Various damper forces and dynamic excitation nonparametric identification with a double Chebyshev polynomial using limited fused measurements

Abstract

By introducting a double Chebyshev polynomial as a general nonparametric model for various nonlinear restorying forces (NRFs) and an updated observation equation, and with the help of an Updated Extended Kalman filter with unknown input (UEKF-UI) algorithm and a data fusion technology, a nonparametric identification approach for both NRFs at multiple locations and excitation for multi-degree-of-freedom (MDOF) lumped mass structures is presented. In order to investigate the generality of the proposed identification method, both numerical and experimental studies on different MDOF structure models equipped with a shape memory alloy (SMA) damper and/or a magnetorheological (MR) damper mimicking different types of nonlinearities that widely exist in practical engineering structures under unknown excitation are carried out. Identification results considering different initial estimation errors and measurement noise show that the NRF provided by different types of dampers at multiple locations, excitation and unmeasured dynamic responses can be identified nonparametrically with acceptable accuracy.