Time-variant structural parameter identification

Abstract

A new method based on windowed measured dynamic response is proposed for model updating of a time-variant structural system with unknown initial structural responses. A two phase identification algorithm is presented to identify both the initial structural responses and the time-variant structural parameter in each small time interval. Tikhonov regularization method is applied for the former while a modified adaptive regularization method is proposed to identify the structural parameter. The second method takes care of the initial model errors in updating the structural parameters. A multi-storey linear shear frame structure with and without nonlinear seismic isolators subject to seismic ground motion is used for the numerical study. A normally distributed initial model error of the structure is included. The proposed time-variant parameter identification method is found capable of identifying the time-variant parameters fairly accurately even with 10% measurement noise.