Evaluation and design considerations of woven composite flywheel materials constructions
Work performed from November 1979 to June 1981 on projects for evaluating the specific energy density capability of bidirectional woven flywheel materials and for developing design approaches for the optimization of those materials is reported. After demonstrating the basic geometry needed to construct a constant stress composite flywheel, a method of construction that can integrate radial and hoop fibers, control the relative stiffness in these two principal directions, and offer low cost in production is explained. Such a construction can be accomplished by weaving the radial fibers with the hoop fibers to form a cloth with a circular or spiral configuration. In this design, the warp fibers become the hoops and the pick fibers become the radials. The varying of radial stiffness is controlled by the choice of the pick pattern. In order to evaluate the circular weave, 0.2-in.-thick discs of approximately 20 in.-dia. were molded using S-glass weave and an epoxy matrix. Tensile specimens cut from the discs in both the radial and hoop directions were tested to failure. Further analyses and tests were performed to determine the optimum weave arrangement and the percent of fiber volume needed to optimize the specific material strength. These analyses show that there is a relatively wide range of pick to warp ratios which achieve optimum specific energy densities and that this range includes ratios that are relatively simple to fabricate. The tensile test data show that specific strengths of the fiberglass circular weave approximate 2.5 x 10/sup 6/ in. which results in energy densities at burst of 35 to 40 W-h/lb. A percent of active composite encompassed by the OD for the composite of 78% has been demonstrated. Fiberglass data suggest that the circular weave flywheel can operate over a life cycle equivalent to 10/sup 6/ deep cycles at the energy density level of 15 W-h/lb. (LCL)
- Research Organization:
- Lawrence Livermore National Lab., CA (USA); Avco Systems Div., Wilmington, MA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5273215
- Report Number(s):
- UCRL-15415; ON: DE82006781
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
COMPOSITE MATERIALS
TENSILE PROPERTIES
FLYWHEELS
ENERGY DENSITY
FABRICATION
EPOXIDES
EXPERIMENTAL DATA
FIBERGLASS
MATERIALS TESTING
DATA
INFORMATION
MATERIALS
MECHANICAL ENERGY STORAGE EQUIPMENT
MECHANICAL PROPERTIES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
TESTING
250500* - Energy Storage- Flywheels
360600 - Other Materials