Papers by Keyword: Health Monitoring

Abstract: A modal test was carried out on a 120m span concrete filled steel tubular arch bridge under operational conditions. The moving traffic load is considered as uncorrelated white noises at various points of the road surface and the test is of the type of multi-input multi-output (MIMO). The modal parameters are identified by Global Rational Fraction Polynomials (GRFP) method, a frequency domain method. In order to taking the mobile nature of the traffic load into consideration, a multi-input NExT method is utilized to retrieve the frequency response function needed by GRFP. A proof of the NExT method in the case of multi-input case is also provided in this paper.

Abstract: Bridge Health Monitoring System (BHMS) is a combination of sensor monitoring technique and network communication technique, in charge of working status inspection and health detection and alarm via filed data, providing a solid safeguard for the well-balanced operation of the bridge as well as the security of people’s life and property. In this paper, it offers a solution plan which based on S2SH architecture. It describes the design and implementation process of the bridge structural health monitoring system, by using Extjs which brings better user experience.

Abstract: Kolmogorov entropy theory was introduced into this paper for time series of one-parameter maximum likelihood estimation of the entropy K, combined with practical applications to aeroengine health monitoring. K entropy value was used to describe the disorder degree of aeroengine parts performance parameters, analyzing the health status and evolutive trend of aeroengine components. Optimization base on K entropy was used to analyze muli-parameter time series trend of K entropy, according to preferred status indicator changes analyzes the overall health of aeroengine. Experimental demonstration on the actual flight data can be more accurately reflected the health of aeroengine,have some significance to fault diagnosis and repair of aeroengine

Abstract: Ongoing bridge collapse in both at home and abroad, makes people pay increasingly attention to bridge health monitoring. Bridge health monitoring which based on the GPS multiple antenna technology, GPRS wireless communications technology and so on, warning systems including GPS deformation monitoring subsystem, multiple antennas and safety assessment subsystem structure, can achieve bridge deformation data automatic acquisition, processing, analysis and structural safety evaluation and Internet remote transmission, automatic alarm function. Compared with the traditional method, the system has high accuracy and good data continuity, convenient operation, less investment etc, also has good social and economic benefits and broad application prospect.

Abstract: The microwave interferometer used in the present study is capable of multiple-point displacement measurements. In this paper, a general review of the principle and capacity of such an instrument is given. The vertical displacements of the Ai-Lan bridge corresponding to ambient vibration due to traffic loads are remotely monitored . Several modal shapes of the whole bridge are precisely identified by linking the mode shapes of seven sequential measurements.

Abstract: Cross Correlation Function Amplitude Vector(CorV) is a method of damage detection which is based on random vibration .In this paper, CorV is introduced in the damage detection of historic timber structure according to the characteristics of structure and damage.Meanwhile,the research has been done. CorV of structural damage before and after the change has been expressed that is based on Cross Correlation function amplitude Vector Criterion(CVAC) .Results show that there is a remarkable decrease of CVAC among the CorVs between damaged and intact structures.Damage locations can be determined through the relative change of CorVs which is before or after the damage of the structure . A basis can be provided for the damage of buildings and the ancient structure protection through this paper.

Abstract: Quayside container crane is a main lifting machinery in the seaports, which plays an important role in the trade contacts and transportation. This paper aims at the present security condition of quayside container crane, discusses the health monitoring problem of quayside container crane and introduces the health monitoring technology based on fiber bragg grating sensor, providing theoretical foundation for improving security condition of crane.

Abstract: An optimal damage detection sensor placement methodology is presented. The techniques utilize a Particle Swarm Optimization (PSO) algorithm. The proposed method is iterative in nature and it permits the use of incomplete measurements. Also, it allows diversity of damage detection algorithms to be used to generate the PSO required fitness function. However, in this work Linear Matrix Inequalities are used as the damage detection schemes. Computer simulations of a cantilevered beam will be used to demonstrate the effectiveness of the methodology.

Abstract: Bridge plays an important role in modern transportation. Once it is damaged, there will be great loss. So assessment of bridge state has become more and more important in modern society. Ambient around bridge always are very complex and bridge is affected by many factors. So in all response of bridge, noise and useful signals mixed together. The noise generally includes temperature effect, wind load effect, live-load effect, and so on. In order to get the useful signals we must separate the live-load effect from the total effect by using multi-scale analysis firstly. EMD brought a new method for multi-scale analysis and it is superior to wavelet to some extent. But it has some shortcomings also. In order to improve the performance of the EMD further, EEMD is introduced to extract live-load effect of bridge. The practical and simulation results verified the feasibility of the new method based on EEMD and the results is much better than those based on wavelet.

Abstract: Stress guided waves in the sonic and ultrasonic regime are acknowledged as a powerful too lto inspect pipes in a non-invasive manner.A key point of the inspection procedure is related to the dispersive behavior of guided waves, that for agiven pipe is defined by the so-called dispersion curves. Such behavior, is generally predicted bymeans ofanalytical formulations. However, when the geometry of the pipe cross-section is not axially symmetric,such as in the presence of an open internal crack running along the pipe length, analytical formulations fail. Here, the computation of the guided waves properties for such a scenario is addressed via a SemiAnalytical Finite Element (SAFE) formulation in which the open crack is modeled at the mesh level.Different crack depths are considered and their effect on the waves dispersion curves are highlighted.The results could be of interest in pipeline inspection and monitoring.