Substructure Shake Table Testing with Force Controlled Actuators

Abstract

Real-time hybrid simulation (RTHS) has emerged as a feasible and economical means for seismic performance assessment of structural systems. It has been successfully applied to study the system-level response, combining experimental and computational substructures. However, existing substructure techniques are limited to interface boundaries where the influence of unbalanced forces are not significant; because existing formulation procedures and experimental loading are both displacement-based, unbalanced forces are inevitable in conventional RTHS. In some cases (e.g., testing of extremely rigid specimens, soil-structure boundaries), force equilibrium becomes more critical than displacement compatibility. To accommodate such conditions, a force-based approach is essential and has to be developed in RTHS. This study presents substructure shake table testing as a case study of forcebased RTHS. A four-story shear structure is divided into two substructures. The first story is tested on a shake table while the rest of the structure is computationally simulated. The interaction between the experimental and computational substructures is addressed such that the measured acceleration at the top floor in the experimental substructure is used as the base input to the computational structure while computed base shear in the computational substructure is fed back to the experimental substructure through a force-controlled actuator. As such, the overall simulation is performed at real-time with force-controlled actuators. This study presents the underlying theories of the substructure shake table test method, centralized actuator control and preliminary numerical simulations.

Predictive stability indicator: a novel approach to configuring a real‐time hybrid simulation

“…In this case, the shake table serves as the transfer system to meet the boundary conditions at interface. Some implementations of RTHS with similar partitioning approach can be found in . To assess the sensitivity of possible partitioning choices, the virtual PSI framework shown in Figure is adopted.…”

Digital twins for the underwater shake table array facility

“…They provide an effective way to subject structural components, substructures, or entire structural systems to dynamic excitation similar to those induced by real earthquakes. 11 The components of the shake table are separated into four parts: the platform and supporting system, the actuation system, the hydraulic power system, and the control system. The platform and supporting system is used to support the test specimen and prevent damage of the shaking table caused by the excessive weight; the actuation system converts the pressure of oil into mechanical energy to drive the shaking table make a movement; the hydraulic power system converts the electric energy into pressure energy; and the control system is used to precisely reproduce the motions.…”

“…Since modern engineering structures are huge and the working condition is complicated, for seismic engineering experimental research, a large servo‐hydraulic shaking table system is an indispensable tool. They provide an effective way to subject structural components, substructures, or entire structural systems to dynamic excitation similar to those induced by real earthquakes 11 …”