CUMULANT-BASED MODAL PARAMETER EXTRACTION OF STRUCTURES

This paper describes a nonlinear deterministic estimator based on cumu lants for the extraction of modal parameters. The signal analysed is c omposed of multiple exponentially damped real sinusoids in unknown add itive noise. Cumulants reduce significantly the effects of noise and a re also an efficient way of compressing the sampled data. In modal ana lysis a sensor may be unable to detect some modes of vibration due to its location. Cumulants estimated from real data sampled at different locations and instances are added directly together. This average cumu lant function will contain the eigenvalues for all excited modes of vi bration. Finding the frequencies and corresponding damping factors is therefore reduced to solving a single average cumulant function. The p erformance of the proposed estimator is examined and compared with the Eigensystem Realization Algorithm via simulations.