RESEARCH ON MECHANICAL PROPERTIES AND ISOLATION EFFECT OF A ISOLATION BEARING WITH MULTI-STAGE FREQUENCY-CONVERSION COMPOSITE FRICTION PENDULUMS

In order to avoid the resonance damage of the friction pendulum isolation structure and the upper structure, a multi-stage frequency conversion friction pendulum isolation bearing with a variable curvature and friction coefficient arc sliding surface was developed. The mechanical properties and isolation mechanism were expounded. The theoretical analysis of the dynamic equilibrium equation showed that the natural vibration period of the multi-stage frequency conversion friction pendulum isolation bearing was only related to the friction coefficient μ of the frictional pendulum, the radius of the arc surface R and the horizontal displacement of the friction pendulum. The solid model was made, and the mechanical properties such as the restoring force model and friction coefficient were tested by experiments. The ABAQUS finite element software was used to simulate a 6-story frame structure set up by this isolation bearings. The dynamic responses of the structure under earthquake action before and after installing isolator were compared. The research showed that the multi-stage frequency conversion friction pendulum had good stability, frequency conversion capability, self-limiting and self-restoring capacity, and was suitable for multi-stage isolation scheme, which did not need to be equipped with a separate damper. The multi-stage frequency conversion friction pendulum showed the advantages of simple structure, convenient application and good isolation effect.