IDENTIFICATION OF TIME-VARYING STRUCTURES UNDER UNOBSERVABLE EXCITATION: AN OVERVIEW AND EXPERIMENTAL COMPARISON OF PARAMETRIC METHODS

structural identification, modal analysis. Abstract. This paper addresses the problem of parametric time-domain identification and dy-namic analysis for time-varying mechanical structures under unobservable random excitation. The available methods, based upon Time-dependent AutoRegressive Moving Average (TARMA) models, are reviewed and classified as unstructured parameter evolution, stochastic parame-ter evolution, and deterministic parameter evolution. The characteristics and relative merits of each class are outlined. A representative method from each class is then applied to the modelling of a time-varying (moving) laboratory structure consisting of a beam with a mass moving on it. The results are contrasted to “frozen-configuration ” (multiple experiment) base-line analysis. While all methods achieve more or less satisfactory performance and track the time-varying modal characteristics, the deterministic parameter evolution method exhibits the highest tracking accuracy and model parsimony (economy)