Crack Face Friction Effects on Mode II Stress Intensities for a Surface-Cracked Coating in Two-Dimensional Rolling Contact

Abstract

This work focuses on the effects of crack free friction on Mode II stress intensity factors, K_II, for a vertical surface crack in a two-dimensional finite element model of TiN/steel subject to rolling line contact. Second-order extrapolation of K_I and K_II from nodal stresses ahead of the crack tip is found to be a more consistent technique than linear extrapolation. Results indicate that maximum KJJ values, which occur when the load is adjacent to the crack, may be significantly reduced in the presence of crack face friction. The reduction is more significant for thick coatings than for thin. Crack extension and increased layer thickness result in increased K_II values. The effect of crack face friction on compressive K_I values appears negligible. Comparative results are presented for MoS₂/steel and diamond-like carbon/Ti systems.

Presented at the 51st Annual Meeting in Cincinnati, Ohio May 19–23, 1996

KEY WORDS:

• Tribology
• Crack Propagation
• Surface Films/Coatings
• Stress Analysis
• Contact Mechanics

Notes

Presented at the 51st Annual Meeting in Cincinnati, Ohio May 19–23, 1996