Kenneth W. Burris

Modern State of Experimentation and Modeling in Contact Fatigue Phenomenon: Part II—Analysis of the Existing Statistical Mathematical Models of Bearing and Gear Fatigue Life. New Statistical Model of Contact Fatigue

The paper presents a critical analysis of some existing statistical mathematical models of fatigue life applicable to bearings and gears, i.e. the assumptions, advantages, disadvantages and several contradicting aspects of these models. Some conclusions that adequately reflect the experimental and theoretical data discussed in Part I are drawn regarding the necessary features of a successful mathematical model of contact fatigue. Furthermore, such a new statistical model that will allow to predict fatigue life of machine parts is proposed in this paper. It is based on the first five parameters from the list compiled by Kudish and Burris (2000a) that are known to strongly affect contact fatigue. The other parameters from this list can be subsequently incorporated into the model. The paper also presents a theoretical analysis of the new model and some numerical results for contact fatigue life based on this model. Presented as a Society of Tribologists and Lubrication Engineers Paper at the STLE/ASME Tribology Conference in Orlando, Florida, October 11–13, 1999

Modern State of Experimentation and Modeling in Contact Fatigue Phenomenon: Part I—Contact Fatigue. Normal and Tangential Contact and Residual Stresses. Nonmetallic Inclusions and Lubricant Contamination. Crack Initiation and Crack Propagation. Surface and Subsurface Cracks

The purpose of this paper is to describe the modern understanding of the contact fatigue phenomenon which occurs in different materials under various loading conditions. Part I presents experimental and theoretical knowledge of the influence of normal and factional contact and residual stresses on contact fatigue. It analyzes relationships between contact fatigue and material defects, inclusions, and lubricant contamination. Furthermore, it discusses crack initiation and crack propagation, the effect of material microstructure on contact fatigue life as well as some theoretical results for surface and subsurface cracks. Part II is devoted to reviewing the existing mathematical models of fatigue life for bearings and gears and to describing a new statistical model of contact fatigue based on contact and fracture mechanics. This new model is based on the assumptions derived from the analysis of the data presented in Part I. Presented as a Society of Tribologists and Lubrication Engineers Paper at the STLE/ASME Tribology Conference In Orlando, Florida, October 11–13, 1999