Chapter 32 Real Time Hybrid Simulation with Online Model Updating on Highly Nonlinear Device Ge Ou and Shirley J. Dyke Abstract Hybrid Simulation (HS) and Real Time Hybrid Simulation (RTHS) are recognized as powerful techniques for civil infrastructure assessment. Typically in HS/RTHS, a critical component is isolated as the physical component in the simulation, while the remainder of the structure is modeled numerically. This approach enables response evaluation on both local and global level. Broadening the applications that would like to use HS and RTHS requires that we examine more complex structural systems. When multiple components in the structural system have the same design and contribute roughly equally to the response, it may be difficult to select the most appropriate physical component. However, modeling errors in those structural components that reside in the numerical component can influence the accuracy of the global responses. Model updating based on the responses of the physical component for determining the model parameters will reduce the influence of the modeling errors. Advances in online system identification techniques and their application to more complex structural models, enables the option of incorporating online model updating into HS/RTHS. Through a simplified case study, we explore the feasibility of HS/RTHS with model updating (HSMU/RTHSMU). A two story steel frame equipped with two identical magnetic-rheological (MR) dampers. In RTHS, the first story MR damper is loaded as the physical component and the remainder of the structure, including the frame and the second MR damper, is numerically modeled. Simulation and conventional RTHS response are considered. In each case the second story MR damper model uses one initial parameter set, which is then updated online using identified parameters based on the physical component (RTHSMU). Online model updating is then investigated using a validation signal, and the fidelity and advantages of RTHSMU are discussed. Keywords Real time hybrid simulation • Online model updating • BoucWen model • MR damper model • Constrained unscented Kalman filter 32.1 Introduction In contrast to conventional testing methods and pure numerical simulation, in hybrid simulation (also known as pseudodynamic testing or dynamic sub-structuring), the critical/hard to model component is isolated in the physical part while the rest is in the numerical part, with boundary condition secured by actuators linked between the two parts [1–3], both global performance of the infrastructure such as drift, failure mechanism, progressive collapse and local behavior includes hysteresis, local failure, and energy dissipation can be investigated [4–6]. When rate dependent component is involved, the test has to be done in real time scale. The applications of RTHS start with successfully examples in evaluating vibration control performance of damper devices and base isolators [7–9] and are further expanded to applications of evaluating structural components. However, difficulties on the selection of the physical component appear when multiple components with the same design contribute equally to the structural response. With improvements on identification convergence rate and its robustness regards to noise, model uncertainties, and initial conditions, online system identification algorithms are made feasible to experimental applications. One popular class of system identification methods can be implemented in real time is the Kalman filter family. Initially started in linear system, the Extended Kalman Filter (EKF) and the Unscented Kalman Filter (UKF) were developed subsequently for nonlinear system, where EKF optimizes the linearization approximation of the system through Jacobian matrix while UKF uses the G. Ou ( ) Lyles School of Civil Engineering, Purdue University, West Lafayette, IN 47906, USA e-mail: gou@purdue.edu S.J. Dyke School of Mechanical Engineering, Lyles School of Civil Engineering, Purdue University, West Lafayette, IN 47906, USA © The Society for Experimental Mechanics, Inc. 2016 J. De Clerck, D.S. Epp (eds.), Rotating Machinery, Hybrid Test Methods, Vibro-Acoustics & Laser Vibrometry, Volume 8, Conference Proceedings of the Society for Experimental Mechanics Series, DOI 10.1007/978-3-319-30084-9_32 343
RkJQdWJsaXNoZXIy MTMzNzEzMQ==