Design and manufacturing of filament wound elastomeric matrix composite flywheels

A procedure for the filament winding of thick glass and carbon fiber reinforced urethane matrix composite flywheels is presented. The impetus for fabrication of urethane matrix composite rings, which is discussed in the paper, stems from several potential advantages they may offer in high speed flywheels over conventional rigid epoxy matrix rings. The method developed uses continuous in-situ curing of the part while it is being wound to avoid compositional variations throughout the thickness, to eliminate fiber waviness and also to allow very high speed manufacturing. Urethanes typically have extremely high room-temperature viscosities and very short elevated temperature pot lives which combine to make conventional fiber impregnation schemes difficult. A method of diluting the resin with a solvent was developed in order to lower the viscosity. This method allows good room temperature fiber impregnation while avoiding the waste generated with continuous resin mixing systems for elevated temperature impregnation. After impregnation, heaters flash the solvent from the tow prior to being wound into the part. Results show that high quality parts with high fiber content (about 60%) and low void content (less than 1%) can be easily fabricated at radial deposition rates as high as 3.23 cm/hr (1.27 in/hr).