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Vertical Upheaval Buckling of Submarine Buried Heated Pipelines with Initial Imperfection

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Transactions of Tianjin University 2011年第2期17卷 138-145页

作者：王武刚刘润闫澍旺徐余 School of civil engineering Tianjin University Tianjin Architecture design Institute

In this paper,a theoretical solution of vertical buckling is proposed with regard to the typical initial imperfection cases of submarine *** tools are applied to predicting the occurrence and consequence of inservice buckling of a buried heated pipeline in Bohai *** evaluation is performed to ensure the pipeline structural integrity during operation under loading *** protection measures are proposed and their validities are *** show that for the same magnitude of initial imperfection,the upheaval buckling of pipeline with isolated prop model is the most likely to *** empathetic model represents a special sub-case of continuous prop model,and the calculated buckle temperature is between the first stage and the second stage of post-upheaval buckling of continuous prop *** the larger the initial imperfection,the less the axial force required for the upheaval ***,it can be seen that a peak point appears on the curves of temperature difference against buckling amplitude for small initial ***,trenching-burial is one kind of protection measures preventing the pipeline from thermal *** covered depth-to-diameter ratio depends on the design conditions and subsoil *** the given pipeline in this paper,the covered depth-to-diameter ratio is recommended to be 5.

关键词： submarine buried pipeline thermal stress initial imperfection upheaval buckling protection measure

Prediction of vibrations from underground trains on Beijing metro line 15

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Journal of Central South University 2010年第5期17卷 1109-1118页

作者：丁德云刘维宁 GUPTA S LOMBAERT G DEGRANDE G School of civil engineering Beijing Jiaotong University Department of civil engineering K.U.Leuven Beijing Urban engineering design and Research Institute Co. Ltd

The impact of vibrations due to underground trains on Beijing metro line 15 on sensitive equipment in the Institute of Microelectronics of Tsinghua University was discussed to propose a viable solution to mitigate the *** the state-of-the-art three-dimensional coupled periodic finite element-boundary element(FE-BE) method,the dynamic track-tunnel-soil interaction model for metro line 15 was used to predict vibrations in the free field at a train speed of 80 km/*** types of tracks(direct fixation fasteners,floating slab track and floating ladder track) on the Beijing metro network were considered in the model. For each track,the acceleration response in the free field was *** numerical results show that the influence of vibrations from underground trains on sensitive equipment depends on the track *** frequencies above 10 Hz,the floating slab track with a natural frequency of 7 Hz can be effective to attenuate the vibrations.

关键词： vibration prediction underground trains coupled periodic FE-BE method track types

Ground motion spatial variability effects on seismic response control of cable-stayed bridges

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Earthquake engineering and engineering Vibration 2011年第1期10卷 37-49页

作者： Shehata E. Abdel Raheem Toshiro Hayashikawa Uwe Dorka civil engineering Department Faculty of Engineering Assiut University Bridge and Structural design engineering Hokkaido University Steel & Composite Structures Kassel Universitt

The spatial variability of input ground motion at supporting foundations plays a key role in the structural response of cable-stayed bridges （CSBs）; therefore, spatial variation effects should be included in the analysis and design of effective vibration control systems. The control of CSBs represents a challenging and unique problem, with many complexities in modeling, control design and implementation, since the control system should be designed not only to mitigate the dynamic component of the structural response but also to counteract the effects of the pseudo-static component of the response. The spatial variability effects on the feasibility and efficiency of seismic control systems for the vibration control of CSBs are investigated in this paper. The assumption of uniform earthquake motion along the entire bridge may result in quantitative and qualitative differences in seismic response as compared with those produced by uniform motion at all supports. A systematic comparison of passive and active system performance in reducing the structural responses is performed, focusing on the effect of the spatially varying earthquake ground motion on the seismic response of a benchmark CSB model with different control strategies, and demonstrates the importance of accounting for the spatial variability of excitations.

关键词： cable-stayed bridge vibration control earthquake spatial variation seismic design semi-active control

Determination of Wind Pressure Coefficients for Arc-Shaped Canopy Roof with Numerical Wind Tunnel Method

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Transactions of Tianjin University 2009年第5期15卷 360-365页

作者：尹越张天舒韩庆华杨惠东 School of civil engineering Tianjin University Tianjin Key Laboratory of civil engineering Structures and New Materials Tianjin Architecture design Institute The Second Survey and design Institute of China Railways

In this paper,the wind load on an arc-shaped canopy roof was studied with numerical wind tunnel method(NWTM) .Three-dimensional models were set up for the canopy roof with opened or closed *** air flow around the roof under wind action from three directions was analysed *** pressure coefficients on the canopy roof were determined by *** results of NWTM agreed well with those of wind tunnel test for the roof with opened skylights,which verified the applicability and rationality of *** effect of the closure of skylights was then investigated with *** was concluded that the closure of the skylights may increase the wind suction on the top surface of the roof greatly and should be considered in the structure design of the canopy roof.

关键词： arc-shaped canopy roof numerical wind tunnel method wind pressure coefficient wind tunnel test skylights

COMPLEXITY OF SYSTEM MAINTAINABILITY ANALYSIS BASED ON THE INTERPRETIVE STRUCTURAL MODELING METHODOLOGY： TRANSDISCIPLINARY APPROACH

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Journal of Systems Science and Systems engineering 2016年第2期25卷 254-268页

作者： A. Ertas M.W. Smith D. Tate W.D. Lawson T.B. Baturalp Department of Mechanical engineering Texas Tech University Lubbock TX USA 79410 Department of industrial design Xi 'an Jiaotong-Liverpool University Suzhou 215123 Jiangsu China Department of civil engineering Texas Tech University Lubbock TX USA 79410

This paper outlines a diagnostic approach to quantify the maintainability of a Commercial off-the-Shelf （COTS）-based system by analyzing the complexity of the deployment of the system components. Interpretive Structural Modeling （ISM） is used to demonstrate how ISM supports in identifying and understanding interdependencies among COTS components and how they affect the complexity of the maintenance of the COTS Based System （CBS）. Through ISM analysis we have determined which components in the CBS contribute most significantly to the complexity of the system. With the ISM, architects, system integrators, and system maintainers can isolate the COTS products that cause the most complexity, and therefore cause the most effort to maintain, and take precautions to only change those products when necessary or during major maintenance efforts. The analysis also clearly shows the components that can be easily replaced or upgraded with very little impact on the rest of the system.

关键词： COTS Based System maintainability complexity Interpretive Structural Modeling

Shaking table test and numerical analysis of offshore wind turbine tower systems controlled by TLCD

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Earthquake engineering and engineering Vibration 2015年第1期14卷 55-75页

作者： Chen Jianbing Liu Youkun Bai Xueyuan State Key Laboratory of Disaster Reduction in civil engineering & School of civil engineering Tongji University Shanghai Electric Power design Institute Co. Ltd Jiang Architects & Engineers

A wind turbine system equipped with a tuned liquid column damper （TLCD） is comprehensively studied via shaking table tests using a 1/13-scaled model. The effects of wind and wave actions are considered by inputting response- equivalent accelerations on the shaking table. The test results show that the control effect of the TLCD system is significant in reducing the responses under both wind-wave equivalent loads and ground motions, but obviously varies for different inputs, Further, a blade-hub-tower integrated numerical model for the wind turbine system is established. The model is capable of considering the rotational effect of blades by combining Kane＇s equation with the finite element method. The responses of the wind tower equipped with TLCD devices are numerically obtained and compared to the test results, showing that under both controlled and uncontrolled conditions with and without blades＇ rotation, the corresponding responses exhibit good agreement. This demonstrates that the proposed numerical model performs well in capturing the wind-wave coupled response of the offshore wind turbine systems under control. Both numerical and experimental results show that the TLCD system can significantly reduce the structural response and thus improve the safety and serviceability of the offshore wind turbine tower systems. Additional issues that require further study are discussed.

关键词： offshore wind turbine shaking table test TLCD numerical model vibration control

Prediction of Vibration Characteristics in Beam Structure Using Sub-Scale Modeling with Experimental Validation

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Chinese Journal of Mechanical engineering 2015年第5期28卷 928-934页

作者： ZAI Behzad Ahmed SAMI Saad KHAN M Amir AHMAD Furqan PARK Myung Kyun Structure design and Development Directorate Institute of Space Technology Department of civil and Environmental engineering KAIST Department of Mechanical engineering Myongji University

Geometric or sub-scale modeling techniques are used for the evaluation of large and complex dynamic structures to ensure accurate reproduction of load path and thus leading to true dynamic characteristics of such structures. The sub-scale modeling technique is very effective in the prediction of vibration characteristics of original large structure when the experimental testing is not feasible due to the absence of a large testing facility. Previous researches were more focused on free and harmonic vibration case with little or no consideration for readily encountered random vibration. A sub-scale modeling technique is proposed for estimating the vibration characteristics of any large scale structure such as Launch vehicles, Mega structures, etc., under various vibration load cases by utilizing precise scaled-down model of that dynamic structure. In order to establish an analytical correlation between the original structure and its scaled models, different scale models of isotropic cantilever beam are selected and analyzed under various vibration conditions（ i.e. free, harmonic and random） using finite element package ANSYS. The developed correlations are also validated through experimental testing The prediction made from the vibratory response of the scaled-down beam through the established sets of correlation are found similar to the response measured from the testing of original beam structure. The established correlations are equally applicable in the prediction of dynamic characteristics of any complex structure through its scaled-down models. This paper presents modified sub-scale modeling technique that enables accurate prediction of vibration characteristics of large and complex structure under not only sinusoidal but also for random vibrations.

关键词： sub-scale modeling resonance frequency vibration characteristics scale factors power spectral density

Mineralogical characterization and comprehensive utilization of micro-fine tantalum–niobium ores from Songzi

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Rare Metals 2015年第4期34卷 282-290页

作者： Zhi-Tao Yuan Ji-Wei Lu Hui-Fang Wu Jiong-Tian Liu School of Resources & civil engineering Northeastern University Department of design Northeastern University Engineering and Research Institute Co. Ltd.

The mineralogical characteristics of tantalumniobium ores from Songzi were investigated using mineral liberation analyzer （MLA） and chemical analysis. In particular, the chemical composition, phase composition, particle size, and dissemination characteristics of the ores were studied in detail. Results show that Ta2O5 and Nb2O5 have grades of 0.013 % and 0.011%, respectively. The main valuable minerals in the ores are tantalite, col- umbite, tantalum-niobite, and microlite, and the gangue minerals associated with tantalum-niobium minerals mainly include quartz, kaolinite, illite, feldspar, and mica among others. The minerals are embedded in a complex manner. Tantalum-niobium minerals with most particle sizes of -0.040 mm are disseminated in minerals, such as mica, illite, quartz, and partially intergrown with topaz and zircon, where they could not be easily liberated. Thus, the ores are classified as low-grade, micro-fine, and refractory tantalum-niobium ores. Based on this consideration, the process of classification-gravity concentration-magnetic separation-middlings regrinding and gravity concentration are finally determined and satisfactory indices are obtained. Two rough concentrates are produced： Concentrate I has Ta2O5 and Nb2O5 grades of 7.0292 % and 3.546 %, respectively, as well as recovery of 49.42 % and 35.46 %. By comparison, Concentrate Ⅱ has Ta2O5 and Nb2O5 grades of 7.0292 % and 3.546 %, respectively, as well as recovery of 49.42 % and 35.46 %.

关键词： Mineralogy Tantalum-niobite Comprehensive utilization Micro-fine particles

Distributed TLDs in RC floors and their vibration reduction efficiency

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Earthquake engineering and engineering Vibration 2008年第1期7卷 107-112页

作者：叶列平陆新征曲哲侯建群 Key Laboratory of Structural engineering and Vibration of China Education Ministry Department of Civil Engineering Tsinghua University Tsinghua Institute of Architectural design

A novel distributed tuned liquid damper （DTLD） for reducing vibration in structures is proposed in this paper. The basic working principle of the DTLDs is to fill the empty space inside the pipes or boxes of cast-in-situ hollow reinforced concrete （RC） floor slabs with water or other liquid. The pipes or boxes then work as a series of small TLDs inside the structure, to increase the damping ratio of the entire structural system. Numerical simulation that accounts for the fluid- structure conpling effect is carried out to evaluate the vibration-reduction efficiency of the DTLDs. The results show that the DTLDs are able to considerably increase the damping of the structure and thus reduce its vibration. An additional benefit is that the DTLDs do not require architectural space to be added to the structure.

关键词： distributed tuned liquid damper (DTLD) fluid-structure interaction (FSI) vibration reduction hollow floor slab