The Structure Design For The Rim Of The 10kWh Flywheel Rotor On Composite Materials

As a new efficient energy technology, the flywheel energy storage has a broad range of applications. The composite flywheel rotor is an important component in the flywheel energy storage system(FESS), completing the energy storage and release at work. The capacity of storing energy in the FESS is closely related to the structure of the composite flywheel rotor,so designing the structure of the composite flywheel rotor is of great significance to improve the specific energy density.According to the design requirements for the lOkWh composite flywheel energy storage system, with the rim of the composite flywheel rotor as studying object, this paper was concerned with influences of some factors, such as rings, interference values, thickness and tapers, on the Von Mises equivalent stress distribution of the metal hub and the radial stress distribution of the composite materials rim by using the finite element method. And the composite materials rim was fabricated based on the analysis results.The results showed that the rings affected the stressed state of the rim. When the rim was made by one ring, only a small part of fibrous layers of the rim came under the compressive stress. Almost the entire rim came under the compressive stress with the number of the rings increasing to three. So we can conclude that the compressive stress area of the rim becomes larger as the number of the rings is increasing; Changing the interference values had an effect on the compressive stress area. For the two ring composite flywheel rotor, the compressive stress area of the rim became larger when the internal interference values increased from 0.2mm to 0.4mm and the external interference values increased from 0.3mm to 0.5mm. So we can conclude that higher interference values mean greater compressive sltress area; The thickness of each ring influenced the radial stress distribution of the composite materials.When the thickness from inner ring to outer ring was becoming smaller, the mechanical property of the three ring composite flywheel rotor was the worst., it could not meet the job requirements because the thickness of the inner ring was too large. When the thickness of each ring was equal, almost the entire rim came under the compressive stress. Compared with the equivalent thickness composite rim,the three ring composite flywheel rotor came under a larger tensile stress area when the thickness from inner ring to outer ring was becoming larger;The change of tapers did not affect the radial stress distribution of the composite materials rim as much; Changing the structure of the composite materials rim had no significant effects on the Von Mises equivalent stress distribution of the metal hub.Based on the analysis results, together with machining and assembly technology, the structure of the composite materials rim was determined: the rim was made by three rings; the interference values between each ring was 0.2mm, 0.2mm, 0.3mm from inner to outer; the thickness of each ring was equal; the direction of each ring's taper was identical and the dimension was the same as the metal hub.