Modal Identification by squared amplitude fitting methods

International audienceAs a result of the improvement in data acquisition systems, the recent trend in experimental modal analysis is to measure a larger number of frequency response functions (FRF) in order to obtain a more accurate description of the structure dynamic. However, Partial fraction and Rational fraction methods, both using frequency response functions, become more and more time consuming due to global parameters estimations methods (Curve Fitting algorithms divided in two successive steps). This explains why several parameter estimation techniques are currently developed. In fact, for linear systems, eigenvalues are the same for all frequency response measurements. In this paper, a new identification method, called Transfer Function Real Condensation (T.F.R.C), based on a squared fitting, is presented. This technique can be applied either to the amplitude response of each pick-up or to their sum. The capabilities of the T.F.R.C method are demonstrated on a few typical examples