New Damage Accumulation Model for Spall Propagation Mechanism in Bearing Raceways

Area of Science:

• Mechanical Engineering
• Materials Science
• Tribology

Background:

• Spalling is a primary failure mode in ball bearings, often leading to catastrophic system failure.
• Accurate prediction of bearing remaining useful life requires understanding spall progression.
• Developing prognostic tools for bearings necessitates a deep dive into spall deterioration mechanisms.

Purpose of the Study:

• To investigate the physics-based spall propagation mechanism in ball bearing raceways.
• To develop a foundational understanding for creating prognostic tools for ball bearings.
• To formulate a constitutive law for spall deterioration and estimate remaining useful life.

Main Methods:

• A physics-based model integrating dynamic and finite element analysis (FEA) was developed.
• Continuum damage mechanics (CDM) and fracture mechanics were embedded within the FEA framework.
• Two crack propagation approaches were employed: fracture mechanics and accumulated inelastic hysteresis energy CDM.

Main Results:

• Simulations revealed fragment formation involves coalescing surface and sub-surface cracks near the spall edge.
• The impact of the ball on the spall edge was shown to influence crack propagation and residual stress release.
• The accumulated inelastic hysteresis energy CDM approach successfully predicted fragment release.

Conclusions:

• The developed physics-based model accurately simulates spall propagation, validated by experimental data.
• Understanding crack initiation, propagation, and fragment release is crucial for bearing prognostics.
• This research provides a basis for improved bearing health monitoring and life prediction.