A Theoretical Study on Piezoelectric Smart Isolation System for Seismic Protection of Equipment in Near-fault Areas

In order to enhance the efficiency and safety of seismic isolation for equipment subjected to near-fault earthquakes that usually possess a long-period pulse-like waveform, a semi-active isolation system named piezoelectric smart isolation system (PSIS), composed of a sliding isolation platform and a piezoelectric friction damper (PFD), is proposed in this study. By controlling the embedded piezoelectric actuator with a DC voltage, the friction force of the PFD can be regulated; therefore, the PFD is able to provide a supplemental damping, which is controllable by a predetermined control law, for the PSIS system. In order to evaluate its isolation performance, the seismic responses of the PSIS was simulated numerically, and the isolation performance of the PSIS was also compared with those of a passive and an active isolation system. The results of these comparisons are discussed in this study. The simulation result has shown that the PSIS can prevent both the excessive isolator displacement and equipment acceleration induced by the long-period pulse component of a near-fault earthquake.