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Ding Y.,Harbin Institute of Technology | Zhao B.Y.,Harbin Institute of Technology | Wu B.,Harbin Institute of Technology | Xu G.S.,Harbin Institute of Technology | And 3 more authors.
Mechanical Systems and Signal Processing | Year: 2015

The structural damage incurred in a seismic event is always time-variant. In this paper, a new time-variant structural system identification method is proposed based on a two-stage strategy and incomplete structural acceleration responses. In the first stage, an external excitation identification method is developed for a time-variant structural system. The unknown structural response could be re-constructed with the average acceleration discrete algorithm in this stage. In the second stage, structural parameter is identified and updated with a reduced extended Kalman filter which can improve the computational effort. The re-constructed structural response and identified external excitation are used in the second stage for the damage identification and model updating. The proposed method is validated numerically with the simulation of a fifteen-storey shear frame structure subject to earthquake excitation. A model of a fourteen-storey concrete shear wall building was also studied experimentally with shaking table tests to further validate the proposed method. This shear wall building has a two-storey steel frame on top with base isolation. Both the stiffness of the model and the interface force in the isolator at the bottom of the steel frame during the seismic excitation were estimated with the proposed method. Results from both numerical simulations and laboratory tests indicate that the proposed method can be used to identify structural parameters and external excitations effectively based on a few number of polluted structural acceleration measurements. © 2015 Elsevier Ltd. Source


Cai C.,China Institute of Metrology | Xu J.,Beijing Institute of Architecture Design | Li J.,China Institute of Metrology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

The intrinsic microseism in a precision metrology laboratory of National Institute of Metrology is used to evaluate the resolution of vibration transducers. The precision metrology laboratory is located in the Changping experimental base of National Institute of Metrology. The intrinsic microseism has been measured since 2003. The frequency of the intrinsic microseism is about 3.2 Hz, and the velocity magnitude of the intrinsic microseism is about 5×10-8 m/s. The long term measure proved the frequency and magnitude of the intrinsic microseism is stable, and it can be used as a natural standard to evaluate the resolution of vibration transducers. The vibration transducers and a reference vibration transducer are located in a seismic block. The reference vibration transducer has enough vibration resolution to measure the intrinsic microseism. The vibration transducers and the reference vibration transducer measure and record the ambient vibration at the same time in a measurement period, e.g. 15 minutes, 2 hours or 24 hours. The recorded data are analyzed by FFT with average analysis in full-time process to gain the average spectrum. If the 3.2 Hz intrinsic microseism could be measured by the vibration transducers, the resolution of the vibration transducers will precede the magnitude of the 3.2 Hz intrinsic microseism which is measured by the reference vibration transducer. The signal noise ratio in the average spectrum can further affect the measure results. © 2013 SPIE. Source


Zhang J.,University of Science and Technology Beijing | Mu Z.,University of Science and Technology Beijing | Gan M.,Beijing Institute of Architecture Design
Advanced Materials Research | Year: 2011

wave-passage effect of the seismic is the main reason of multi-support excitations, and there are always two analysis methods which are large mass method and acceleration method to study on the multi-support excitations, this paper take one kind of trussed structure as an example, use the two methods to consider the wave-passage effect of seismic, compare the difference between the results from using the two methods, and also compare the difference between single-support and multi-support excitations. This paper draw a conclusion that it is a precise way to using ABAQUS to analysis the wave-passage effect of the seismic; wave-passage effect of the seismic has an great influence on the reaction of long-span spatial structures, it must be considered in the similar projects; and the large method and acceleration method both have their advantages and disadvantages, so we should give concrete analysis to concrete problems. © (2011) Trans Tech Publications. Source


Mu Z.,University of Science and Technology Beijing | Yao J.,University of Science and Technology Beijing | Zhang X.,Beijing Institute of Architecture Design
Applied Mechanics and Materials | Year: 2011

The long-span steel structure is usually used for the stadium, exhibition hall, airports, railway stations and other buildings, and these structures often have an intensive staff, stored supplies are relevant to people's livelihood and so on. If these buildings collapse under the fire, it may cause heavy casualties and property losses, so it's necessary to make a further research on its fire resistance performance. In this paper, make a fire scenario simulation to the Qingdao North Station main station by using fire simulation software FDS, in order to be sure the increased temperature of components. Then calculate stress of components under the most unfavorable fire temperature with finite element software "Midas" to make sure those components which need a fire protection. Finally, according to the analysis results to determine fire protection scheme, reduce unnecessary waste or local protection can not reach the requirements. This method of fire protection in the paper can provide reference for similar projects. © (2011) Trans Tech Publications, Switzerland. Source


Ding Y.,Harbin Institute of Technology | Law S.S.,Hong Kong Polytechnic University | Wu B.,Harbin Institute of Technology | Xu G.S.,Harbin Institute of Technology | And 3 more authors.
Engineering Structures | Year: 2013

A discrete force identification method based on average acceleration discrete algorithm is proposed in this paper. The method is formulated in state space and the external excitation acting on a structure is estimated with regularization method. A three-dimensional three-storey frame structure subject to an impact force and random excitations is studied respectively with numerical simulations. Uncertainties such as measurement noise, model error and unexpected environmental disturbances are included in the investigation of the accuracy and robustness of the proposed method. Experimental results from a seven-storey planar frame structure in laboratory are also used for the validation. The above results are also compared with those from two existing force identification methods, which are based on the Zeroth-Order-Hold (ZOH) discrete algorithm and the First-Order-Hold (FOH) discrete algorithm. Model of a fourteen-storey concrete shear wall building is studied experimentally with shaking table tests to further validate the proposed method. The shear wall structure has a two-storey steel frame on top with base isolation. The interface force in the isolation at the bottom of the steel frame during the seismic excitation is estimated with the proposed force identification method.Results from both numerical simulations and laboratory tests indicate that the proposed method can be used to identify external excitations and interface forces effectively based on the structural acceleration responses from only a few accelerometers with accurate results. The proposed method is capable to identify the dynamic load fairly accurately with measurement noise, model error and environmental disturbances. © 2013 Elsevier Ltd. Source

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