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Communication Dans Un Congrès Année : 2014

Identification of loads of thin structures with the corrected Force Analysis technique: An alternative to spatial filtering regularization

Résumé

The Force Analysis Technique (FAT) is an experimental approach allowing the localization and quantification of loads on mechanical structures. This method is based on a local description of the structure's behavior, and is well established for thin structures (beams, plates, shells) and has recently been extended to complex 3D structures using finite element models. When applied to thin structures, the method is based on finite difference schemes to assess the spatial derivatives of the displacement field, that are valid when the discretization step is small as compared to the structural wavelength (typically more than 5 points by wavelength). The method is also known to necessitate a regularization step, a filtering in the wavenumber domain, that has been found experimentally to be necessary at low frequencies when there is more than 4 measurement points by structural wavelength. In other words, the regularization is necessary over the whole frequency range in which the finite difference-based estimators are valid. A correction of the finite difference estimators used in FAT has been recently proposed for beams and plates, under the acronym CFAT (for corrected FAT). This correction extends the frequency range in which the method is valid, up to a frequency corresponding to the Shannon's limit for the spatial sampling. The consequence is that CFAT can be used over a wide frequency range without any regularization, defined by a number of points by structural wavelength between 4 and 2. The aim of this communication is to show how this property can be used as an alternative to regularization. The size of the finite difference scheme can indeed be adapted as a function of the frequency, for a fixed measurement grid, to make the ratio wavelength over finite difference step between 2 and 4. This approach will be illustrated on an experimental case in which CFAT is used to identify active and passive loads on a vibrating plate.
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Dates et versions

hal-01057679 , version 1 (25-08-2014)

Identifiants

  • HAL Id : hal-01057679 , version 1

Citer

Q. Leclere, Frédéric Ablitzer, Charles Pezerat. Identification of loads of thin structures with the corrected Force Analysis technique: An alternative to spatial filtering regularization. ISMA, 2014, Leuven, Belgium. ⟨hal-01057679⟩
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