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In low earth orbit satellite applications, spacecraft power is provided by photovoltaic cells and batteries. Unfortunately, use of batteries present difficulties due to their poor energy density, limited cycle lifetimes, reliability problems, and the difficulty in measuring the state of charge. Flywheel energy storage offers a viable alternative to overcome some of the limitations presented by batteries. FARE, Inc. has built a 50 Wh flywheel energy storage system. This system, called the Open Core Flywheel, is intended to be a prototype energy storage device for low earth orbit satellite applications. To date, the Open Core Flywheel has achieved a rotational speed of 26 krpm under digital control.

Often an accident reconstructionist is asked to determine vehicle speeds where the vehicle impacts a roadside object. One class of roadside objects that can be involved in the impact are the end treatment energy absorbing systems of “Jersey” barriers, guard rails and bridges. One such end treatment system is known as the Guard Rail Energy Absorbing Terminal, G-R-E-A-T. The G-R-E-A-T system consists of 6 to 8 foam and metal honeycomb cartridges surrounded by a framework of triple-corrugated steel guardrail. The number of cartridges used determine the maximum impact speed the barrier will safely handle. This type of accident cannot be analyzed as a fixed barrier impact. A method has been developed to determine the impact speed of a vehicle that has hit a constant force ( constant deceleration ) energy absorbing end treatment system.

This paper outlines a manufacturing analysis of a composite flywheel that can then be manufactured, assembled, balanced, and integrated with a magnetically suspended system test apparatus, for use in an inertial energy storage system. The preferred flywheel geometry was found to be a constant thickness disk with a hole in the center, having an inside to outside diameter ratio of 0.45. On the basis of the detailed stress analysis performed, the usable stored energy density of the interference assembled flywheel is 65 Watt - hour/kg, when operating over a speed range of 37.5% to 75% of maximum speed. The preferred flywheel fabrication method is wet filament winding, with high strength carbon fibers, in an epoxy matrix. These fibers are arranged in the hoop direction. A composite material test program was designed to validate the required performance of the, composite material.

AMBER (Active Magnetic Bearing Evaluation Routine) is a computer algorithm developed for the University of Maryland pancake magnetic bearing, which supports and controls a flywheel in a kinetic energy storage system. Because of the gap growth due to centrifugal forces at high speed, the bearing axial load capability degrades and the axial characteristics become critical in the bearing design. AMBER applies magnetic circuit theory, magnetic material saturation curves, coenergy theory, and finite permeance-based elements to solve the air gap flux density and coenergy over a series of incremental axial displacements. Differentiation of the coenergy of the magnetic field yields axial force and stiffness characteristics. An axial test machine is constructed to conduct experiments to verify the flux distribution and axial forces predicted by the model. User interaction with AMBER allows modification of the bearing geometry and composition to optimize future prototypes.