参数     伸长断裂    

Theory and method of mechanism system design

Huijun ZOU, Qinghua LIANG, Qing ZHANG

《机械工程前沿(英文)》 2010年 第5卷 第4期   页码 399-411 doi: 10.1007/s11465-010-0116-8

摘要: Conceptual design is the most critical and creative phase of design. Recently, increasing attention has been directed to supporting conceptual-level computer aided creative design and its theories and methodologies. Specifically, for conceptual design of mechanical products, this paper presents a novel function solving model for mechanical product design and highlights the importance of systematic synthesis to achieve creative design. Then it builds a framework as a function-effect-process-action- mechanisms (FEPAM) mapping process, which enables creative design on the basis of conceiving different action schemes. After that, several key points are elaborated including 1) representing and decomposition methods of functions and motion behaviors; 2) action scheme representing method based on network plan techniques; and 3) variation and creation methods based on action scheme transformations.

关键词: mechanism system creative design     process model     function solving model     process action procedure     mechanisms knowledge base     principle of mechanism system composition    

Formation mechanism and modeling of surface waviness in incremental sheet forming

《机械工程前沿(英文)》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0679-1

摘要: Improving and controlling surface quality has always been a challenge for incremental sheet forming (ISF), whereas the generation mechanism of waviness surface is still unknown, which impedes the widely application of ISF in the industrial field. In this paper, the formation mechanism and the prediction of waviness are both investigated through experiments, numerical simulation, and theoretical analysis. Based on a verified finite element model, the waviness topography is predicted numerically for the first time, and its generation is attributed to the residual bending deformation through deformation history analysis. For more efficient engineering application, a theoretical model for waviness height is proposed based on the generation mechanism, using a modified strain function considering deformation modes. This work is favorable for the perfection of formation mechanism and control of surface quality in ISF.

关键词: surface waviness     incremental sheet forming     numerical simulation     formation mechanism     deformation history    

标题 作者 时间 类型 操作

A study on bearing characteristic and failure mechanism of thin-walled structure of a prefabricated subway

Lianjin TAO; Cheng SHI; Peng DING; Sicheng LI; Shang WU; Yan BAO

期刊论文

One DOF mechanism for the mechanical harvest of vines in an arbor structure and the validation of the

Osvaldo PENISI,José BOCCA,Horacio AGUILAR,Pedro BOCCA

期刊论文

Structural synthesis of ancient Chinese foot-operated silk-reeling mechanism

Kuohung HSIAO, Yuhsun CHEN, Hongsen YAN,

期刊论文

VITHM1 mediated green synthesis of silver nanoparticles: Mechanism and biological applications

Mani Abirami, Krishnan Kannabiran

期刊论文

Progressive collapse of 2D reinforced concrete structures under sudden column removal

El Houcine MOURID, Said MAMOURI, Adnan IBRAHIMBEGOVIC

期刊论文

KDD中双库协同机制的研究(Ⅰ)

杨炳儒,王建新

期刊论文

Preparation of nZVI embedded modified mesoporous carbon for catalytic persulfate to degradation of reactive black 5

期刊论文

Ribozyme and the mechanisms that underlie RNA catalysis

Timothy J. Wilson,Yijin Liu,David M. J. Lilley

期刊论文

朝鲜半岛构造系统地质环境演化及动力学机制的地球卫星遥感影像解译研究

胡东生,张华京,徐冰,田新洪,张国伟

期刊论文

Static behavior of planar intersecting CFST connection in diagrid structure

Ling LI, Xianzhong ZHAO, Ke KE

期刊论文

Study on the growth of platinum nanowires as cathode catalysts in proton exchange membrane fuel cells

Ruiqing Wang, Xiaolan Cao, Sheng Sui, Bing Li, Qingfeng Li

期刊论文

淀粉基API胶合木胶接结构破坏模式及失效机理

时君友,徐文彪,王淑敏

期刊论文

正交叠层机织布整体穿刺工艺的纤维弯曲伸长机理

朱建勋,何建敏,王海燕

期刊论文

Theory and method of mechanism system design

Huijun ZOU, Qinghua LIANG, Qing ZHANG

期刊论文

Formation mechanism and modeling of surface waviness in incremental sheet forming

期刊论文