Characteristic and Modeling of Multiple Direction Optimized-Friction Pendulum System With Numerous Sliding Interfaces Subjected to Multi-Directional Excitations

In this paper, a base isolator call the multiple direction optimized-friction pendulum system (Multiple DO-FPS) with numerous sliding interfaces is proposed. For understanding the mechanical behavior of the Multiple DO-PFS isolator under multi-directional excitations, an analytical model called the multiple yield and bounding surfaces model is also proposed. On the basis of the derived mathematical formulations for the simulation of the characteristic of the Multiple DO-FPS isolation bearing, it is revealed that the natural period and damping effect for a Multiple DO-FPS is a function of the sliding displacement and sliding direction. By virtue of the proposed model, the phenomena of the sliding motions of the Multiple DO-FPS isolator with numerous sliding interfaces subjected to multi-directional excitations can be simply understood. Analytical results infer that the natural frequency and damping effect of the Multiple DO-PFS isolator with numerous concave sliding interfaces change continually during earthquakes and are controllable through appropriate designs.