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Modal testing

About: Modal testing is a research topic. Over the lifetime, 4047 publications have been published within this topic receiving 64772 citations.


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Journal ArticleDOI
TL;DR: In this paper, the authors presented a methodology to analyze the influence of the foundation or supporting structure on the rotor-bearings system performance, using the Finite Elements Method (FEM) to model the rotor.

64 citations

Journal ArticleDOI
TL;DR: In this paper, the temperature-induced variations of measured modal frequencies of steel box girder for a suspension bridge using long-tem monitoring data are investigated in detail and the analysis results reveal that the identified modal frequency using IWCM provide an effective indication for changes of the bridge due to the ambient temperature variations.
Abstract: This paper addresses the temperature-induced variations of measured modal frequencies of steel box girder for a suspension bridge using long-tem monitoring data. The output-only modal frequency identification of the bridge is effectively carried out using the Iterative Windowed Curve-fitting Method (IWCM) in the frequency-domain. The daily and seasonal correlations of frequency-temperature are investigated in detail and the analysis results reveal that: (i) the identified modal frequencies using IWCM provide an effective indication for changes of the bridge due to the ambient temperature variations; (ii) temperature is the critical source causing modal variability, and there is an overall decrease in modal frequency with temperature for all the identified modes; (iii) the random variations in measured modal frequencies mainly arise from the identification algorithm due to the nonstationary loadings, which can be effectively eliminated using multi-sample averaging technique; (iv) the daily averaged modal frequencies of vibration modes have remarkable seasonal correlations with the daily averaged temperature and the seasonal correlation models of frequency-temperature are suitable for structural damage warning if future seasonal correlation models deviate from these normal models.

64 citations

Journal ArticleDOI
TL;DR: In this article, combined modal testing of footbridges is explored using two case studies: a steel arch footbridge with spans of 75.2 m and 30.3 m and a concrete stress-ribbon footbridge having spans of 30 m and 28 m.
Abstract: In combined vibration testing, an artificial, measured force is used in operational conditions. This requires the identification of a system model that takes both the measured and the operational excitation into account. Advantages with respect to the classical operational modal analysis approach are the possibility of obtaining mass-normalized mode shapes and the increase of the excitation level and its frequency content. An advantage with respect to the classical experimental modal analysis approach, where the ambient excitation is not modeled, but considered as disturbing noise, is the possibility of using excitation levels that are of the same amplitude, or even smaller, than the ambient excitation levels. In this paper, combined modal testing of footbridges is explored using two case studies: a steel arch footbridge with spans of 75.2 m and 30.3 m and a concrete stress-ribbon footbridge with spans of 30 m and 28 m. The comparison of the modal parameters (eigenfrequencies, damping ratios, mode shapes,...

64 citations

Journal ArticleDOI
TL;DR: In this paper, the modal variability due to changing traffic loading is investigated through post-processing of the data in each section in both amplitude and frequency domains, and the results indicate that the natural frequencies of the global modes can exhibit as much as 1% variation within a day.
Abstract: The traffic-induced variability in the dynamic properties of a cable-stayed bridge is investigated using ambient vibration measurements. Under a relatively steady wind and temperature environment, the ambient vibration test was conducted on the bridge with normal traffic conditions and totally 24 h acceleration response time histories were recorded. These data are divided into 12 sections with each data section containing 2 h measurements. Thereby the modal variability due to changing traffic loading is investigated through post-processing of the data in each section in both amplitude and frequency domains. The result indicates that the natural frequencies of the global modes can exhibit as much as 1% variation within a day. The modal amplitudes of each mode as well as the modal deflection at each measurement position vary insignificantly. The damping ratios however are sensitive to the vibration intensity, especially when the deck vibration exceeds a certain level. Copyright © 2002 John Wiley & Sons, Ltd.

63 citations

Journal ArticleDOI
TL;DR: In this paper, a real-time kinematic (RTK) global positioning network system (GPS) was used to measure the low-frequency vibration of a medium span suspension bridge.

63 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202367
2022164
202141
202059
201967
201878