Dynamic modeling and earthquake response of a novel tuned lever negative stiffness damper for vibration control in NPPs

This study proposes a novel tuned lever–magnetically negative stiffness damper (TLNSD) for improving the seismic performance of structures, including both conventional buildings and nuclear power plant structures (NPPs). The TLNSD integrates a lever amplification device with a magnetically negative stiffness element to enhance the energy dissipation capacity of the system. The dynamic model of a single-degree-of-freedom (SDOF) structure with TLNSD is developed. Based on fixed-point theory and the H_∞ optimization criterion, analytical expressions for optimal damping and negative stiffness parameters are derived. Comparative analysis with the negative stiffness damper (NSD) and tuned inerter NSD (TINSD) shows that the TLNSD achieves superior vibration mitigation with lower damping and negative stiffness requirements. Additionally, it broadens the control frequency bandwidth and improves energy dissipation efficiency. Under both far-field and near-field pulse-like earthquakes, the TLNSD effectively reduces structural acceleration and displacement, with maximum reductions exceeding 60% in long-period conventional buildings. For multi-degree-of-freedom base-isolated NPPs, the TLNSD achieves up to 27% displacement reduction compared with the NSD. Lever amplification mechanisms and negative stiffness elements allow the TLNSD to significantly improve the energy dissipation capacity of its dampers. Although this study focuses on linear models, the TLNSD demonstrates strong potential as a compact, efficient, and cost-effective solution that enhances seismic protection across critical infrastructure.