NON-PARAMETRIC IDENTIFICATION OF STRUCTURAL NONLINEARITY WITH LIMITED INPUT AND OUTPUT MEASUREMENTS

摘要

In this paper, an algorithm is proposed for the identification of model free nonlinearity in structural system with limited input and output measurements. The identification algorithm has a twostage procedure. In the first stage, location of nonlinearity is detected based on a two-step Kalman estimator for the equivalent systems and leastsquares estimation of the unknown excitations. In the second stage, structural nonlinearity is treated as 'fictitious unknown inputs' on the corresponding linear structures. By sequential Kalman estimator for the structural state vector and the least-squares estimation of the 'fictitious unknown inputs' , and unknown excitation, structural nonlinear characteristics can be quantified. Identification of a 6-storey nonlinear shear-frame structure with unmeasured excitation on the top is studied as numerical examples to demonstrate the effect of the proposed algorithm.