Internal-flow Origami Hydraulic Damper with Nonlinear Damping Characteristics

In a wide range of industrial fields, the advancement of hydraulic dampers for vibration control has become an important research and development topic. In this paper, we propose a novel internal-flow origami hydraulic damper with nonlinear damping characteristics to overcome the limitations of conventional cylindrical hydraulic dampers with restricted linear strokes. First, the basic structure and design method of the proposed origami hydraulic damper are examined. Subsequently, the flow characteristics of the internal fluid in the origami hydraulic damper are analyzed, and a formula is derived to calculate the damping force acting on the damper. We confirm that the damping force is proportional to the square of the velocity. Furthermore, a verification experimental system using a nonlinear origami hydraulic damper in a mass-spring vibration system was developed. Shaking experiments using actual Fukushima earthquake waves were conducted, and the response acceleration decreased by 63.49%. For further verification, shaking experiments were performed by changing the orifice diameter of the nonlinear origami hydraulic damper, and the average reduction rate of the response acceleration for different orifice diameters was 62.68%. In addition, to verify the vibration control effect under different earthquake waves, we conducted shaking experiments using the same experimental setup and conditions as those used for the El Centro NS and Taft NW earthquake waves. The average reduction rate of the response acceleration for different earthquake waves was 62.22%. Thus, the damping characteristics and effectiveness of the proposed internal-flow origami hydraulic damper were confirmed.