Dynamic Modeling and Analysis of Rotary Joints with Coupled Bearing Tilt-Misalignment Faults.

Area of Science:

• Mechanical Engineering
• Vibration Analysis
• Fault Diagnosis

Background:

• Rotary joints are critical components in many mechanical systems.
• Bearing faults, particularly those involving tilt and misalignment, can lead to system failure.
• Accurate dynamic modeling is essential for predicting and diagnosing these faults.

Purpose of the Study:

• To develop a high-fidelity nonlinear dynamic model for a dual-support bearing-rotor system with tilt-misalignment coupling faults.
• To analyze the influence of tilt angle and misalignment magnitude on system dynamics.
• To provide a theoretical basis for the health monitoring and intelligent diagnosis of rotary joints.

Main Methods:

• Integration of Hertzian contact theory to model nonlinear contact forces.
• Derivation of bearing forces considering time-varying stiffness and radial clearance.
• Application of the Newmark-β numerical integration method to solve vibration response.
• Gaussian filtering to simulate defect surface roughness and analyze fault modulation effects.

Main Results:

• The study quantifies the impact of tilt angle and misalignment on contact forces and vibration patterns.
• Multi-frequency harmonic characteristics and nonlinear amplitude growth with misalignment were observed.
• Dynamic models for single-point and composite faults were established.
• Experimental validation confirmed the model's accuracy in capturing vibration features.

Conclusions:

• The developed nonlinear dynamic model accurately represents the behavior of bearing tilt-misalignment coupling faults.
• The findings highlight the complex vibrational responses induced by misalignment.
• This research offers a robust theoretical foundation for advanced health monitoring and intelligent diagnosis of rotary joints.