Based on the circumferential distributed tie-rod rotor model with curvic couplings

the stiffness of every part of the rotor was acquired with analytical method. Three-dimensional finite element nonlinear contact method was adopted to analyse the flexural stiffness and torsional stiffness of the curvic couplings after preloading by using the commercial finite element software ANSYS. The stiffness correction coefficient and stiffness nondimensional coefficient were obtained. Coefficient of tie-rod stiffness ratio was adopted to describe the relation between the stiffness of tie-rods and disks. Results show that stiffness correction coefficient keeps steady when the stiffness nondimensional coefficient is less than 1

while it drops abruptly and the coefficient of tie-rod bend stiffness ratio increases when stiffness nondimensional coefficient exceeds 1. This means the preload is not enough and slip between curvic couplings happens. Stiffness nondimensional coefficient reflects some certain stress status of the curvic couplings

providing a basic guide for design and fault diagnosis of gas turbine rotor with curvic couplings.