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Guided wave propagation in multilayered piezoelectric structures

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Science china(Physics,Mechanics & Astronomy) 2009年第7期52卷 1094-1104页

作者： GUO YongQiang1, CHEN WeiQiu2,3 & ZHANG YongLiang4 1 Key Laboratory of Mechanics on Disaster and Environment in Western china, Ministry of Education, and school of civil engineering and Mechanics, Lanzhou University, Lanzhou 730000, china 2 Key Laboratory of Soft Soils and Geoenvironmental engineering, Ministry of Education, and Department of civil engineering, Zhejiang University, Hangzhou 310058, china 3 Department of engineering Mechanics, Zhejiang University, Hangzhou 310027, china 4 school of civil engineering, Lanzhou Jiaotong University, Lanzhou 730070, china Key Laboratory of Mechanics on Disaster and Environment in Western china Ministry of Education and School of Civil Engineering and Mechanics Lanzhou University Lanzhou 730000 China Key Laboratory of Soft Soils and Geoenvironmental engineering Ministry of Education and Department of Civil Engineering Zhejiang University Hangzhou 310058 China Department of engineering Mechanics Zhejiang University Hangzhou 310027 China school of civil engineering Lanzhou Jiaotong University Lanzhou 730070 China

A general formulation of the method of the reverberation-ray matrix (MRRM) based on the state space formalism and plane wave expansion technique is presented for the analysis of guided waves in multilayered piezoelectric structures. Each layer of the structure is made of an arbitrarily anisotropic piezoelectric material. Since the state equation of each layer is derived from the three-dimensional theory of linear piezoelectricity, all wave modes are included in the formulation. Within the framework of the MRRM, the phase relation is properly established by excluding exponentially growing functions, while the scattering relation is also appropriately set up by avoiding matrix inversion operation. Consequently, the present MRRM is unconditionally numerically stable and free from computational limitations to the total number of layers, the thickness of individual layers, and the frequency range. Numerical examples are given to illustrate the good performance of the proposed formulation for the analysis of the dispersion characteristic of waves in layered piezoelectric structures.

关键词： multilayered piezoelectric structures the method of reverberation-ray matrix guided waves dispersion characteristic

Performance-based methodology for assessing seismic vulnerability and capacity of buildings

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Earthquake engineering and engineering Vibration 2010年第2期9卷 157-165页

作者： Lin Shibin1, Xie Lili1, 2,Gong Maosheng1,2 and Li Ming1,3 1.Institute of engineering Mechanics,china Earthquake Administration, Harbin 150080, china 2.school of civil engineering,Harbin Institute of Technology,Harbin 150090, china 3.school of civil engineering,Shenyang Jianzhu University,Shenyang 11016, china Institute of engineering Mechanics China Earthquake Administration Harbin 150080 China

This paper presents a performance-based methodology for the assessment of seismic vulnerability and capacity of buildings. The vulnerability assessment methodology is based on the HAZUS methodology and the improved capacity- demand-diagram method. The spectral displacement (Sd) of performance points on a capacity curve is used to estimate the damage level of a building. The relationship between Sd and peak ground acceleration (PGA) is established, and then a new vulnerability function is expressed in terms of PGA. Furthermore, the expected value of the seismic capacity index (SCev) is provided to estimate the seismic capacity of buildings based on the probability distribution of damage levels and the corresponding seismic capacity index. The results indicate that the proposed vulnerability methodology is able to assess seismic damage of a large number of building stock directly and quickly following an earthquake. The SCev provides an effective index to measure the seismic capacity of buildings and illustrate the relationship between the seismic capacity of buildings and seismic action. The estimated result is compared with damage surveys of the cities of Dujiangyan and Jiangyou in the M8.0 Wenchuan earthquake, revealing that the methodology is acceptable for seismic risk assessment and decision making. The primary reasons for discrepancies between the estimated results and the damage surveys are discussed.

关键词： performance-based vulnerability building damage seismic capacity software HAZUS

Internet-based collaborative pseudo-dynamic testing of multi-span bridge structure

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Progress in Natural Science:Materials International 2009年第5期19卷 623-633页

作者： Dapeng Wang a, Shizhu Tiana, Xinjiang Caia, Yunlei Fan b, Yan Xiaob,c a school of civil engineering, Harbin Institute of Technology, Harbin 150090, china b school of civil engineering, Hunan University, Changsha 410082, china c Department of civil engineering, University of Southern California, Los Angeles, CA 90089, USA [a]school of civil engineering Harbin Institute of Technology Harbin 150090 China [b]School of Civil Engineering Hunan University Changsha 410082 China [c]Department of Civil Engineering University of Southern California Los Angeles CA 90089 USA

In this paper, the first Internet-based collaborative pseudo-dynamic testing of a multi-span bridge system in china’s mainland is presented in detail, which has been carried out by the collaboration of Hunan University (HNU), Harbin Institute of Technology (HIT) and Tsinghua University (TU) in china’s mainland, and the University of Southern California (USC) in the USA. The prototype system of Russion River Bridge at Southern California in America is illustrated. Different testing specimens, testing equipments and substructure boundary conditions at HNU and HIT laboratories are described. A network protocol platform for collaborative pseudo-dynamic testing, called NetSLab, and some function modules developed on the use of its standardized interface are introduced. Aiming at the MTS system widely used in structural testing, two approaches are presented to implement the communication interface between NetSLab and testing equipment, respectively, studied by HNU and HIT. The integrated networked testing system and collaborative testing procedures are presented. The testing results manifest that the networked collaborative testing system with powerful capability provides a testing platform with good coordination for complex models or actual structures, and achieves remote sharing of testing equipments.

关键词： Internet-based collaborative pseudo-dynamic testing Multi-span bridge structure Network protocol platform Communication interface Remote sharing of testing equipment

WAVE BOTTOM LAYERS DYNAMIC WITH SUSPENDED SEDIMENT OVER VORTEX RIPPLES

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Journal of Hydrodynamics 2004年第2期16卷 201-208页

作者： JIANGChang-bo BAIYu-chuan ZHAOZi-dan ZHANGHong-wu CollegeofRiverandOceanengineeringChangshaUniversityofScienceandTechnology Changsha410076China InstituteofSedimentonRiverandCoastengineering TianjinUniversityTianjin300072China schoolofcivilengineering TsinghuaUniversityBeijing100084China

Vortex ripple is widely formed in the coastal region, and the dynamic ofvortex is quite important because it is responsible for sediment transport. The flow structurearound the vortex ripples can be modeled as 2D flow due to the geometry of the flow boundaries. Inthis paper, 2D Large-Eddy-Simulation (LES) method was used to predict the flow structure and thedynamic of vortex in the bottom layers under the action of the wave, the numerical simulationresults show a completely process of vortex formation, evolvement and disappearance. Based on thestudy of flow structure, the suspended sediment transport was modeled in present paper. Thesimulated sediment concentrations were compared to measurements from the literature. The agreementbetween the time averaged simulated concentration profiles and measurements is satisfactory. For ahigh setting velocity, the suspended sediment is confined to the vicinity of the bed, and it isdominated by the local bottom shear stress. For a small setting velocity, the suspension is moredominated by the characteristic of vortex. There are two suspended sediment transport peaks observedin the cross-section at the trough and crest in the half period, the second peak is due to theseparation bubble taking the sediment.

关键词： wave boundary layer vortex ripple suspended sediment numerical model

Experimental study on bed-load sediment transport under irregular wave and current combined flow

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Acta Oceanologica Sinica 2001年第2期20卷 271-280页

作者： Wu Yongsheng,Qin Chongren (1. Department of Hydraulic engineering, Tsinghua University, Beijing 100084, china 2. school of civil engineering, Tianjin University, Tianjin 300072, china) Department of Hydraulic engineering Tsinghua University Beijing 100084 China

Using an irregularly oscillating tray and flume, a series of experiments are completed to evaluate bed-load sediment transport rate under irregular wave -current coexistent field. Testing conditions include three interaction angles 0', 45', 90' and two kinds of median sizes (0.38 and 1.10 mm). The results of transport rate show that the net sediment transport rate can be expressed approximately as the function of the maximum bottom shear stress of waves, mean shear stress of current and the grain size.

关键词： Irregular wave-current bed-load transport rate

Classified real-time flood forecasting by coupling fuzzy clustering and neural network

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International Journal of Sediment Research 2010年第2期25卷 134-148页

作者： Minglei REN1, Bende WANG2, Qiuhua LIANG3, and Guangtao FU41 Dr., school of civil & Hydraulic engineering, Dalian University of Technology, Dalian 116024, china 2 Prof., school of civil & Hydraulic engineering, Dalian University of Technology, Dalian 116024, china 3 Lecture, school of civil engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK 4 Lecture, school of engineering, Computing and Mathematics, University of Exeter, Exeter EX4 4QF, UK [a] Dr. School of Civil & Hydraulic Engineering Dalian University of Technology Dalian 116024 China [b] Prof. School of Civil & Hydraulic Engineering Dalian University of Technology Dalian 116024 China [c] Lecture School of Civil Engineering Geosciences Newcastle University Newcastle upon Tyne NE1 7RU UK [d] Lecture School of Engineering Computing Mathematics University of Exeter Exeter EX4 4QF UK

This paper presented a new classified real-time flood forecasting framework by integrating a fuzzy clustering model and neural network with a conceptual hydrological model. A fuzzy clustering model was used to classify historical floods in terms of flood peak and runoff depth, and the conceptual hydrological model was calibrated for each class of floods. A back-propagation (BP) neural network was trained by using real-time rainfall data and outputs from the fuzzy clustering model. BP neural network provided a rapid on-line classification for real-time flood events. Based on the on-line classification, an appropriate parameter set of hydrological model was automatically chosen to produce real-time flood forecasting. Different parameter sets was continuously used in the flood forecasting process because of the changes of real-time rainfall data and on-line classification results. The proposed methodology was applied to a large catchment in Liaoning province, china. Results show that the classified framework provided a more accurate prediction than the traditional non-classified method. Furthermore, the effects of different index weights in fuzzy clustering were also discussed.

关键词： Real-time flood forecasting Flood classification Conceptual hydrological model Fuzzy clustering Neural networks

Influence of polymer on shrinkage and anti-cracking performance of mortar

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Rare Metals 2007年第S1期26卷 120-123页

作者： LI Jiahe1),OU Jinping2),and WANG Zheng1)1) school of Material Science and engineering,Harbin Institute of Technology,Harbin 150001,china 2) school of civil engineering,Harbin Institute of Technology,Harbin 150001,china Harbin Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China Harbin Inst Technol Sch Civil Engn Harbin 150001 Peoples R China

A self-designed restrained ring test was applied to investigate cracking of *** cracking total weigh W and cracking control rate K were applied to evaluate anti-cracking performance of *** the above method,the influence of polymer on the shrinkage and anti-cracking performance was *** microstructures of mortar specimens were investigated by means of *** results indicated that the addition of polymer can efficiently reduce the shrinkage of mortar and improve the anti-cracking performance of mortar.

关键词： mortar shrinkage cracking anti-cracking

A study of ice response spectra

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Acta Oceanologica Sinica 2009年第3期28卷 114-119页

作者： LIU Chunguang JIA Lingling State key Laboratory of Coastal and Offshore engineering Dalian University of TechnologyDalian 116024 China school of civil Hydraulic engineering Dalian University of Technology Dalian 116024 China

Some problems concerning the ice forces and ice response spectra are studied from both theoretical and practical points of view. On the basis of structural analysis,the analysis method of ice response spectra is proposed, since it plays an important role in the prediction of maximum structural response in cold regions. And it is illustrated that it is easy to study the structural response to ice using the ice response spectra.

关键词： ice force ice response spectra structural analysis ice-induced vibration

Preparation and characterization of uniform circinate aggregates of sheet ZnO nanoparticles

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Rare Metals 2008年第1期27卷 36-40页

作者： LIU Jiaxiang DING Deling WANG Lisheng and HAN Yuexin The State Key Laboratory of Chemical Resource engineering College of Materials Science and Engineering Beijing University of Chemical Technology Be~iing100029 China school of Resources and civil engineering Northeastern University Shenyang 110004 China

Uniform circinate aggregates of sheet ZnO nanoparticles with a specific surface area of 24 m^2·g^-1 were prepared by the direct precipitation *** circinate aggregates were hexagonal ZnO,with the wall thickness ranging from 0.5 to 1 μm and the diameter ranging from 5 to 10 μ*** backs of the circinate aggregates were regularly arranged by numerous sheet ZnO nanoparticles with a thickness of 30-80 nm and a diameter of 300-400 *** precursors were aggregates of sheet Zn5（CO3）2（OH）6 nanoparticles,which were decomposed into ZnO by calcining in air in the range of 200-285°C,and the ZnO retained the similar special *** C2H5OH content had a significant effect on the formation of sheet *** centripetal force,the Van der Waals force,and the hydrogen bond were deduced as the driving forces of the formation of circinate.

关键词： nano-ZnO circinate aggregates preparation technology microstructure characterization