Application of a damping switch controller in semiactive electromagnetic seismic isolation systems

In this study, a practical damping switch control strategy for semiactive electromagnetic seismic isolation systems (SA-EMSIS) was introduced and evaluated. Two configurations were proposed: SA-EMSIS with linear stiffness and SA-EMSIS-NL with nonlinear stiffness. These systems can address the challenges posed by near-fault and far-field ground motions by dynamically activating a high-damping mode when isolation displacement exceeds a predefined threshold. Numerical simulations show that both SA-EMSIS and SA-EMSIS-NL effectively reduce isolation displacement, with SA-EMSIS-NL demonstrating superior performance by achieving significantly lower isolation acceleration. Shaking table experiments validated the feasibility of this control strategy, with close alignment between the experimental and theoretical results. The findings of this study highlight the potential of the proposed systems to improve seismic protection by balancing displacement suppression and acceleration control. This study contributes to the advancement of adaptive seismic isolation technologies and has practical implications for earthquake engineering.