Structural design and optimization of metallic flywheel based on FEM

Adopting metallic flywheels is an important way to promote the applications of flywheel energy storage for its superiorities in power density and reliability. This study is aimed to design and optimize metallic flywheel with FEM, considering stress intensity, metal fatigue, energy storage capacity, energy density and processing technology comprehensively. The designed energy capacity was beyond 20 kW·h using the alloy 35CrMoA. Frequent charge-discharged flywheels use 4 times the safe coefficient to realize high reliability, while high-speed standby flywheels took Fatigue ultimate strength as the criterion to balance the energy capacity and lift-time. By contrast, the dumbbell-shaped cross-section was conducive to a larger moment of inertia with a lighter weight, benefitting for reducing the bearing load. Besides, this paper proposed a novel design of lamina-riveted flywheel, and accessed the influence of the axle hole and screw holes. All the above discussion provided available references for the further design and mass production of low-speed/high-power metallic flywheels.