RECURSIVE-IDENTIFICATION OF VIBRATING STRUCTURES FROM NOISE-CORRUPTED OBSERVATIONS .2. PERFORMANCE EVALUATION VIA NUMERICAL AND LABORATORY EXPERIMENTS

In the first part of this paper (Ben Mrad and Fassois, 1991), the problem of recursive structural dynamics identification from noise-corrupted observations was examined, and six approaches that properly account for the presence of noise in the experimental data and the fact that structural systems are inherently continuous-time were formulated. In this second part the relative performance characteristics of these approaches are investigated by using numerically simulated and laboratory data, the latter obtained from a free-free beam experiment. Structural systems with well separated and closely spaced modes are considered, and emphasis is placed on issues such as the achievable accuracy and resolution, rate of convergence, noise rejection, computational complexity, the need for model overdetermination, and the distinction of structural from "computational" vibrational modes. Unlike alternative methods, when properly used, the proposed approaches are shown to offer good performance with data corrupted at various noise-to-signal ratios.