STUDY ON VERTICAL RESTORING FORCE DEVICE USING DISC SPRINGS

Abstract

Examination of Optimum Combination of Disc Spring Units and Identification Method of Hysteresis Loop The authors developed a three-dimensional seismic isolation system to ensure isolation performance in the vertical and horizontal directions. This isolation system is required for a large-scale disc spring to achieve both the support and isolation functions. Additionally, two methods are required: one is to control the variance of restoring force, and the other is to predict the isolation performance using a response analysis. This paper describes an optimal combination method of disc springs to absorb the variance caused by the manufacturing process by calibrating the combination using a metaheuristic algorithm. Moreover, a method to identify the variables of the hysteresis loops caused by the combined disc springs is proposed using the metaheuristic algorithm. The applicability of these methods is verified using the static loading tests data obtained by a large-scale disc spring that expands the dimensions defined by the JIS B 2706:2013 and the ISO 19690-1:2017. The static loading tests were conducted using 72 disc springs with 350 mm in diameter and six − disc springs with 700 mm in diameter. This paper demonstrates that the proposed method can control the restoring force and identify the variables required for hysteresis loops accurately and efficiently.