Experimental verification of a piezoelectric smart isolation system

To improve the performance of conventional seismic isolation technology, a semi-active isolation system, named a 'Piezoelectric Smart Isolation System (PSIS)', which is composed of a sliding isolation platform and a piezoelectric friction damper (PFD), is introduced and investigated experimentally in this study. Because the friction force of the PFD in the PSIS can be regulated by an embedded piezoelectric actuator through a DC voltage, the PFD is able to provide a controllable damping force for the isolation system. As a result, the seismic response of the PSIS can be effectively controlled and mitigated. In order to verify its feasibility, a prototype PSIS was fabricated and tested dynamically via a shaking table test. The accuracy of the test data has been confirmed by the good consistency between the experimental and theoretical results. The experimental results have demonstrated that, when compared to the uncontrolled counterpart, the PSIS is able to substantially suppress both the displacement and acceleration responses in an earthquake with either near-fault or far-field characteristics. The study has also shown that, although the semi-active PSIS system can only provide a variable passive control force, it is able to achieve the same level of control performance as an actively controlled isolation system, which shares the same optimal feedback gain as that of the PSIS.