Proposal of a new analytical model for hysteresis models using differential equation

Abstract

Many countries worldwide are advancing the development of next-generation reactors to improve safety. In Japan, rubber-bearing technology is being considered as part of earthquake countermeasures in these reactors. The force-displacement relationship of rubber bearings varies with compressive stress and shear strain, exhibiting strong nonlinear characteristics near ultimate behavior. Additionally, due to the recent increase in seismic activity levels, vertical seismic responses are considered significant when evaluating structural integrity. The authors have developed a hysteresis model that accounts for these characteristics in horizontal and vertical directions. Seismic response analysis beyond the design basis ground motion was conducted using this model, confirming the strong nonlinear relationships. Consequently, this model can accurately reproduce the force-displacement relationship in horizontal and vertical directions up to ultimate behavior. This paper presents the composition of the hysteresis model, considering these hysteresis characteristics.