This award is an outcome of the NSF 08-519 program solicitation George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Research (NEESR) competition. This project will utilize the NEES equipment sites at Lehigh University and the University of Illinois at Urbana-Champaign. The goal of this NEESR-SD project is to develop, examine, implement, and demonstrate robust and accurate synchronization control tools that provide the capability to conduct real-time, multi-site experiment and simulation tests within the NEES framework. The ability to conduct real-time, multi-site experiments and simulation tests will allow NEES to reach its full potential as a distributed network of diverse equipment sites. Geographically-distributed, real-time testing between multiple NEES equipment sites will engage not just the diverse NEES experimental facilities, all with unique experimental and simulation capabilities, but in doing so will also bring together stakeholders with diverse backgrounds throughout earthquake engineering community. This innovative test technique will allow for larger and more complex experiments to be realized and provide experimental information from dynamic loading conditions previously not available. The project will develop simulation control algorithms necessary to implement real-time, multi-site experiments and examine the sensitivities of these algorithms to network delays, as well as measurement noise and variability and uncertainty in model parameters. A series of tests are planned using a small-scale system to develop and examine concepts and validate these methods with a fully physical shake table test. A user interface tool, based on the NEES Real-time Data Viewer (RDV), will be developed to facilitate conducting multi-site hybrid tests. Large-scale, real-time, multi-site experiments on full-scale NEES equipment will be conducted to demonstrate the application of these methods within the NEES network. An Internet-based education and outreach tool that accesses actual test data from the small-scale and large-scale tests will be developed to demonstrate the tools and methodologies developed within this research to the greater community. A training workshop will be held at the Lehigh NEES facility at the end of the project to promote the distributed use of NEES facilities through hybrid testing within both the NEES and the structural control communities. The results will be disseminated through NEES cyberinfrastructure, including NEEScentral, NEESforge and RDV.
One experiment, two laboratories – one at the University of Illinois the other at Lehigh University – running in real time and providing researchers the same results as if it had all been conducted at one site. A geographically distributed fully dynamic experiment was successfully conducted using multiple Network for Earthquake Engineering Simulation (NEES) equipment sites. The real-time hybrid test included two controllable 200 kN Magneto-Rheological (MR) fluid dampers, one located at NEES at Lehigh and the second at the University of Illinois, Urbana Champaign, implemented to reduce the seismic response of a simulated 3-story building model. The ability to conduct a dynamic test in real time at multiple sites will allow for larger more complex experiments in earthquake engineering to be imagined and conducted. The result will be a better understanding of complex structures and a safer built environment. The tools developed and validated in this project can be used to conduct future tests leveraging multiple equipment sites, such as shake table and large-scale test facilities, within the distributed NEES. This capability will allow researchers to conduct larger and more complex experimental verification of seismic protective systems more rapidly advancing the state of knowledge and acceptance of new concepts in seismic hazard mitigation. The development of the distributed simulation tools represents a solution to a complex problem and represented the first time a distributed real-time hybrid test was conducted between multiple NEES equipment sites. In the field of earthquake engineering, and more generally in structural dynamics and control, experimental verification is critical. For large structural systems, full-scale experimental tests may not be economically or practically feasible. Testing at multiple geographically distributed laboratories can optimize the use of distributed resources found in the Network for Earthquake Engineering Simulation (NEES) equipment facilities. Leveraging multiple equipment sites for dynamic tests conducted in hard real-time (where 1 second of the test is conducted in exactly 1 second) was made possible by addressing a number of challenges due to the hard real-time nature of the experiment and the inherent and unpredictable network delay associated with geographically distributed testing. This research provided a framework, sensitivity analysis, and series of tests conducted between the University of Connecticut, University of Illinois, and Lehigh University that demonstrated and verified the potential of geographically distributed testing. A workshop was held at the Lehigh NEES facility in October 2011 where the results of this project were disseminated to over 50 researchers working or interested in working in the area of real-time hybrid simulation.
