Output-only damage detection in buildings using proportional modal flexibility-based deflections in unknown mass scenarios

Bernagozzi, Giacomo; Mukhopadhyay, Suparno; Betti, Raimondo; Landi, Luca; Diotallevi, Pier Paolo

doi:10.1016/j.engstruct.2018.04.036

Cited by 27 publications

(18 citation statements)

References 27 publications

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“…It estimates the state-space model: based on finite-time and noisy experimental data [14]. Over the years, the method has been extensively studied and used for modal parameters identification in various engineering problems, e.g., bridges-vehicle dynamic interaction (see, e.g., [10]), high-cycle fatigue of engines (see, e.g., [15]), machines construction optimization (see, e.g., [16]), and damage detection of engineering structures (see, e.g., [17]). The basic principle of ERA is to identify the system matrices A, B and C of order n (n is the number of significant equations to define the identified system) by means of measured free-vibration response.…”

Section: Eigensystem Realization Algorithm (Era)mentioning

confidence: 99%

Study on applicability of two modal identification techniques in irrelevant cases

Tomaszewska

Szafrański

2020

Archiv.Civ.Mech.Eng

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Study on applicability of two modal identification techniques in irrelevant cases is made in this paper. The following techniques are considered: peak picking based on correlation analysis (PP-CA), dedicated for ambient vibrations and eigensystem realization algorithm (ERA), formulated for free-decay vibrations investigation. Irrelevant cases are found when analyzed signals are different than recommended to a given technique. The study is conducted on examples of two real structures: masonry tower and steel railway bridge. Both cases are diverse in age, material, excitation and vibrations energy. The signals measured on the tower are suitable for the PP-CA technique (ambient vibrations), while the signals measured on the bridge are suitable for the ERA (free-decay vibrations). However, both methods have been applied to both systems. Natural frequencies, mode shapes and damping ratios are identified and the effectiveness of the irrelevant technique is assessed in relation to the results obtained by the relevant method in each case.

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Section: Eigensystem Realization Algorithm (Era)mentioning

confidence: 99%

Study on applicability of two modal identification techniques in irrelevant cases

Tomaszewska

Szafrański

2020

Archiv.Civ.Mech.Eng

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“…This method evolved from the Ho-Kalmann minimum realization problem, and estimates the modal parameters, i.e., frequencies, damping ratios and mode shapes, based on free-decay, finite-time and noisy experimental data [15,16]. The method has been extensively discussed and used in various mechanical and engineering problems, e.g., machine construction optimization (see, e.g., [17]), vehicle-bridge dynamic interaction (see, e.g., [18,19]), and the damage detection and technical condition assessment of structures (see, e.g., [20,21]). The input is a free-decay structural response to a certain action or initial condition.…”

Section: Eigensystem Realization Algorithm (Era)mentioning

confidence: 99%

Material Parameters Identification of Historic Lighthouse Based on Operational Modal Analysis

2020

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In the present paper, the identification of the material parameters of a masonry lighthouse is discussed. A fully non-invasive method was selected, in which the material properties were determined via numerical model validation applied to the first pair of natural frequencies and their related mode shapes, determined experimentally. The exact structural model was built by means of the finite element method. To obtain experimental data for the inverse analysis, operational modal analysis was applied to the structure. Three methods were considered: peak picking (PP), eigensystem realization algorithm (ERA) and natural excitation technique with ERA (NExT-ERA). The acceleration’s responses to environmental excitations, enhanced in some periods of time by sheet piling hammering or by sudden interruptions like wind stroke, were assumed within the analysis input. Different combinations of the input were considered in the PP and NExT-ERA analysis to find the most reasonable modal forms. A number of time periods of a free-decay character were considered in the ERA technique to finally calculate the averaged modal forms. Finally, the elastic modulus, Poisson’s ratio and material density of brick, sandstone and granite masonry were determined. The obtained values supplement the state of the art database concerning historic building materials. In addition, the numerical model obtained in the analysis may be used in further cases of structural analysis.

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“…It is well known that noise in modal measurements and errors due to modal truncation are the main variables that affect structural damage detection methods based on flexibility matrices [27][28][29][30]. For this reason, we evaluated the sensitivity of DFM when these variables were considered.…”

Section: Effects Of Limited Modal Information and Noisementioning

confidence: 99%

“…However, because it requires numerous sensors, it is not practical to use it on experimental models. Bernagozzi et al [30] developed a method for detecting damage in shear buildings when the mass of the system is not known or when there is very little information about it. is method estimates the modal deflections that are proportional to real deflections; after this estimation, the story drifts are evaluated to locate loss of stiffness.…”

Section: Introductionmentioning

confidence: 99%

“…Many damage detection methods based on structural flexibility have been developed. Despite their ability to estimate the flexibility matrix of a structure from measured lower-order modal shapes, these methods still suffer from modal truncation error, particularly on a complex structure with many higher modes that are not measured [27][28][29][30]. In this paper, we present the damaged flexibility matrix method (DFM), a new iterative damage detection method using the procedure developed by Baruch [31], to optimize and correct flexibility matrices from vibration measurements.…”

Section: Introductionmentioning

confidence: 99%

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Damaged Flexibility Matrix Method for Damage Detection of Frame Buildings

Oyola¹,

Fonseca²,

Rocha³

2020

Advances in Civil Engineering

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is study presents the damaged flexibility matrix method (DFM) to identify and determine the magnitude of damage in structural elements of plane frame buildings. Damage is expressed as the increment in flexibility along the damaged structural element. is method uses a new approach to assemble the flexibility matrix of the structure through an iterative process, and it adjusts the eigenvalues of the damaged flexibility matrices of each system element. e DFM was calibrated using numerical models of plane frames of buildings studied by other authors. e advantage of the DFM, with respect to other flexibility-based methods, is that DFM minimizes the adverse effect of modal truncation. e DFM demonstrated excellent accuracy with complete modal information, even when it was applied to a more realistic scenario, considering frequencies and modal shapes measured from the recorded accelerations of buildings stories. e DFM also presents a new approach to simulate the effects of noise by perturbing matrices of flexibilities. is approach can be useful for research on realistic damage detection. e combined effects of incomplete modal information and noise were studied in a ten-story four-bay building model taken from the literature. e ability of the DFM to assess structural damage was corroborated. Application of the proposed method to a ten-story four-bay building model demonstrates its efficiency to identify the flexibility increment in damaged structural elements.

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Output-only damage detection in buildings using proportional modal flexibility-based deflections in unknown mass scenarios

Cited by 27 publications

References 27 publications

Study on applicability of two modal identification techniques in irrelevant cases

Study on applicability of two modal identification techniques in irrelevant cases

Material Parameters Identification of Historic Lighthouse Based on Operational Modal Analysis

Damaged Flexibility Matrix Method for Damage Detection of Frame Buildings

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