RESEARCH AND DEVELOPMENT OF VISCOUS FLUID DAMPERS FOR IMPROVEMENT OF SEISMIC RESISTANCE OF THERMAL POWER PLANTS PART 6 INFLUENCE OF DAMPER PROPERTIES ON VIBRATION CONTROL PERFORMANCE

摘要

Coal-fired thermal power generation became a very important power source in Japan after Great East Japan Earthquake [1]. Therefore improvement of seismic reliability of the coal-fired thermal power plants is required, because occurrence of very large earthquakes is expected in Japan. Boilers of coal-fired power plants are usually suspended from the upper end of support structures in order to allow thermal expansion of the boilers [2], so boilers easily sway during 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 are effective for vibration suppression, further countermeasure for earthquakes having long duration and many aftershocks is required. Authors have developed a vibration control damper for coal-fired power plants. The damper is set instead of conventional stopper. Construction of the damper is similar to oil dampers, but inner fluid is viscous fluid. In PVP2017, the basic performance of the proposed damper was presented [3-5]. In this paper, damper properties were adjusted in order to improve vibration control performance of the damper. Influence of damper properties on the performance was investigated by sensitivity analyses. In addition, influence of dispersion of damper properties was also investigated. Long period and long duration earthquake waves were considered in the analyses.