Fabrication and Spin Tests of Thick Laminated S2-Glass Flywheel Disks

Flywheels have been used to store and supply energy in a wide range of applications. In transportation-related applications, a primary design consideration is to store the maximum amount of energy per unit weight of the flywheel. Based upon this criterion, the high strength-to-density ratios of composite materials make them attractive materials for an efficient design. This investigation reports on a program to develop a composite flywheel consisting of a laminated S2-glass/epoxy central disk and a filament-wound graphite/epoxy outer ring. It is shown both analytically and experimentally that the presence of the outer ring significantly improves the energy density available in a simple laminated disk. Consideration is given to the subjects of fabrication, failure criteria, and experimental determination of ultimate speed and strength of prototype flywheels.