Lateral-torsional coupled vibration analysis of a dual-rotor system with bolted joint structure considering stick-slip behavior at mating interface

Interface stick-slip behavior will be induced for the assembly system during the long-term and complex vibration environment, further inducing strong nonlinear stiffness and damping. For this reason, the present work established a dynamic model of the bolted joint dual-rotor system considering interface stick-slip behavior and conducted a parametric analysis of the effect of the preload and speed ratios on the system’s lateral-torsional coupled vibration performance. Wherein the interface stick-slip behavior is simulated by adopting the Iwan model, and the equations of motions of the dual-rotor system, including the low-pressure (LP) and high-pressure (HP) rotors, are established based on the lumped mass method. The results indicate that both the preload and speed ratio have a significant effect on the variation of equivalent average stiffness of the bolted joint induced by the interface stick-slip behavior and then affect the amplitude-frequency characteristics of the rotor system. Moreover, the torsional vibration of the HP rotor system is more sensitive to the interface stick-slip state, and the continuous frequency spectra and high-order harmonic frequency in the lateral and torsional frequency spectrum of the HP rotor can be used to estimate the interface stick-slip state. Finally, the experimental study is carried out based on a bolted joint dual-rotor test rig to verify some key findings from numerical simulation. The research results can provide valuable insights into the dynamic properties prediction and health monitoring of a bolted joint dual-rotor system.