Hybrid simulation for system-level structural response

• Differences between multiple hybrid simulation architectures are quantified.
• Issues with large analytical models in hybrid simulation are described.
• New gravity loading procedure for hybrid simulation is developed to reduce computation.
• Mitigation of oscillation and convergence issues in hybrid simulation are discussed.
• Large-scale hybrid simulation of RC frame is conducted and analyzed.

Hybrid simulations combine physical and analytical components into a single simulation to evaluate the response of a structure, often under seismic ground motion. This allows an experiment to be conducted in which structural components with complex response can be modeled experimentally and more well-known components can be represented within an analytical model. The coordination software UI-SimCor, developed by the MUST-SIM NEES facility at the University of Illinois at Urbana–Champaign, is a hybrid simulation tool which performs the dynamic analysis and other software and hardware coordination tasks for hybrid simulations. In many hybrid simulations, including those that have used UI-SimCor, analytical models with few effective degrees of freedom are typically used. In simulations where system-level behaviors and the response of the analytical components are of importance, a more detailed analytical system is needed. This changeover to a more complex analytical system and increase in general complexity of the hybrid simulation can cause various issues within the UI-SimCor framework. This study discusses the difficulties and issues that arise from having large and complex analytical substructures in hybrid simulation, and the effective mitigation or solutions to those problems.