The role of oil seepage in fatigue crack growth of lubricated wearing systems

• Published in: Engineering fracture mechanics 1998-05, Vol.60 (2), p.239-250
• Main Authors: Omidvar, Bijan, Ghorbanpoor, Al
• Format: Article
• Language: English
• Subjects: oil-seepage, fatigue, crack growth, lubricated wearing system, tribology, pitting, sliding contact, asperity
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/S0013-7944(98)00002-2

Lubricated rolling/sliding systems routinely undergo significant repair and replacement with substantial associated cost, due to cracking and pitting damages. While it is understood that these damages could be related to the effect of lubricating oil seepage inside cracks, to date no proper analytical solution for this special liquid–solid interaction problem has been presented. This paper discusses the role of oil seepage in fatigue crack growth of a lubricated sliding wear system. The problem of contact with asperities and pre-existing surface crack perpendicular to the contact surface in sliding wear, is analyzed by finite element method. In calculations, the incompressibility of the working fluid was assumed to determine the hydrostatic pressure between the crack faces during contact wearing. A parametric study is performed to investigate the effect of the length of each contacting asperity relative to the crack length, coefficient of friction and number of asperities between the contact surfaces, on the stress intensity factor K I and the oil pressure inside the crack. It is found that the lubricating oil seepage can significantly excite and accelerate the fatigue crack growth in wearing systems. From the results of this study, the effect of the lubricating oil seepage on pitting phenomenon can be clearly explained.