Abstract: A flywheel formed of a composite material having fibers, oriented substantially in a circumferential direction around the flywheel, embedded in a matrix material. The flywheel having an inner surface, an outer surface, and a thickness therebetween and defining an axis of rotation. A plurality of load masses are distributed circumferentially on the inner surface at a longitudinal segment along the axis. A rotation of the flywheel about the axis with a rotational velocity generating hoop stress in the fibers in the circumferential direction and through-thickness stress is generated in the matrix material in a radial direction. Each load mass produces a force on the inner surface operative to reduce the maximum through-thickness stress in the matrix material as the flywheel rotates about the axis. The rotational velocity otherwise sufficient to produce structural failure of the matrix material produces structural failure of the fibers and not the matrix material.

Abstract: A flywheel formed of a composite material having fibers, oriented substantially in a circumferential direction around the flywheel, embedded in a matrix material. The flywheel having an inner surface, an outer surface, and a thickness therebetween and defining an axis of rotation. A plurality of load masses are distributed circumferentially on the inner surface at a longitudinal segment along the axis. A rotation of the flywheel about the axis with a rotational velocity generating hoop stress in the fibers in the circumferential direction and through-thickness stress is generated in the matrix material in a radial direction. Each load mass produces a force on the inner surface operative to reduce the maximum through-thickness stress in the matrix material as the flywheel rotates about the axis. The rotational velocity otherwise sufficient to produce structural failure of the matrix material produces structural failure of the fibers and not the matrix material.

Abstract: A flywheel formed of a composite material having fibers, oriented substantially in a circumferential direction around the flywheel, embedded in a matrix material. The flywheel having an inner surface, an outer surface, and a thickness therebetween and defining an axis of rotation. A plurality of load masses are distributed circumferentially on the inner surface at a longitudinal segment along the axis. A rotation of the flywheel about the axis with a rotational velocity generating hoop stress in the fibers in the circumferential direction and through-thickness stress is generated in the matrix material in a radial direction. Each load mass produces a force on the inner surface operative to reduce the maximum through-thickness stress in the matrix material as the flywheel rotates about the axis. The rotational velocity otherwise sufficient to produce structural failure of the matrix material produces structural failure of the fibers and not the matrix material.

Abstract: A flywheel formed of a composite material having fibers, oriented substantially in a circumferential direction around the flywheel, embedded in a matrix material. The flywheel having an inner surface, an outer surface, and a thickness therebetween and defining an axis of rotation. A plurality of load masses are distributed circumferentially on the inner surface at a longitudinal segment along the axis. A rotation of the flywheel about the axis with a rotational velocity generating hoop stress in the fibers in the circumferential direction and through-thickness stress is generated in the matrix material in a radial direction. Each load mass produces a force on the inner surface operative to reduce the maximum through-thickness stress in the matrix material as the flywheel rotates about the axis. The rotational velocity otherwise sufficient to produce structural failure of the matrix material produces structural failure of the fibers and not the matrix material.

Abstract: A flywheel formed of a composite material having fibers, oriented substantially in a circumferential direction around the flywheel, embedded in a matrix material. The flywheel having an inner surface, an outer surface, and a thickness therebetween and defining an axis of rotation. A plurality of load masses are distributed circumferentially on the inner surface at a longitudinal segment along the axis. A rotation of the flywheel about the axis with a rotational velocity generating hoop stress in the fibers in the circumferential direction and through-thickness stress is generated in the matrix material in a radial direction. Each load mass produces a force on the inner surface operative to reduce the maximum through-thickness stress in the matrix material as the flywheel rotates about the axis. The rotational velocity otherwise sufficient to produce structural failure of the matrix material produces structural failure of the fibers and not the matrix material.

Abstract: This invention provides for a method to provide the highest possible stored energy density (Watt-hour/kg) in rotating composite flywheels, which in turn will enable an increased application of said devices. Segmented high density (mass loading) materials are positioned and bonded against all free inner surfaces of a high strength low density composite rotor/rim. Traditional composite flywheels do not incorporate mass loading of the composite rotor, i.e., most of the stored energy is contained in the rotating composite rotor. The segmented materials do not fail under the high centrifugal loads, thereby contributing significantly to the overall stored energy density of the composite flywheel system. The high strength composite rotor is engineered to withstand the additional centrifugal loading effects imparted from the segmented masses. An additional benefit from completely loading the inner surface of the composite rotor as uniformly as possible is that it minimizes any unwanted rotor dynamic instabilities.

Abstract: In one embodiment, an apparatus, includes: a mandrel; an expansion cylinder, comprising: opposite first and second ends; an inner circumferential surface extending between the ends and characterized by an inner diameter, the inner circumferential surface defining a hollow cavity; an outer circumferential surface extending between the ends and characterized by an outer diameter that is greater than the inner diameter; and a plurality of slots extending from the inner circumferential surface to the outer circumferential surface and latitudinally oriented between the ends; and one or more base plates configured to engage one of the ends of the expansion cylinder. In another embodiment, a method includes: arranging an expansion cylinder inside a test cylinder; arranging a mandrel inside the expansion cylinder; applying a force to the mandrel for exerting a radial force on the expansion cylinder; and detecting one or more indicia of structural failure of the test cylinder.

Abstract: In one embodiment, an apparatus, includes: a mandrel; an expansion cylinder, comprising: opposite first and second ends; an inner circumferential surface extending between the ends and characterized by an inner diameter, the inner circumferential surface defining a hollow cavity; an outer circumferential surface extending between the ends and characterized by an outer diameter that is greater than the inner diameter; and a plurality of slots extending from the inner circumferential surface to the outer circumferential surface and latitudinally oriented between the ends; and one or more base plates configured to engage one of the ends of the expansion cylinder. In another embodiment, a method includes: arranging an expansion cylinder inside a test cylinder; arranging a mandrel inside the expansion cylinder; applying a force to the mandrel for exerting a radial force on the expansion cylinder; and detecting one or more indicia of structural failure of the test cylinder.