Development of Vibration Control Devices with an Origami Hydraulic Damper for Spherical Water Tanks

To improve the vibration reduction system applied to spherical water storage tanks under seismic conditions, a new origami-based hydraulic damper was proposed for use in tuned mass damper (TMD), replacing conventional cylinder-type hydraulic dampers. The configuration of the origami-based hydraulic damper, the vibration control mechanism of the TMD system using it, and tuning principle were examined. Shaking table experiments were conducted in the laboratory using a verification test apparatus that included an actual developed spherical water tank and a TMD system with an origami hydraulic damper. The tests were divided into cases based on different seismic waves and excitation directions. Shaking table experiments were conducted using actual earthquake waves from the Fukushima, El Centro NS, and Taft NW events. By comparing the measured response acceleration values, vibration reduction effects of 53.53%, 33.72%, and 36.63%, respectively, were obtained. Furthermore, to investigate the influence of the excitation direction on the vibration control performance, additional tests were conducted using the Fukushima earthquake wave with excitation angles varied in 15° increments. The tests demonstrated an average vibration reduction effect of 54.81% in terms of response acceleration. The results of these experimental measurements confirmed the stable vibration control performance of the proposed TMD system with an origami-based hydraulic damper applied to spherical water storage tanks.