Time-Varying Output-Only Identification of a Cracked Beam

Bellino, Andrea; Garibaldi, Luigi; Marchesiello, Stefano

doi:10.4028/www.scientific.net/kem.413-414.643

Cited by 9 publications

(17 citation statements)

References 7 publications

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“…The first step of the procedure is the identification of the time-varying natural frequencies by means of the ST-SSI method [6], which is able to obtain a value of frequency for all the time instants, by applying the classical subspace methods in successive signal windows. This method is based on Van Overschee's work but it is applied to time-varying systems.…”

Section: Time-varying Frequenciesmentioning

confidence: 99%

“…On the other side, time-varying systems are usually analyzed with parametric methods [5] or techniques extended from the linear time-invariant case, such as the "frozen technique" [6]. In particular, for the former ones, the typical case studied is the Duffing oscillator [7], but it is impossible to find a theoretical relationship linking the natural frequency, the signal amplitude and the nonlinearity when the polynomial order defining the nonlinearity is larger than 3 [7].…”

Section: Introductionmentioning

confidence: 99%

“…The idea behind this article is to connect the usual approaches applied for the time-varying systems (in particular the method called ST-SSI [6]), with a method for the estimation of the nonlinear frequency in a generic system. This procedure allows obtaining the nonlinearity if a free decay response is analyzed.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental Dynamic Analysis of Nonlinear Beams under Moving Loads

Bellino

Marchesiello

Garibaldi

2012

Shock and Vibration

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Abstract.It is well known that nonlinear systems, as well as linear time-varying systems, are characterized by non-stationary response signals. In this sense, they both show natural frequencies that are not constant over time; this variation has however different origins: for a time-varying system the mass, and possibly the stiffness distributions, are changing over time, while for a nonlinear system the natural frequencies are amplitude-dependent. An interesting case of time-varying system occurs when analyzing the transit of a train over a railway bridge, easily simulated by the crossing of a moving load over a beam. In this case, the presence of a nonlinearity in the beam behaviour can cause a significant alteration of the modal parameters extracted from the linearized model, such that the contributions of the two effects are no more distinguishable.For this study, some reinforced concrete beams have been tested in the framework of a vast project: these beams show a clear softening nonlinear behaviour, well detectable when the excitation is produced by a hammer (free response). If the passage of a carriage is considered, moreover, the variation of natural frequencies is always larger than expected because of this softening nonlinearity.The article first analyzes theoretically the two effects on the natural frequencies of a simply supported beam, then a numerical and an experimental tests are presented. The identification procedure is conducted with a linear algorithm called ST-SSI, which has been demonstrated to be appropriate for the analysis of non-stationary signals, in particular in presence of moving masses. The article shows that the nonlinear contribution can be well estimated by using this linear tool but, on the contrary, when also moving masses are present, it is difficult to separate the nonlinear effects from the time varying ones.

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Section: Time-varying Frequenciesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Dynamic Analysis of Nonlinear Beams under Moving Loads

Bellino

Marchesiello

Garibaldi

2012

Shock and Vibration

Self Cite

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“…Bilello and Bergman (2004) provided an analytical tool for the analysis of a damaged beam under a moving mass. Bellino et al (2009) presented a time-varying identification method to detect a crack in a beam with a moving mass. Considering that natural frequencies of real structures are affected by environmental conditions such as the mass and the velocity of the train, Bellino et al (2010) established the relationship between the natural frequencies and the load characteristics.…”

Section: Introductionmentioning

confidence: 99%

Damage Detection Using Measurement Response Data of Beam Structure Subject to a Moving Mass

Lee

Eun²

2015

Lat. Am. j. solids struct.

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The moving load problem is divided into two typical types: moving force and moving mass. The moving mass problem includes the time-varying mass effect. This work considers damage detection of the beam structure subject to a moving load including the inertia effect based on the only measurement data from strain gages and accelerometers without any baseline data. This experiment compares the feasibility of damage detection methods depending on the measurement sensors of strain gages and accelerometers. The measurement data are transformed to the proper orthogonal modes (POMs) in the time domain and the frequency domain, respectively. The magnitude of the moving mass and its velocity are also evaluated as test variables in this experiment. It is shown in the beam tests that the measured strain data can be more explicitly utilized in detecting damage than the acceleration data, and the mass magnitude and its velocity affect the feasibility of damage detection.

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“…Bilello and Bergman [1] provided an analytical tool for the analysis of a damaged beam under a moving mass. Bellino et al [2] presented a time-varying identification method to detect a crack in a beam with a moving mass.…”

Section: Introductionmentioning

confidence: 99%

Damage detection by a moving mass on beam structure

Ahn¹,

Lee²,

Cho³

et al. 2015

Advanced Science and Technology Letters

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Abstract. The moving mass acts on beam structure as inertia force and includes the time-varying mass effect. This work considers damage detection of the beam structure subject to a moving mass based on the only measurement data from a strain gage and an accelerometer. This experiment investigates the feasibility of damage detection by the measurement of the inertia force and the output responses without any baseline data. The measurement data are transformed to the proper orthogonal modes (POMs) in the time domain. It is shown that the proposed method can be practically utilized by reducing the effect of the external noise.

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Time-Varying Output-Only Identification of a Cracked Beam

Cited by 9 publications

References 7 publications

Experimental Dynamic Analysis of Nonlinear Beams under Moving Loads

Experimental Dynamic Analysis of Nonlinear Beams under Moving Loads

Damage Detection Using Measurement Response Data of Beam Structure Subject to a Moving Mass

Damage detection by a moving mass on beam structure

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