A semi-explicit integration algorithm with controllable numerical damping for real-time hybrid simulation

Real-time hybrid simulation (RTHS) is a cost-effective experimental method for evaluating the dynamic behavior of structures. In the numerical computation component of RTHS, the use of efficient, accurate, and stable integration algorithms is critical for its effective execution. This study presents a single-step semi-explicit integration algorithm SSE-alpha, designed to enhance the precision and robustness of numerical computations in RTHS. The numerical properties of the proposed algorithm, including stability, accuracy, and overshoot behavior, are evaluated. The results show that the SSE-alpha algorithm offers flexible and controllable numerical damping, offering unconditional stability for both linear and softened nonlinear systems. This algorithm features second-order accuracy and can effectively reduce or eliminate overshoot through parameter adjustment. The comparative analysis with the G-alpha, WBZ-alpha, and MKR-alpha algorithms demonstrates that the proposed algorithm exhibits superior stability, precision, computational efficiency, and numerical damping characteristics. Finally, the effectiveness and stability of the SSE-alpha algorithm are confirmed through its application to different structural systems in RTHS. This algorithm ensures improved real-time computational accuracy and stability for the assessment of structural systems, including critical infrastructure under seismic loading, contributing to advancements in structural dynamics.