Critical Flaw Size in Silicon Nitride Ball Bearings

• Published in: Tribology transactions Vol. 53; no. 4; pp. 511 - 519
• Main Authors: Levesque, George A., Arakere, Nagaraj K.
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA Taylor & Francis Group 01.07.2010; Taylor & Francis; Taylor & Francis Inc
• Subjects: Applied sciences; Ball bearings; Contact stresses; Cracks; Exact sciences and technology; Fatigue failure; Finite element method; Finite Element Modeling; Fracture; Fracture mechanics; Fracture mechanics (crack, fatigue, damage...); Friction; Friction, wear, lubrication; Fundamental areas of phenomenology (including applications); Hybrid Ball Bearings; Machine components; Mathematical models; Mechanical engineering. Machine design; Nondestructive testing; Partial Cone Crack; Physics; Rolling Contact Fatigue; Silicon Nitride; Simulation; Solid mechanics; Stress Intensity Factor; Structural and continuum mechanics; Tribology; Roll contact fatigue; Rolling contact; Fracture; Hybrid Ball Bearings; Fatigue fracture; Modeling; Rolling bearing; Finite element method; Hydrodynamic lubrication; Ball bearing; Stress intensity factor; Hydrostatic lubrication; Hybrid bearing; Localization; Fretting fatigue; Silicon nitride; Partial Cone Crack; Mechanical contact; Friction; Surface defect; Rolling Contact Fatigue; Non destructive test; Finite Element Modeling; Crack; Tribology
• ISSN: 1040-2004; 1547-397X
• DOI: 10.1080/10402000903491291

Silicon nitride balls, used in hybrid ball bearings, are susceptible to failure from fatigue spalls emanating from preexisting partial cone cracks that can grow under rolling contact fatigue (RCF). We simulate the range of three-dimensional nonplanar surface flaw geometries subject to RCF to calculate mixed mode stress intensity factors to determine the critical flaw size (CFS) or the largest allowable flaw that does not grow under service conditions. The cost of nondestructive evaluation (NDE) methods for silicon nitride balls scales exponentially with decreasing CFS and increasing ball diameter and can become a significant fraction of the overall manufacturing cost. Stress intensity factor variability is analyzed for variations of the location and orientation of the load relative to the crack, the geometry of load, and full-slip traction. The modeling techniques utilized in the creation of a three-dimensional (3D) finite element analysis (FEA) model is discussed and the maximum tensile contact periphery stress is examined for effect on crack driving force under RCF. The CFS results are presented as a function of Hertzian contact stress, traction magnitude, and crack size.