A GLOBAL SMOOTHING TECHNIQUE FOR FRF DATA FITTING

In previous studies, the method originally proposed by Dat and Meurzec for curve-fitting a modal model to frequency response functions has been demonstrated to be an extremely interesting means of analyzing data measured from structures which exhibit close modes and/or high level of damping i.e., high modal coupling. The aim of the research described in this article was to develop this technique in order to deal with multi-input multi-output systems, usually encountered in vibration testing, and to improve the numerical conditioning of the method by introducing orthogonal polynomials. Two practical applications using experimental data measured during vibration tests on cars are described in order to demonstrate the properties of this improved version and, when appropriate, occasional comparisons with other more conventional curve-fitting techniques are included.