The squeeze film damper (SFD) is a damping device that has been widely used in rotating machines. The SFD can effectively suppress rotor vibration and reduce transmitted forces. However, it would cause complex motions of the rotor system under specific operating conditions. This paper investigates the support structure of a high-pressure stage simulated rotor in an aircraft engine. A dynamic model of the SFD considering the effects of inertia and cavitation is established to investigate the influence of structural parameters on the stiffness and damping coefficient of the damper. Subsequently, a finite element model of the Jeffcott rotor–SFD system is developed to explore the effects of the structure parameters of the SFD on the critical speed, mode shapes, and other dynamic characteristics of the Jeffcott rotor–SFD system. Experimental tests are conducted to validate and refine the numerical calculations regarding the dynamic characteristics of the rotor–damper system. The results indicate that there is consistency between numerical simulations and experimental results. Within a certain range, enlarging the width of the damper can significantly increase the magnitude of the pressure distribution of the oil film. However, when the pressure amplitude increases to the saturation vapor pressure of the lubricating oil, the cavitation effect begins to manifest. As the width of the damper increases, both the stiffness coefficient and damping coefficient of the SFD are enhanced. Consequently, the vibration reduction effectiveness of the SFD is significantly improved.

The rotor is a crucial component in rotating machinery, where its stability directly impacts performance and safety. Imbalance-induced vibrations can cause severe component wear, resonance instability, and even catastrophic failures, especially in high-speed systems like aero-engines. While the squeeze film damper (SFD) is widely used for vibration suppression, the effects of imbalance (manifested as SFD eccentricity) on its dynamic performance are not well understood. Additionally, the combined impact of imbalance and acceleration on rotor–SFD system stability has not been systematically investigated. This study uses numerical simulations to explore the influence of SFD eccentricity, caused by imbalance, on its dynamic characteristics. Experimental tests are conducted to examine the effects of imbalance and acceleration on rotor–SFD dynamics. Results show that increasing imbalance raises SFD eccentricity, reducing the effective oil film bearing area. This results in a rapid increase in the oil film’s stiffness and slower growth in damping, enhancing nonlinearity and reducing stability. Under small imbalance conditions, increasing acceleration improves stability by facilitating critical speed crossing and reducing vibration amplitude. However, excessive imbalance renders acceleration control ineffective, exacerbating system instability. This study provides valuable insights into the interaction between imbalance, acceleration, and SFD performance, offering guidance for optimizing rotor–SFD system parameters and ensuring stable operation.

Rotating machinery is a crucial component in modern industrial systems, offering high efficiency and reliable performance. However, vibration issues significantly shorten their operational lifespan. Squeeze film dampers (SFDs), due to their simple structure, low cost, and effective vibration reduction, are widely used in these systems. However, the strong nonlinearity of SFDs means existing designs often rely on trial-and-error methods. This study focuses on optimizing damper parameters, particularly the clearance ratio, which is a key design factor. A numerical model based on kinetic equations and elastic supporting vibration theory is developed to explore the relationship between damper transmissibility and speed coefficient across different clearance ratios. The impact of clearance ratio on squeeze film dynamics is further examined through experimental tests on a rotor-SFD system. Results show that at a clearance ratio of 0.3%, a stable squeeze film forms, minimizing two-phase flow effects and maximizing film carrying capacity. This research provides valuable insights into enhancing the efficiency of damper designs in rotating machinery.

Squeeze film damper (SFD) is damping devices which has been widely used in rotating machines. SFD can effectively suppress rotor vibration and reduce transmitted forces.The dynamic characteristic model of the SFD considering inertia force was established, and the finite element model of the...