A Stiffness Method Using Slice Coupling for Curvic Couplings Connection Structure Of Rod-Fastening Combined Rotor with Fretting Wear

Abstract Modern heavy-duty gas turbines primarily adopt a rod-fastening combined rotor, in the turbine of the combined rotor, the curvic couplings connection structure is commonly used to transmit force and torque. Based on the slice discretization, a time-varying connection stiffness calculation method is proposed by considering the fretting wear on the curvic couplings. The fretting wear simulation of the curvic couplings connection structure was conducted based on the modified Archard?s wear theory and finite element method. Subsequently, the effects of load conditions on connection stiffness during the progress of fretting wear are investigated. The simulation results show that worn connection stiffness is generally lower than the initial connection stiffness. The decreased preload and increased transmitted torque will decrease the initial connection stiffness, and exaggerate the wear on the annular flat, which leads to a decline in worn connection stiffness. The gap between the connection stiffness before and after wear will exaggerate with the increase of the rotational speed. Ultimately, this research will provide a reference for the structural design of the annular flat connection structure and a new idea for researchers to further study.