Model-free Structural Hysteretic Force and Mass Identification using Limited Acceleration Measurement

Abstract

Structural hysteretic behavior provides a direct description on the initiation and development of structural damage and can be used for a quantitative evaluation of structural energy consumption under dynamic loadings. Most of the current vibration based structural identification approaches using structural modal parameters usually need the known mass information and are applicable for linear system only. In this study, an iterative structural hysteretic force modeled with a Chebyshev polynomial and mass identification approach using limited acceleration measurements under incomplete excitation condition with the help of Unscented Kalman Filter (UKF) is proposed and validated numerically. A multi-degree-of-freedom (MDOF) structure equipped with a Magneto-rheological (MR) damper mimicking nonlinear behavior is established. Acceleration response time history at limited DOFs of the structure under dynamic excitation at a certain DOF is employed to identify the structural hysteretic force and mass. The influence of the acceleration measurement noise and the initial assumption on the mass is also considered and the identified nonlinear restoring force of the MR damper is compared with it from its numerical constitutive model. The identified mass of each DOF of the nonlinear MDOF model is close to its true value. Numerical results shows that the hysteretic force and mass distribution are identified with acceptable accuracy by the direct use of partially known noise-polluted acceleration measurements.