Low-order local modelling of structural nonlinearities

The present paper addresses the problem of characterising structural nonlinearities in view of system identification. A low-order local modelling strategy is proposed and encapsulated in a recently-introduced frequency-domain nonlinear subspace method for the estimation of model parameters. The complete methodology is first demonstrated using two academic examples, namely a Duffing oscillator and a five-degree-of-freedom system comprising two nonlinearities. The identification of an experimental beam involving nonlinear geometrical behaviour is finally addressed.