Improved performance for hoop-wound composite flywheel rotors
Developmental work to date has shown the performance of hoop-wound composite flywheel rotors to be severely limited by composite transverse strength. This problem is addressed in a joint experimental-analytical effort aimed at improving transverse properties and assessing the impact of this improvement on flywheel performance. An improved test fixture designed to test hoop-wound cylinders in axial tension is developed. Test results show this specimen and test fixture produce more consistent data than do flat tensile bars cut from hexagonal cylinders. Initial experimental results from the improved specimen indicate that the transverse strength of Kevlar 49/epoxy composites could be improved by 30% by copolymerizing the epoxide matrix with an elastomer. The impact of these data on flywheel performance is predicted by a computer program which identifies optimum designs for given material properties on an energy-stored-per-swept-volume basis. A substantial improvement in performance is predicted, the attained 30% strength improvement of Kevlar 49/epoxy is shown to produce a 15% increase in energy stored. The analysis also permits multiple-material designs. Hybrid designs appear to have considerable potential for increasing storage capacity compared to single-material designs.
- Research Organization:
- Sandia Labs., Albuquerque, N.Mex. (USA); Nebraska Univ., Lincoln (USA). Dept. of Engineering Mechanics; Brunswick Corp., Lincoln, Nebr. (USA)
- DOE Contract Number:
- EY-76-C-04-0789
- OSTI ID:
- 5355705
- Report Number(s):
- SAND-77-1024C; CONF-771053-5
- Resource Relation:
- Conference: Flywheel technology symposium, San Francisco, CA, USA, 5 Oct 1977
- Country of Publication:
- United States
- Language:
- English
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