Recent Highlights
Annex
III | Annex IV | Recent
Reports
Annex
III: Cooperative Program on Contact Reliability of Advanced
Engine Materials
Rolling Contact Fatigue
A “C-Sphere” flexure strength specimen geometry
was developed to measure a relevant strength of bearing-grade
Si3N4 balls and to relate that to surface flaws and to
ultimately link those flaw populations to rolling contact
fatigue performance. A slot was machined into the balls
to a set depth to produce the C-sphere geometry. C-sphere
specimens were then diametrically compressed to produce a
monotonically increasing flexure or hoop tensile stress
at their surface that caused their fracture. The strength
was determined using the combination of failure load, C-sphere
geometry, and FEA, and the stress field was used to determine
C-sphere effective areas and effective volumes as a function
of Weibull modulus. A description of the specimen and the
aforementioned analysis are provided and a comparison of
C-sphere flexure strength distributions of two bearing
grade Si3N4 materials (NBD200 and SN101C) is given.
Preprint of Cocoa Beach 2006 Proceedings Paper on C-Sphere
Flexure Strength
Rolling Contact Fatigue of Ceramics, Aug. 2006
Annex
IV: Co-operative Program on Integrated Engineered Surface
Technology
- Simultaneous theoretical modeling and experimental
research in the high load, low speed contact conditions
- Demonstration of texture effects on steel-on-steel
contact with the pressure in GPa range
- Developing 3-D topography representation of textured
surfaces
- Test methods for textured surfaces is important to
control wear-in
- Coatings and chemical protection films need to be developed
for the textures
Surface Texturing: Principles and Design, Nov. 2006
Recent
Reports
Annual IA-AMT Reports
Annual DOE Reports
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