Seismic Performance Assessment of Quintuple Friction Pendulum Isolator with a Focus on Frictional Behavior Impressionability from Velocity and Temperature

摘要

This paper describes the development of a numerical model using finite element modeling (FEM) with the ability to simulate and analyze the thermal-mechanical behavior of a new generation of curved surface sliders called as Quintuple Friction Pendulum Isolators (QFPIs). The QFPI is a spherical sliding isolator with six sliding surfaces, five effective pendula, and nine stages of operation which allow for a multistage adaptive behavior depending on the amplitude of displacement. The focus of this study is on the effect of velocity, heat generation, and temperature rise, which occurs at the sliding surfaces under large friction forces and high velocities, on the frictional behavior of this new type of isolators. Heat generation is simulated through a heat source located on the sliding surfaces, with surface heat flux intensity dependent on the coefficient of friction, the contact pressure, and the velocity. At the same time of the mechanical analysis, the thermal calculation was also done and the coefficient of friction is adjusted step by step on the current temperature and velocity at the sliding surfaces. To validate the numerical approach, the hysteretic force-displacement behavior of isolator is compared by that of the experimental test result. Moreover, seismic performance of this type of new sliding isolators was analyzed and evaluated in terms of the effective stiffness, K (eff), and the energy dissipated per cycle, EDC or E (loop), based on EN 15129, ASCE 7-10, ASCE 7-16, and AASHTO 2014 codes. The assessment results show that the codes requirements on the maximum allowable variation in K (eff) and EDC are fulfilled. The numerical process can help in early studies to select the isolator materials accounting for their thermal consistency and evaluating the design properties variation of sliding isolation due to frictional heating.