Vibration, Structural Engineering and Measurement II

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Authors: Jian Hui Wang, Li Zhang, Wen Jie Chen, Hua Di Chen
Abstract: There were a lot of small work pieces in the industry, like the lamella and the small steel wire line etc. Some of them could not be touched directly, for high request in some production line to the works piece thickness accuracies which depend on an on-line examination for manpower could not satisfy a production line anymore. This paper introduced a kind of measure system based on the production line of linear CCD, with the control chip of EPM3064A and measure chip of TCD132. Sampling the output signal from CCD module and sending the datum to host computer, built by VB with AVR128 MCU in RS-232 serial communication mode and displayed the waveform images with binarization in real time and analyzed them. Finally, with the help of Key9 software to carry on unmanned auto supervision and realized message sending function. The experiment showed the precision, rapid of this system and good humanization of control effect as a result.
2046
Authors: Shao Feng Dong, Bao Qiang Du, Wei Zhou
Abstract: According to Doppler effect of satellite on the time synchronization technology between satellite and the ground station, a real-time measurement method of Doppler is proposed based on GPS carrier signals. Using Doppler observations from GPS receiver, the method can real-timely measure Doppler frequency shift of GPS including dynamic Doppler and media Doppler whose error can be timely modified in the receiver end. Simulation results show that the frequency shift caused by dynamic Doppler, a main influencing factor in the course of transmission of time-frequency signal by GPS satellite, is between plus or minus several thousands Hz. Comparing to traditional measurement method of Doppler, the method makes it possible to fast track phase of signal in large dynamic range in synchronous technology.
2050
Authors: Xiao Feng Li, Xing Chao Fan, Li Min Jia
Abstract: Compressed sensing technology is a new approach in the field of signal processing. It can achieve data acquisition and compression at the same time, and express the original signal in a simple way. Network monitoring technology used in detecting the fault of the train’s rolling bearing always produce large amounts of datum. Too much of the parse inspection data cause a lot of unnecessary cost of energy and network bandwidth. In this article we propose a compressed sensing method to deal with the inspection date of train’s rolling bearing which will be transferred in the sensor network to reduce the data quantity. Experimental result show that, after compression and reconstruction, the reconstructed signal still contains most of the information and energy of the original signal, we can still detect the fault of train’s rolling bearing from the reconstructed signal accurately.
2056
Authors: Luan Xiong Chen, Wei Xu, Xu Guang Huang
Abstract: In order to monitoring the health of the structure, a quasi-distributed fiber Bragg grating (FBG) interrogator based on two-channel theory of the arrayed waveguide grating (AWG) demultiplexer is presented. As is known, a slightly change of the temperature or strain or other related parameters applied on the FBG will lead to a shift of the Bragg wavelength of the FBG, which makes sense on the precisely temperature and strain monitoring of structures, including viaduct bridges, towers, railway, skyscraper, etc. It can be interrogated by the relative intensity of two-adjacent-channel of the AWG-based demultiplexer, which offers a low-cost, high sensitivity for the interrogation of FBG distributed sensors.
2062
Authors: Kao Shan Dai, Xiao Song Ren, Qing Jun Chen, Bin Zhao
Abstract: The laser Doppler vibrometer is a non-contact sensing technique developed based on the Doppler effect of a laser beam emerging from a subject surface. As a vibration transducer, the laser Doppler vibrometer offers many advantages over the conventional contact vibration sensors. It allows remote, non-intrusive measurement of structural vibration and it is very useful in scenarios when traditional contacting measurement is inconvenient. In this paper, four laser-based structural dynamic studies were presented and some results were briefly reported, which include laboratory dynamic testing of a bolted steel beam, a scaled-down high-rise building model, and a prestressed concrete reaction wall, and field vibration measurement of a viaduct bridge. Through these demonstrating cases, it is anticipated to help civil engineers get familiar with the laser-based sensing technology and to extend their selections for effective measurement approaches during experimental research.
2066
Authors: Dong Qin, Xue Qin Zheng, Fa Meng Wang, He Zhi Liu
Abstract: On the basis of the analysis of the displacement of concrete dam and its related influential factors, based on the evolvement of nonlinear dynamics of concrete dam, it can effectively identify the mutations position of measured value and the attribute interval of dynamical system applied with the wavelet analysis, dynamic structural mutation theory and other numerical analysis methods. When detecting after separating structural mutation sequence, it can finally get the relative stable displacement time series of dynamical structure, so it can realize the diagnostic separation of the monitoring information effective interval. At the end of the paper, through applying a certain concrete arch dam, it is proved that the proposed method of concrete dam mutations diagnosis of is of great significance for the real-time monitoring of the workability state of a dam.
2072
Authors: Jian Bo Sun, Dong Wang
Abstract: Deformation of foundation pit is a complex, can not be quantified, factors affecting multiple process. Using curve fitting model and time series AR ( n ) model for the combined model on deformation of foundation pit displacement prediction. By the depth of the pit excavation and supporting different direction condition, segmentation modeling prediction. With the development of foundation pit deformation, constantly adding new data, and delete the old data, to modeling, implementation of the whole process control of deformation and displacement prediction. Combined model to the prediction of first data, the relative error can be controlled within five percent. Therefore,the model can be used to control the deformation of foundation pit projects that require high, can also be used for other models predict data close to the alarm value of a contrast.
2078
Authors: Chi Guan, Zhang Hua Lou, Hai Jian Xie
Abstract: Mercury intrusion porosimetry injection is important in assessing microscopic pore structure of reservoirs. This paper introduces an estimated function for investigating the pore characteristic of western Sichuan tight gas reservoir based on VG model. Better correlations between the measured and estimated results have been obtained using VG model. Representative parameters were obtained by fitting the predictions of VG model to the experimental data, and then the estimated formulation was proposed for the studied reservoir. Correlation analysis of the parameters of VG model confirms that absolute permeability and irreducible water saturation are important in mercury injection porosimetry. The approach applied in this paper is helpful in investigating tight reservoirs, especially in the common cases when measurement is difficult to carry out, partly because of complicated variability in the field, and partly because measuring is time-consuming and expensive.
2082
Authors: Jian Chen, Zhong Qi Yue, Si Jing Liu
Abstract: In Hong Kong, there are so many drill works for landslide prevention, such as drilling holes for soil nailing. To recognize the geotechnical condition of slope in detail based on these drillholes, we have developed and invented the drilling process monitoring (DPM) technique to accurately and quickly quantify and characterize the mechanical strength distribution beneath the slope surface. This technique is associated with the conventional air-driven rotary-percussive drilling machines with down-the-hole hammer. This drilling machine is manually portable to quickly form holes of upto 100 m deep in sloping ground. Such ground can comprise any kinds of geomaterials from soft or loose geomaterials such as caverns, clay or sand to extremely hard or strong geomaterials such concrete or granite. Therefore, we have proposed an innovative approach by using DPM method to accurately and quickly quantify the ground conditions in slopes in mountainous regions. It is trusted that the proposed approach will be able to upgrade our current slope engineering practice in mountainous regions.
2088
Authors: Qiao Lin Xiao, Fen Lü
Abstract: Aiming at the Hainan volcanic lava the geological characteristics, the application of geological radar detection technology in the geological environment of signal respond, combined with the added drilling data is compared, established the goal of geological radar image characteristics of geology, summarized the poor geological conditions in the area of geological radar signal response law. Field test shows that the radar reflected wave group of wave characteristic in volcanic lava can distinguish different geological layer reflection wave group, and via studying their relationship and change trend, to achieve the purpose of geological interpretation, and determine the adverse lava geology development stages , for design and construction to provide the reliable foundation material, effective use of survey for the design and construction of the guidance function.
2093

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