Stress distribution and contact status analysis of a bolted rotor with curvic couplings

Abstract

The aim of this article is to provide some basis for the design and assembly of a bolted rotor with curvic couplings. It is well known that the key difference between a bolted rotor with curvic couplings and an integrated one is the contact interface. According to the characteristics of curvic couplings and spindle bolts, the model of a bolted rotor with curvic couplings of the turbine end of a heavy duty gas turbine was built. A method of accurately applying the preload force has been studied in this article. The three-dimensional finite-element contact method was used, non-linear behaviours such as friction and contact were also taken into account, and the dynamic contact between the spindle bolts and the sidewall of turbine wheels was included. The tendency of stress, which involved the rotor, curvic couplings, and the spindle bolts, was determined and the radial slippage trend of curvic teeth was also determined, by investigating the stress distribution and contact behaviour of the bolted rotor with curvic couplings during the course of preload, warm-up, speed-up, and running. It can be seen from the results that the contact stress of curvic couplings is dominant during the course of preload, and the bent stress is dominant when the rotating speed increased to 3000 r/min; the stress inequality on two sides of a tooth is caused by torque, so the stress proportion induced by torque should be restricted to an appropriate level to avoid anisotropy of the rotor.