Indirect Measurement of Multiple Excitation Force Spectra by FRF Matrix Inversion: Influence of Errors in Statistical Estimates of FRFs and Response Spectra
Abstract:In this paper, the indirect measurement of multiple broad band force spectra by FRF matrix inversion, using popular FFT-based spectral analysis techniques, is considered. Since inverse force measurements are often met with some mistrust because of their sensitivity to small, more or less unavoidable errors in measured data, it is attempted to clarify various possible error mechanisms. To this end, the influence of statistical errors in the estimation of FRFs and response spectra on inversely determined force spectra was investigated. Based on the knowledge of main characteristics of each of the potential error types, models were derived to characterise the propagation to, and the distribution over, computed force spectra. In contrast to work reported on in the literature, these models permit to characterise errors on any individual spectrum. The derived error models were validated in numerical simulations on a set of IIR filters approximating the input-output behaviour of a simply supported plate. Finally, they were shown to predict meaningful error bounds in a laboratory experiment where 2 forces acting on a suspended plate were to be identified.
Document Type: Research Article
Publication date: July 1, 1999
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- Acta Acustica united with Acustica, published together with the European Acoustics Association (EAA), is an international, peer-reviewed journal on acoustics. It publishes original articles on all subjects in the field of acoustics, such as general linear acoustics, nonlinear acoustics, macrosonics, flow acoustics, atmospheric sound, underwater sound, ultrasonics, physical acoustics, structural acoustics, noise control, active control, environmental noise, building acoustics, room acoustics, acoustic materials, acoustic signal processing, computational and numerical acoustics, hearing, audiology and psychoacoustics, speech, musical acoustics, electroacoustics, auditory quality of systems. It reports on original scientific research in acoustics and on engineering applications. The journal considers scientific papers, technical and applied papers, book reviews, short communications, doctoral thesis abstracts, etc. In irregular intervals also special issues and review articles are published.
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