High-performance vibration isolation technique using passive negative stiffness and semiactive damping

Among active, semiactive, and passive vibration isolation methods, active control can provide the best isolation performances. However, high-energy consumption hinders its wide applications in civil engineering field. This paper proposes a novel vibration isolation technique based on a passive negative stiffness spring (NSS) and a semiactive device (SAD), aiming to achieve an active isolation performance by using a low-power semiactive technique. Due to its nature of negative potential energy, an NSS enables the semiactive isolation system to provide negative transient power flow that injects power into the structure and avoids the clipping phenomenon of semiactive control forces. Consequently, the combined NSS and SAD isolation system can perfectly generate the theoretical control forces calculated by an active control algorithm and achieve a considerably improved semiactive isolation performance. The prospects and performance advantages of the proposed NSS and SAD isolation system are validated through a series of numerical simulations of single-degree-of-freedom and multi-degree-of-freedom structures excited by various types of ground motions and a benchmark building model excited by seismic ground motions.