Response prediction and optimization of a rotor with variable stiffness supports based on pseudo-steady approximation

The flexible rotor of an aero-engine must pass through several critical speeds within its working speed range, but its reliability can be compromised by intense vibration caused by the resonance at these critical speeds. A novel method for reducing multiple resonant peaks of a flexible rotor is explored based on multiple supports of variable stiffness in this paper. Firstly, to determine the optimal stiffness change path of these supports, a pseudo-steady approximation method (PSAM) considering the influence of support stiffness change rate is proposed for predicting time-domain responses based on frequency-domain calculations. This approach has a definite advantage in time-domain solutions as it is less time-consuming. Then, to verify the effectiveness of the PSAM, time-domain simulations are conducted, which yielded highly consistent results with the PSAM calculation results with the Structural Similarity Index (SSIM) up to 93.7%. Finally, with the assistance of the PSAM, the Dijkstra algorithm was used to identify the most efficient path of variable stiffness for controlling multiple resonant peaks of a flexible rotor. A rotor test was carried out utilizing variable stiffness supports which are made of shape memory alloy (SMA) springs. The efficiency of the optimal variable stiffness path acquired through PSAM was verified through testing, which demonstrated that displacement can be reduced by up to 70.8%.