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Numerical study on moving train parameter identification system through a simply supported bridge
Yi Wang,Weilian Qu 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.9
This paper presents a new experimental system for moving train parameter identification on bridge. The numerical method is adopted to simulate the experimental system and to investigate the effect of the system on identification of the moving train parameters. Displacement responses are obtained by solving the equation of motion of a simply supported bridge model. Basic parameters of the train (i.e., moving speed, wheel axle numbers, and axle spacing) are recognized with a self-designed parameter recognition system. Axle load values on bridge are identified with a load identification system based on simulated annealing genetic algorithm and by minimizing the errors between measured and reconstructed displacements from the moving train loads at each time step. Measured data are simulated by adding artificial noise to the calculated data. A series of numerical simulations is performed to analyze the effect of the system under various train situations. The results show that the experimental system is feasible and valid for identification of moving train parameters,thereby providing effective preparation for practice.
Yi Wang,Wei-Lian Qu 한국강구조학회 2011 International Journal of Steel Structures Vol.11 No.2
This paper presents a dynamic displacement influence line method for moving load identification on bridge. The finite element model of Poyang Lake continuous truss bridge-train systems is established and the dispersed modal shapes are acquired by modal analysis. Multi-axle moving train loads are identified with simulated annealing genetic algorithm by minimizing the errors between the measured displacements and the reconstructed displacements from the identified moving loads. In the identification process, the dynamic displacement influence line technique is used to calculate the time history displacement responses of the bridge to avoid solving equations of motion of the bridge repetitively. Several important parameters of the bridge-train system are discussed to investigate their effects on the proposed method. The results demonstrate that the proposed method is an accurate and efficient method for moving train load identification on complex bridges.
Mengnan Qu,Yichen Zhou,Lili Ma,Yi Zhang,Jiaxin Wang,Shanxin Xiong,Lihua Shen,Jinmei He 한국섬유공학회 2021 Fibers and polymers Vol.22 No.3
Stimulus-responsive materials with controllable oil/water separation performance have prodigious potentialapplication. Here, a new thought for low-cost, time-saving, flexible approach has been developed to prepare a pH-responsivematerial with switchable superamphiphobicity and superoleophobicity-superhydrophilicity. The as-prepared material can beeasily applied onto multifarious substrates and presents stable superamphiphobicity. However, when the modified material istreated by alkaline solution, its surface wettability turns superhydrophilicity and superoleophobicity, thus water is allowed topenetrate through the material whereas the oil was blocked on the surface. Moreover, the surface wettability can be recoveredto superamphiphobicity quickly via treating the material with acidic aqueous. Hence, such a controllable water wettabilityand stable oil repellency property endows the as-prepared material with excellent capability to separate water from oil/watermixture. In addition, the pH-responsive materials can maintain switchable wettability after being treated by acid and alkalinumerous cycles. Furthermore, the obtained materials also exhibit excellent recyclable, self-cleaning and flame-resistantperformance, which shows potential applications for smart water-oil separators and fire-shielding protectors.
LIANG QIAO,YI ZENG,CHAOQUN QU,XIAOYING HU,LIJUN SONG,YONGMING SUI 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.1
The adsorption and difusion of oxygen atom on the O-terminated ZnO ð 000?1 Þ surface havebeen systematically investigated based on ¯rst-principles density functional theory. The resultsshow that the surface relaxation of the ZnO ð 000?1 Þ surface is signi¯cant. In the view of themaximization of the adsorption energy, the preferred site for the adsorption of oxygen atom is thetop-O site above the oxygen atom of the ¯rst Zn – O bilayer. There is chemical bond formedbetween the adsorbed oxygen atom and the oxygen atom on the surface, which will result in theredistribution of the charges. The charges transfer from the ZnO surface to the adsorbed oxygenatom, which will heighten the surface potential of ZnO surface and increase the surface workfunction. Moreover, the di®usion of the oxygen atom on the ZnO surface has also been investi-gated, and the potential barriers of the difusion have been identi¯ed to reveal the adsorptionstability
Spurious mode distinguish by eigensystem realization algorithm with improved stabilization diagram
Chun-Xu Qu,Ting-Hua Yi,Xiao-Mei Yang,Hong-Nan Li 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.6
Modal parameter identification plays a key role in the structural health monitoring (SHM) for civil engineering. Eigensystem realization algorithm (ERA) is one of the most popular identification methods. However, the complex environment around civil structures can introduce the noises into the measurement from SHM system. The spurious modes would be generated due to the noises during ERA process, which are usually ignored and be recognized as physical modes. This paper proposes an improved stabilization diagram method in ERA to distinguish the spurious modes. First, it is proved that the ERA can be performed by any two Hankel matrices with one time step shift. The effect of noises on the eigenvalues of structure is illustrated when the choice of two Hankel matrices with one time step shift is different. Then, a moving data diagram is proposed to combine the traditional stabilization diagram to form the improved stabilization diagram method. The moving data diagram shows the mode variation along the different choice of Hankel matrices, which indicates whether the mode is spurious or not. The traditional stabilization diagram helps to determine the concerned truncated order before moving data diagram is implemented. Finally, the proposed method is proved through a numerical example. The results show that the proposed method can distinguish the spurious modes.