| Recently, a Fast Hybrid Test (FHT) system has been developed at the University of Colorado as part of the George E. Brown, Jr. Network for Earthquake Engineering simulation program sponsored by the US National Science Foundation. This system further advances the current state-of-the-art in real-time pseudodynamic substructure tests with several unique features. It has a flexible system architecture that incorporates a general finite element analysis framework, and adopts an unconditionally stable time integration scheme and a Newton-type iterative technique with interpolation.; This report presents the real-time hybrid testing methodology developed for the FHT system and a mathematical model for a physical testing system. They are all implemented in Simulink.; In an effort to mitigate the effect of actuator delay, a discrete feed-forward compensation scheme has been developed, and a phase-lead compensator and feed-forward method, which are well known in the control area, are also implemented for the FHT system. The effectiveness of these schemes has been demonstrated through numerous simulations and real-time hybrid tests.; An analytical model has been developed in terms of a transfer function for a linearized test system. A detailed analysis of the performance of the system has been conducted with the developed system transfer function.; The influence of reaction frame flexibility has been investigated by real-time simulations, and a methodology to remove the inertia effect of a test structure from the measured restoring force has been proposed.; Finally, real-time hybrid tests have been conducted on single- and two-degree-of-freedom structures, and a column with axial, rotational, and translational degrees of freedom. Through these tests, it has been observed that the FHT system provides a superior performance. Further, it has been demonstrated that the three phase-lag compensation schemes and the inertia force correction scheme provide commendable performance. |
