A PROCEDURE FOR THE IDENTIFICATION OF LINEAR AND NONLINEAR MULTI-DEGREE-OF-FREEDOM SYSTEMS

Most of the modern techniques for vibration analysis are based on the modal approach. However, when the systems under study are not lightly damped, so that there are significant cross-damping terms in the governing equations, when there are closely spaced natural frequencies or when non-linearities exist, then the modal approach is extremely limited. A number of techniques have been proposed to deal with these problems, but the methods tend to produce models which are subjective. In this paper, a generalized non-iterative approach in which spectral techniques are used is presented for the identification of multi-degree-of-freedom systems from input/output records. The method is suitable for the analysis not only of systems with significant cross-damping but also of highly coupled non-linear systems. The implementation of the technique is illustrated with two numerically simulated examples. © 1991.