Optimal sampling in the identification of a randomly excited structural system

The basic problem in experimental modal analysis of dynamic structural systems is the accurate extraction of modal parameters from the measured transfer function data. In this paper, the selection of the sampling interval for estimating the modal parameters from a randomly excited structure is considered. Emphasis is placed on the optimum design of uniform data sampling intervals when experimental constraints allow only a limited number of discrete-time measurements of the output from the continuous system, and the parameters of interest are natural frequencies, damping ratios, and time constant of the continuous system. Both the theoretical development and numerical examples are presented.