Spin test of three-dimensional composite rotor for flywheel energy storage system

A rotating disk often undergoes severe vibration at high rotation speeds because of unstable joining between the disk and a drive shaft. As described herein, three connection methods between a driving shaft and an annular rotation disk made of three-dimensionally carbon-fiber reinforced composite were discussed to achieve stable rotation at high rotation speeds by changing the hub material and joining geometry: the connecting device. In two of the three methods, the vibration amplitude increased at a tip speed higher than 500 m/s. Key factors that caused the vibration were analyzed. Results show that the third method by which a resin ring (hub) was inserted between the disk and rotation shaft maintained stable joining, even at high-speed rotation.