Coupling vibration characteristics analysis and experiment,of shared support-rotors system

In view of the structural system of high power to weight ratio turboshaft engine with shared load bearing frame between turbine stages, the dynamic equation of the shared support-rotor system was established to explore the coupling vibration conditions and vibration characteristics of the gas generator rotor, the dynamic turbine rotor and the Shared load bearing frame structure system. Based on the ANSYS finite element simulation platform, the coupling vibration characteristics of the common bearing-rotor system were simulated by transient dynamics analysis method. For the inter-turbine load bearing frame of turbosshaft engine, a simulation tester of shared supplate-rotor system was designed, and a vibrator was used to simulate the unbalanced excitation of the rotor. The theoretical calculation results showed that the rotor fulcrum and the supporting structure were connected by force balance and displacement coordination, and there was a coupling stiffness between them, which led to the coupling vibration of the shared bearing-rotor system. The simulation results of the vibration response of the system under unbalanced excitation showed that the shared support could affect the dynamic characteristics of the rotor, and the vibration of the corresponding rotor could be excited by different unbalanced excitation of the rotor. It was verified through experiments that when coupled vibration occurred, the vibration response spectrum of the rotor contained two rotor speed frequencies at the same time, and the coupling influence coefficient was defined. The coupling influence coefficients between the two rotors in the idle state on the ground were 33% and 6079%, respectively. The maximum continuous state were 1278% and 688%, and the maximum take-off state were 1356% and 581%, respectively. The coupling influence of the dynamic characteristics between the rotors was related to the frequency.