A Test Plan for Fatigue and Residual Strength of Composite Flywheel Rotors

A test plan for fatigue and residual strength for composite flywheel rotors can be rationally devised using master curves derived from time-temperature superposition principle. Validity of this plan will be demonstrated in Phase I using our theory and limited number of spin tests. Instead of S-N curves, this methodology forms a generic durability prediction methodology. Effects of frequency, stress ratio, combined hoop, radial and shear stresses, and high temperature can all be treated in one rational framework. Dozens of small-size calibration rotors and limited number of full-size ones will be in the Phase II test plan to generate fatigue master curves. Honeywell will provide operational characteristics and requirements so realistic thermal and mechanical loads can be imposed. Fatigue life and residual strength of rotors subjected to repeated, rapid discharges and arbitrary temperature history can be systematically determined with no need for curve fitting. All these simulation capabilities will be incorporated in Super Mic-Mac/Rotor, a friendly rotor design tool for engineers. Eventual testing of Think Composites rotor in Honeywell system as part of Phase II is envisioned.