Vibration Reduction in Rotating Systems Using Squeeze Film Dampers and Magnetic Bearings

Abstract

This study investigates the vibration reduction performance of bearings integrated with squeeze film dampers (SFDs) and active magnetic bearings (AMBs) in a simplified rotor-bearing system. The integration of SFDs and AMBs is proposed to leverage their complementary characteristics and enhance vibration suppression. A theoretical model is developed to analyze the dynamic behaviour of the system, and the effects of various parameters on vibration reduction are examined. The results demonstrate that the combined use of SFDs and AMBs can significantly reduce vibration amplitudes and improve system stability. The findings of this study provide valuable insights into the design and optimization of rotor-bearing systems with enhanced vibration reduction capabilities

Introduction

The text discusses Active Magnetic Bearings (AMBs) and their role in improving the dynamic performance of rotating machinery, with a comparative study against Squeeze Film Dampers (SFDs). AMBs levitate the rotor using magnetic forces, eliminating physical contact and offering advantages such as high-speed capability, low wear, tunability, and reduced power loss. Their operation relies on a closed-loop control system using sensors, controllers, power amplifiers, and electromagnetic coils, with PID control commonly applied to maintain rotor stability.

The hardware of AMBs includes multiple electromagnetic coils (typically four in radial AMBs), power amplifiers, position sensors (most commonly eddy current sensors), and auxiliary touchdown bearings for safety during power failure. AMBs are widely studied for vibration control, fault detection, and diagnostics, and have applications in high-speed machinery, pumps, compressors, and aerospace systems.

The study’s main objective is to perform a dynamic analysis and performance comparison between two rotor-bearing systems:

• Rotor-1 supported by rolling element bearings with SFDs

• Rotor-2 supported by AMBs

Mathematical models for shafts, discs, bearings, SFDs, AMBs, and unbalance forces are developed and integrated to form global equations of motion. These models are implemented in Simulink to analyze time-domain responses and critical speeds.

Results show that the rotor system exhibits critical speeds around 3090 rpm and 8234 rpm. For SFD-supported systems, parametric studies reveal that increasing radial clearance or land width increases damping and reduces vibration amplitudes up to an optimal level. Beyond this optimum, excessive damping stiffens the system and can increase vibration amplitudes. SFDs behave linearly up to an eccentricity ratio of about 0.5, after which nonlinear effects dominate.

Conclusion

This study dives into how squeeze film dampers (SFDs) and active magnetic bearings (AMBs) impact a rotor system featuring two discs—think of it as a high-speed spinning shaft setup common in turbines or engines.Modeling the Rotor We broke down the rotor using Timoshenko beam elements for accuracy, accounting for shear and rotary inertia. Unbalance forces from uneven mass distribution drive the external excitation. Global equations pull together the mass, stiffness, and gyroscopic matrices from both the shaft and discs.Baseline Critical Speeds The undamped version shows critical speeds at roughly 3090 rpm and 8234 rpm. At the first one, vibrations hit a peak of 322 microns—enough to worry about in real machinery.Squeeze Film Dampers in Action Placing SFDs at the bearings introduces viscous damping. Parametric tests varied clearances and lengths, revealing linear damping up to 0.5 eccentricity ratio; past that, nonlinear effects are significant. While these dampers initially reduce vibrations, excessively increasing the damping coefficient can induce \"lock-up,\" causing the damper to behave as a rigid link, which in turn increases vibration amplitudes. Active Magnetic Bearings EdgeAMBs at the bearings offer tunable control via PID gains. Proportional gain shifts resonant speeds effectively; integral gives a slight shift plus amplitude reduction; derivative mirrors that. The AMBs adapt dynamics without hardware swaps, positioning them as a flexible SFD replacement for smarter rotor control.

References

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Copyright

Copyright © 2026 Manoj Kumar Saddala, S. Anil Kumar, K. Sateesh Kumar Reddy. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.