Real Time Estimation of Modal Parameters and Their Quality Assessment

Uhl, Tadeusz; Petko, Maciej; Karpiel, Grzegorz; Klepka, Andrzej

doi:10.1155/2008/304362

Cited by 12 publications

(5 citation statements)

References 8 publications

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“…The progression of variable airspeeds in a hypersonic flutter test does not satisfy the assumption of a stationary stochastic process, which is the theoretical basis of these damping methodologies. Some researchers [27,28] have successfully solved modal identification for nonstationary measured signals by using time-domain modeling methods such as ARMA or TVAR, which are mathematically equivalent to the system stability criterion discussed here.…”

Section: Hypersonic Flutter Analysis Frameworkmentioning

confidence: 99%

Novel Nonstationarity Assessment Method for Hypersonic Flutter Flight Tests

Zheng

Liu

Duan

2018

Mathematical Problems in Engineering

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Hypersonic aircraft have been rapidly developed in recent years both theoretically and experimentally. Aerothermoelastic simulation is very challenging due to its inherent complexity, but physical tests are a workable approach. Flutter tests with variable speed are a popular alternative to hypersonic tests which provide nonstationary structural response data. This paper proposes a nonstationarity assessment method based on energy distribution in the time-frequency domain. The proposed method reveals the nonstationarity level corresponding to the appropriate modal identification algorithm or flutter boundary prediction (FBP) method. Several classic flutter criteria are utilized to build a hypersonic aircraft FBP framework. Numerical simulation and experimental applications demonstrate the effectiveness and feasibility of the proposed method, which facilitates accurate flutter predictions for the subcritical turbulence response during hypersonic flutter flight.

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Section: Hypersonic Flutter Analysis Frameworkmentioning

confidence: 99%

Novel Nonstationarity Assessment Method for Hypersonic Flutter Flight Tests

Zheng

Liu

Duan

2018

Mathematical Problems in Engineering

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“…Figure 4 shows the stationary behaviour of the Gaussian white noise excitation in the time domain. However, if one considers only a small part of this signal, the stationary and broadband behaviour is not so Time (s) ×10 9 Excitation in frequency domain obvious. This is particularly visible in the combined timefrequency domain where the energy distribution of the white noise signal varies with time and frequency from high to near zero amplitudes.…”

Section: Input Excitation For Analysis Of Time-variant Systemsmentioning

confidence: 99%

“…The method presented in [8] is an evolutionary approach and is also used for modal identification. Timescale approaches have been used also for online identification procedures based on adaptive wavelets [9][10][11][12][13]. An overview of different wavelet-based approaches can be found in [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Wavelet-Based Frequency Response Function: Comparative Study of Input Excitation

Dziedziech

Staszewski

Uhl

2014

Shock and Vibration

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Time-variant systems can be found in many areas of engineering. It is widely accepted that the classical Fourier-based methods are not suitable for the analysis and identification of such systems. The time-variant frequency response function—based on the continuous wavelet transform—is used in this paper for the analysis of time-variant systems. The focus is on the comparative study of various broadband input excitations. The performance of the method is tested using simulated data from a simple MDOF system and experimental data from a frame-like structure.

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“…The time-frequency analysis includes methods based on the short-time Fourier transform, Wigner-Ville distribution and many other approaches based on the so-called Cohen's class distributions [3,4]. The time-scale approaches are based on the application of the wavelet analysis and include methods for damping estimation [5][6][7], identification of nonlinear systems [8], estimation of instantaneous frequency [9], methods based on adaptive wavelets [10,11] and methods based on the transfer function [12]. Good overviews of wavelet-based methods for time-variant systems are given in [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Wavelet-based analysis of time-variant adaptive structures

Dziedziech

Nowak

Hasse

et al. 2018

Phil. Trans. R. Soc. A.

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Wavelet analysis is applied to identify the time-variant dynamics of adaptive structures. The wavelet-based power spectrum of the structural response, wavelet-based frequency response function (FRF) and wavelet-based coherence are used to identify continuously and abruptly varying natural frequencies. A cantilever plate with surface-bonded macro fibre composite-which alters the structural stiffness-is used to demonstrate the application of the methods. The results show that the wavelet-based input-output characteristics-i.e. the FRF and coherence-can identify correctly the dynamics of the analysed time-variant system and reveal the varying natural frequency. The wavelet-based coherence can be used not only for the assessment of the quality of the wavelet-based FRF but also for the identification.This article is part of the theme issue 'Redundancy rules: the continuous wavelet transform comes of age'.

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Real Time Estimation of Modal Parameters and Their Quality Assessment

Cited by 12 publications

References 8 publications

Novel Nonstationarity Assessment Method for Hypersonic Flutter Flight Tests

Novel Nonstationarity Assessment Method for Hypersonic Flutter Flight Tests

Wavelet-Based Frequency Response Function: Comparative Study of Input Excitation

Wavelet-based analysis of time-variant adaptive structures

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