Experimental and analytical investigation of variable friction pendulum isolator

This study develops a variable friction bearing (VFPB) that introduces a variable friction mechanism into a traditional friction pendulum bearing (FPB), in which a new friction composite is applied. The device is developed using simple processing technology. A method for determining which sliding band is active based on the friction coefficient of each sliding band is proposed, and the operating principle of the VFPB is illustrated. The force-displacement relationships and relevant parameters of interest are subsequently derived based on the principles of operation of the VFPB. Parametric studies are conducted to investigate the effects of the friction coefficient and number of sliding bands on the behavior of this novel VFPB. To investigate the mechanical behavior of the VFPB under various vertical loads and sliding velocities, characterization tests for a full-scale VFPB are carried out. An analysis model consisting of existing nonlinear elements is proposed for time-history analysis because it can be immediately implemented in currently available analysis software. The error of the analysis model is controlled within 10%.