Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 8 — Evaluation of Vibration Control Performance Using Experimental Design Method

Abstract

After Great East Japan Earthquake, coal-fired thermal power generation is a very important power source in Japan. In addition, Hokkaido Eastern Iburi Earthquake occurred in Japan in 2018, and damage of coal-fired thermal power plants by this earthquake caused blackout in very wide area. Therefore improvement of the seismic performance of the thermal power plants is a very important issue. In general boilers of coal-fired power plants are suspended from the upper end of support structures in order to allow thermal expansion of the boilers. Therefore boilers are structures that easily sway by earthquakes. In order to suppress the vibration, stoppers made of steel are generally installed between boilers and their support structures. Although stoppers made of steel can suppress the vibration effectively and economically, further improvement of seismic performance is required from the viewpoint of abovementioned issue. Therefore authors have proposed and developed a vibration control damper for coal-fired power plants instead of the stopper made of steel. Construction of the damper is similar to oil dampers, but inner fluid is viscous fluid. In PVP 2017, the basic performance of the proposed damper was presented. In PVP 2018, influence of dispersion of damper properties was also investigated. In addition, seismic response analyses using various earthquakes that include long period and long duration earthquake waves were carried out. As a result of previous investigations, it was confirmed that the proposed damper has good performance in its lifetime. However, parameters of dampers were selected manually. Therefore, influence of parameters of dampers on the vibration control performance were evaluated theoretically by using the experimental design method in this paper. The experimental design method is one of the effective techniques for research such as investigation of the influence of the habitat environment on the growth of crops. The selection of damper parameters is complex optimization, because so many variables need to be optimized. Therefore the experimental design method is suitable technique for the evaluation of damper parameters. This paper will evaluate vibration control performance from the viewpoint of the experimental design method.