This seminar presents an overview of the research program on effective force testing (EFT) at the Johns Hopkins University. EFT is an experimental method that directly applies input dynamic forces to test structures using hydraulic actuators. Though EFT has several advantages over shake table testing and hybrid simulation, it has not been thoroughly explored due to technical challenges in force control such as stability, robustness and control-structure interaction. Recent efforts at the Johns Hopkins University proved that a loop shaping control approach is effective in force control, compensating for the control-structure interaction and suppressing the oil-column resonance of hydraulic actuators. Furthermore, the loop shaping force feedback controller extents the frequency bandwidth up to 25 Hz or even higher. Feasibility of EFT with the loop shaping controller was experimentally validated with linear and nonlinear test structures. The presentation covers issues of force control, experimental validation, and potential applications of EFT. In addition, ongoing efforts on EFT such as multi-degrees-of-freedom EFT and substructure EFT are presented.
Dr. Nakata is an Assistant Professor in the Department of Civil Engineering at the Johns Hopkins University. He holds a B.S. and M.S. in Civil Engineering (Kyoto University, Japan), and a Ph.D. in Civil and Environmental Engineering (University of Illinois at Urbana-Champaign). His research interests include experimental methods for structures, structural control, structural system identification, and earthquake engineering. He is a recipient of the 2010 National Science Foundation Faculty Early Career Development (CAREER) award.
Credits and References
Department of Civil Engineering
Johns Hopkins University
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