The hysteresis model of the friction pendulum bearing based on the moment balance theory

The hysteresis model of the friction pendulum bearing (FPB) is very important for predicting its seismic performance. The previous hysteresis model is based on the horizontal force balance theory and cannot analyze the moment required when the FPB rotates. Because of this, this paper proposes a hysteresis model of the FPB based on the moment balance theory, which can be used to analyze the rotation performance of the FPB. In this paper, formulas of the hysteresis model of the FPB based on the moment balance theory are derived firstly. And it is found that the hysteresis loops calculated based on the moment balance theory is very close to those obtained from experiments. Then two main assumptions of the hysteresis model of the FPB based on the moment balance theory: Small rotation assumption and Normal stress assumption are introduced, and the expression of the hysteresis model of the FPB based on the moment balance theory without using the two assumptions is given. Finally, errors caused by the assumptions are analyzed in detail and the applicability of the simplified formula is verified.