Finite Element Analysis of a Shrink Fitted Disc-Shaft Rotating System

In this paper, the shrink fit between the conical disk and the rotor shaft of a steam turbine was analysed with the aim of determining the rotor speed at which this fit is lost. The analysis was carried out numerically using the finite element method (FEM) in the Ansys software package. Three design values of disc-shaft joint interference were considered: minimum, maximum and mean. The rotor speed at which the shrink fit is lost is the lowest for minimum interference and the highest for maximum interference, which was expected. In other words, the rotor speed at which the shrink fit is lost is a linear function of the amount of interference (the allowance). The results of the analysis showed that the considered interferences of the shrink fit ensured the smooth transmission of torque in the range of speeds up to the operating speed and that the operation of the turbine is safe from that point of view.