Double least squares approach for use in structural modal identification

Ibrahim, S. R.

doi:10.2514/3.9296

Cited by 32 publications

(14 citation statements)

References 9 publications

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“…The damping ratio can be calculated by (8). Similar to the case of eigenvalues, numerical solution of eigenvectors has an error as well.…”

Section: Proposed Modification Of Itd Methodsmentioning

confidence: 99%

“…There are several published works on the development of ITD method, most of which discuss the approaches for improving the accuracy of identification (e.g., double least squares method [8] and correlation technique for ambient excitation with nonstationary white noise [9]). Nevertheless, the accuracy of identified damping ratio is often questionable, especially with noisy measurement [10].…”

Section: Introductionmentioning

confidence: 99%

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Practical Damping Identification of FAST Cable Suspension

Sun

Zhu

2014

Advances in Mechanical Engineering

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FAST focus cabin is suspended and driven by 6 parallel large span cables. Low stiffness of cables makes the cabin sensitive to disturbance and difficult to control. Structural damping then becomes a key factor that can improve control ability. Therefore, a reasonable damping estimation is important for system design. In this paper, a practical damping identification method is developed based on Ibrahim-time-domain algorithm. The method shows satisfied performance on accuracy and reliability in simulation test and is utilized in vibration experiments to identify damping ratios of both single cable model and FAST 3 m scale cable suspension model. Finally, a preliminary analysis of the damping properties is given out based on the results of identification.

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“…The damping ratio can be calculated by (8). Similar to the case of eigenvalues, numerical solution of eigenvectors has an error as well.…”

Section: Proposed Modification Of Itd Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Practical Damping Identification of FAST Cable Suspension

Sun

Zhu

2014

Advances in Mechanical Engineering

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“…In order to identify the structure dynamic parameters from the time domain data, at the early stage several techniques were proposed in the time domain on the basis of the experimentally measured responses of the structure: the Ibrahim method [17], the random decrement method [18], the least-squares complex exponential method [19], and the eigensystem realization algorithm [20]. Cattarius and Inman [21] used the beat phenomenon to characterize small differences.…”

Section: Output-only Methodsmentioning

confidence: 99%

The State-of-the-Art on Framework of Vibration-Based Structural Damage Identification for Decision Making

2017

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Abstract:Research on detecting structural damage at the earliest possible stage has been an interesting topic for decades. Among them, the vibration-based damage detection method as a global technique is especially pervasive. The present study reviewed the state-of-the-art on the framework of vibration-based damage identification in different levels including the prediction of the remaining useful life of structures and the decision making for proper actions. This framework consists of several major parts including the detection of damage occurrence using response-based methods, building reasonable structural models, selecting damage parameters and constructing objective functions with sensitivity analysis, adopting optimization techniques to solve the problem, predicting the remaining useful life of structures, and making decisions for the next actions. For each part, the commonly used methods were reviewed and the merits and drawbacks were summarized to give recommendations. This framework is aimed to guide the researchers and engineers to implement step by step the structure damage identification using vibration measurements. Finally, the future research work in this field is recommended.

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“…Ibrahim [17] notes that due to the exponential nature of Eq. (3.16), a small error in the eigenvalues α r will result in a large error in the calculated damping ratio in Eq.…”

Section: Accuracy Of Dic Measurements and Modal Parametersmentioning

confidence: 99%

“…Ibrahim [17] shows that using a double least squares approximation yields much more accurate damping ratios while preserving the accuracy of the natural frequencies and mode shapes. The system matrix A in Eq.…”

Section: Non-symmetric Response Matrices and The Double Least Squaresmentioning

confidence: 99%