Output-only Identification of Loading and Modal Parameters in Dynamic Systems with Non-Gaussian Inputs

2019 ◽  
Author(s):  
T.J. ROGERS ◽  
K. WORDEN ◽  
R.S. MILLS ◽  
E.J. CROSS
Keyword(s):  
Dynamic Systems ◽  
Modal Parameters ◽  
Non Gaussian ◽  
Output Only

scholarly journals Output-Only Damage Detection of Shear Building Structures Using an Autoregressive Model-Enhanced Optimal Subpattern Assignment Metric

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2050
Author(s):  
Liu Mei ◽  
Huaguan Li ◽  
Yunlai Zhou ◽  
Dawang Li ◽  
Wujian Long ◽  
...  
Keyword(s):  
Dynamic Systems ◽  
Autoregressive Model ◽  
Structural Damage ◽  
Damping Ratio ◽  
Autoregressive Models ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Building Structures ◽  
Output Only ◽  
Shear Building

This paper proposes a novel output-only structural damage indicator by incorporating the pole-based optimal subpattern assignment distance with autoregressive models to localize and relatively assess the severity of damages for sheared structures. Autoregressive models can model dynamic systems well, while their model poles can represent the state of the dynamic systems. Structural damage generally causes changes in the dynamic characteristics (especially the natural frequency, mode shapes and damping ratio) of structures. Since the poles of the autoregressive models can solve the modal parameters of the structure, the poles have a close relationship with the modal parameters so that the changes in the poles of its autoregressive model reflect structural damages. Therefore, we can identify the damage by tracking the shifts in the dynamic system poles. The optimal subpattern assignment distance, which is the performance evaluator in multi-target tracking algorithms to measure the metric between true and estimated tracks, enables the construction of damage sensitive indicator from system poles using the Hungarian algorithm. The proposed approach has been validated with a five-story shear-building using numerical simulations and experimental verifications, which are subjected to excitations of white noise, El Centro earthquake and sinusoidal wave with frequencies sweeping, respectively; the results indicate that this approach can localize and quantify structural damages effectively in an output-only and data-driven way.

Output-Only Analysis for Modal Parameters Estimation of an Elastically Scaled Ship

2008 ◽  
Vol 52 (01) ◽  
pp. 45-56
Author(s):  
Giuliano Coppotelli ◽  
Daniele Dessi ◽  
Riccardo Mariani ◽  
Marcello Rimondi
Keyword(s):  
Life Prediction ◽  
Structural Response ◽  
Random Excitation ◽  
Parameters Estimation ◽  
Elastic Response ◽  
Modal Parameters ◽  
Practical Application ◽  
Scaled Model ◽  
Output Only ◽  
Ship Speed

The study of the ship structural response assumes an increasing importance as soon as the structures, characterized by much more lightness, are designed and built for faster vessels. This requisite implies a greater flexibility of the structures themselves, the elastic response of which has to be evaluated with accuracy in order to predict the dynamic behavior. In the present paper, a methodology for the identification of the modal parameters from the measurement of only the responses of a vibrating structure has been developed and applied to an elastically scaled model. This output-only technique is successfully applied to the segmented model of a real ship towed in the INSEAN linear basin. The broadband random excitation, provided by the loads exerted by an irregular sea pattern, induces a stochastic response of the model, which is monitored with accelerometers. The obtained results not only outline the parametric dependence of the modal properties on the ship speed, but also suggest a possible practical application of this technique for on-board structural monitoring and fatigue-life prediction.

scholarly journals Output-Only Modal Analysis Based on Improved Empirical Mode Decomposition Method

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Shiqiang Qin ◽  
Qiuping Wang ◽  
Juntao Kang
Keyword(s):  
Modal Analysis ◽  
Empirical Mode Decomposition ◽  
Modal Parameters ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Random Decrement Technique ◽  
Mode Decomposition ◽  
Frequency Components ◽  
Output Only ◽  
Emd Method

The output-only modal analysis for bridge structures based on improved empirical mode decomposition (EMD) is investigated in this study. First, a bandwidth restricted EMD is proposed for decomposing nonstationary output measurements with close frequency components. The advantage of bandwidth restricted EMD to standard EMD is illustrated by a numerical simulation. Next, the modal parameters are extracted from intrinsic mode function obtained from the improved EMD by both random decrement technique and stochastic subspace identification. Finally, output-only modal analysis of a railway bridge is presented. The study demonstrates the mode mixing issues of standard EMD can be restrained by introducing bandwidth restricted signal. Further, with the improved EMD method, band-pass filter is no longer needed for separating the closely spaced frequency components. The modal parameters extracted based on the improved EMD method show good agreement with those extracted by conventional modal identification algorithms.

scholarly journals Transmissibilty-Based Operational Modal Analysis for Flight Flutter Testing Using Exogenous Inputs

2012 ◽  
Vol 19 (5) ◽  
pp. 1071-1083 ◽  
Author(s):  
Christof Devriendt ◽  
Tim De Troyer ◽  
Gert De Sitter ◽  
Patrick Guillaume
Keyword(s):  
Modal Analysis ◽  
Frequency Domain ◽  
Experimental Modal Analysis ◽  
Operational Modal Analysis ◽  
Modal Parameters ◽  
Input Output ◽  
Output Only ◽  
Flutter Testing

During the recent years several new tools have been introduced by the Vrije Universiteit Brussel in the field of Operational Modal Analysis (OMA) such as the transmissibility based approach and the the frequency-domain OMAX concept. One advantage of the transmissibility based approach is that the ambient forces may be coloured (non-white), if they are fully correlated. The main advantage of the OMAX concept is the fact that it combines the advantages of Operational and Experimental Modal Analysis: ambient (unknown) forces as well as artificial (known) forces are processed simultaneously resulting in improved modal parameters. In this paper, the transmissibility based output-only approach is combined with the input/output OMAX concept. This results in a new methodology in the field of operational modal analysis allowing the estimation of (scaled) modal parameters in the presence of arbitrary ambient (unknown) forces and artificial (known) forces.

A new method to extract modal parameters using output-only responses

2005 ◽  
Vol 282 (1-2) ◽  
pp. 215-230 ◽  
Author(s):  
Byeong Hwa Kim ◽  
Norris Stubbs ◽  
Taehyo Park
Keyword(s):  
New Method ◽  
Modal Parameters ◽  
Output Only

Diagnosis and Estimation of Sensor Bias in Dynamic Systems Using Adaptive Techniques

2014 ◽  
Vol 678 ◽  
pp. 313-317
Author(s):  
R. Aarthi ◽  
R. Ananda Natarajan
Keyword(s):  
Dynamic System ◽  
Dynamic Systems ◽  
Projection Algorithm ◽  
Level System ◽  
Model Uncertainties ◽  
Nominal Model ◽  
Input And Output ◽  
Adaptive Technique ◽  
Output Only ◽  
Tank Level

The estimation and detection of sensor bias fault in a dynamic system is discussed. The development of more general methodology for diagnosing sensor bias faults in a dynamic system which depends on the state of the system is established. The non linearity in the system nominal model is assumed to be the function of input and output only, this note used the adaptive technique of model based system and Kaczmarz’s Projection algorithm. An Observer is designed to generate residual of the system which indicates the presence of fault and initiates to estimate unknown sensor bias in the presence of model uncertainties. The tank level system is considered for simulative example is presented to illustrate the methodology. The robustness, sensitivity and stability properties of the dynamic system were analyzed.

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