Abstract: The flywheels on reactor coolant pump motors provide inertia to ensure a slow decrease in coolant flow to prevent reactor damage as a result of a loss of power to the pump motors. Interference fits serve to control critical speeds of the rotors. During overspeed, the flywheel enlarges and gravitates from the vertical shaft to prevent itself from a loss of integrity. A safe flywheel assembly is developed which separates ring by ring at critical speeds. Plane stress method and FE model with gap elements are used to design the interference and evaluate the stress distribution. The whole frictional contact process: sticking, sliding, and gravitating under the influence of rising centrifugal forces is simulated.

Key words: FEM, Flywheel, Gap element, Initial interference, Nonlinear contact, Cutter deflection, Cutting edge, Dies finish machining, Hardened steel, Limit cutting depth