Component system identification and state-space model synthesis

Sjövall, Per; Abrahamsson, Thomas

doi:10.1016/j.ymssp.2007.03.002

Cited by 26 publications

(37 citation statements)

References 15 publications

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“…Based on the acceleration responses at different stories and their phase differences obtained by the fast Fourier transformation [12] , mode shapes could be obtained from the ratios of the cross power spectral amplitudes at resonant frequencies between ambient vibration of the foundation and the stoerys to the selfpower spectral amplitude of the foundation vibration of the foundation [13] .…”

Section: Ambient Vibration Tests and Analysismentioning

confidence: 99%

Dynamic behavior of reinforced concrete frame structure during construction

Tian

2008

J. Cent. South Univ. Technol.

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The effects of concrete's time-variant elastic modulus, casting structural components, assembling temporary shoring framework system, and shock by operating construction equipment on dynamic behavior of the reinforced concrete frame structure during construction were investigated. The dynamic tests of an eight-storey reinforced concrete frame structure during full-scaled stages of the sixth storey construction cycle were carried out by ambient vibration. Natural frequencies, corresponding mode shapes and damping ratio were determined by power spectrum processing the tested signal data in frequency domain. The changes of frequencies, mode shapes and damping ratios at different construction stages were given. The results show that natural frequencies and modal damping ratios reach the maximum at stage of casting fresh concrete, especially for higher modes. Modal damping ratios at each construction stage are less than 5% of those during usage.

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Section: Ambient Vibration Tests and Analysismentioning

confidence: 99%

Dynamic behavior of reinforced concrete frame structure during construction

Tian

2008

J. Cent. South Univ. Technol.

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“…Su and Juang [41] introduced a different approach using first-order statespace systems. A similar approach was also taken by Sjövall and Abrahamsson [39], later used and elaborated by Liljerehn, see [18].…”

Section: Introductionmentioning

confidence: 95%

“…Here the state-space synthesis method developed by Sjövall and Abrahamsson [39] will be used. The method is briefly restated in Appendix A.…”

Section: Transmission Simulator In the State-space Domainmentioning

confidence: 99%

“…It should be stressed that for the state-space synthesis method introduced in [39] to succeed the identified statespace systems must fulfil some physical constraints [39]. Therefore, due to noise and other imperfections in the experimental data the system identification procedure must be constrained in most situations, which is usually performed in a post-processing procedure [17,40].…”

Section: Introductionmentioning

confidence: 99%

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State-Space Dynamic Substructuring with the Transmission Simulator Method

Gibanica

Nord

2019

Exp Tech

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Dynamic substructuring is a technique to simplify the analysis of complex structures. The vibrational problems of the constituent substructures are analysed and solved individually and their solutions are then assembled to form the global solution. In experimental dynamic substructuring, at least one of the constituent substructures is identified experimentally. The coupling interfaces are commonly simplified in such syntheses, which can result in poor prediction quality in many applications. The transmission simulator was introduced to address this problem. Transmission simulators are well-modelled parts attached to the interface of the substructures to be coupled. This allows for distributed interfaces and a relaxation of the coupling conditions by using the transmission simulator's analytical modes as a basis for the coupling equations, at the cost of adding a decoupling step to the substructuring problem. In this paper, the transmission simulator method is translated to the state-space substructuring domain. The methodology is applied to the Society for Experimental Mechanics' substructuring focus group's Ampair A600 test bed in form of experimental-analytical substructuring. The Ampair wind turbine's hub is used as the transmission simulator and is modelled with finite elements while the three blades, individually attached to the real hub, are experimentally identified. The three experimental blade hub systems are then coupled and two finite element hubs decoupled from the system, using the derived method. Finally, this system is compared to a directly measured hub with three blades by means of frequency response functions and modal properties.

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“…A SS system may be used as a physical representation of a machine (Lembregts, Leuridan, & Van Brussel, 1990;Petersen, Fraanje, Cazzolato, Zander, & Hansen, 2008;Sjövall & Abrahamsson, 2007, 2008, or as a general tool for specifying models that serve as predictors of the system (Lardies, 1998(Lardies, , 2008 either by itself or in a Condition Monitoring program, integrating Reliability Centered Maintenance and Remote Condition Monitoring (García, Schmid, & Conde, 2003;Pedregal, García, & Schmid, 2004). Especially related to this paper is Sjövall and Abrahamsson (2008), because they use also a continuous time SS model, though applied to the reconstruction of the interface forces acting between the unknown subsystem and its neighbour.…”

Section: Literature Reviewmentioning

confidence: 99%