The Entrainment of Solid Particles into Rolling Elastohydrodynamic Contacts

Dwyer-Joyce, R. S.; Heymcr, J.

doi:10.1016/s0167-8922(08)70777-6

Cited by 26 publications

(21 citation statements)

References 6 publications

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“…Counting the number of surface dents on a rolling element has been used [2] to determine the proportion of particles in a lubricant supply that enter a contact. A simple ball on flat rolling contact was used with low levels of contamination with diamond particles (which would not fracture and so lead to multiple indentations).…”

Section: Indent Counting Experimentsmentioning

confidence: 99%

The Life Cycle of a Debris Particle

Dwyer-Joyce

2005

Tribology and Interface Engineering Series

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Debris particles exist in most lubrication systems; they are frequently responsible for the early failure of tribological machine elements. Particles come from the surrounding environment, or may be generated within the machine components. As the lubricant circulates, these particles get flushed into the machine elements. Contact pressures are high and oil films are small, so that the relatively large particles damage even the hardest gear, bearing, or cam surface. This damage can lead to contact fatigue or wear, and thus premature failure of the whole machine. Further, one failure can result in the generation of further wear debris, often in very great quantities, that then can have a knock-on effect in other parts of the lubricated system. This paper gives an overview of important features of the life cycle of a debris particle; entrainment of debris particles into a contact, resulting surface damage, shortened component life, and debris particle procreation by fatigue and wear. The debris life cycle coincides with the early mortality of the machine element. The methods by which component life, under particulate contaminated conditions, can be determined are reviewed.

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Section: Indent Counting Experimentsmentioning

confidence: 99%

The Life Cycle of a Debris Particle

Dwyer-Joyce

2005

Tribology and Interface Engineering Series

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“…The number of particles which take part in this material removal process must be estimated. Previous work [5] has shown that it is not safe to assume that the concentration of particles in the contact is the same as that in the bulk. Experimental data shows how the contact can have a particle concentrating effect which varies with particle size and contact speed.…”

Section: Number Of Particles Entering the Contactmentioning

confidence: 99%

“…The particle entry ratio φ is approached empirically. A separate study [5] has been carried out for this purpose. The apparatus consisted of a steel ball loaded onto a flat steel disk and run in pure rolling with a lubricant mixed with diamond particles of known size.…”

Section: Number Of Particles Entering the Contactmentioning

confidence: 99%

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Predicting the abrasive wear of ball bearings by lubricant debris

Dwyer-Joyce

1999

Wear

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Solid debris particles in a lubricant can become entrained into the contacts of ball bearings. The particles damage the bearing surfaces. This can lead to rolling contact fatigue failure or material loss by three body abrasion. This work concentrates on modelling the later process for brittle debris materials. A brittle particle is crushed in the inlet region and the fragments are entrained in to the contact. Rolling bearing contacts (because of the high degree of conformity) are subject to contact microslip. When this slip takes place, the trapped particle scratches the bearing surfaces. Repeated scratching by many particles results in substantial material removal. Although this failure mechanism is usually not as rapid as debris initiated fatigue, it is frequently important in mineral handling or desert environment rolling bearing applications. A simple model has been developed which considers the wear as the sum of the individual actions of each particle. The number of debris particles is determined by considering the volume of oil entrained into the bearing contacts and an empirically derived Ôparticle entry ratioÕ. The abrasive action of each particle is determined by the volume of material displaced during sliding and another empirical factor for the proportion of this removed as a wear particle. The predictions are compared with some experimental results. The correlation between bearing wear and the debris particle size is encouraging.

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“…The effect of a dent on the EHL lubrication of a line or point contact was the subject of many investigations starting from late 70s, first experimentally [10][11][12][13] and later numerically [14][15][16]. Experimental and theoretical work on particle entrapment in the EHL conjunction, particle deformation and debris denting [17][18][19][20][21][22][23][24][25][26], and subsequent wear or fatigue life reduction [27][28][29][30][31][32][33][34][35][36][37][38] has then been a hot research topic and especially welcomed by leading bearing manufacturers and academia. The first attempts to quantify the effects of lubricant cleanliness on the fatigue life reduction are due to Tallian [27,28].…”

Section: Introductionmentioning

confidence: 99%

Contact Fatigue Analysis of a Dented Surface in a Dry Elastic–Plastic Circular Point Contact

Antaluca

Nélias

2008

Tribol Lett

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The present article proposes a methodology for the computational analysis of damage induced in the vicinity of dents in a dry circular point contact under repeated rolling. The failure risk is evaluated through the use of the Dang Van multiaxial fatigue criterion. The dent is a typical surface defect encountered in rolling element bearings when operating in contaminated environments. It is usually created by a solid particle not removed by seals or filters when passing through an EHL conjunction. Since local plasticity occurs when the debris is first entrapped between the contacting surfaces, and later when the resulting dents are subjected to moving contact load, the elastic-plastic behavior of the material should be captured by the model. First, the dent shape and the subsurface stress and strain fields produced by the presence of a spherical particle are obtained by the finite element method. Second, the rolling of the load over the surface defect is simulated using a semi-analytical elastic-plastic code. The simulations are carried out for two different debris materials, both ductile but one significantly softer than the contacting surfaces, i.e., made of stainless steel 316L, the other one being made of bearing steel AISI 52100 similar to the contacting surfaces. The dent shape and initial stress and strain states are first presented. Subsequent stress and strain states after a few rolling cycles are then presented. Finally the effects of the coefficient of friction, presence of residual stress, and contact load magnitude are highlighted.

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The Entrainment of Solid Particles into Rolling Elastohydrodynamic Contacts

Cited by 26 publications

References 6 publications

The Life Cycle of a Debris Particle

The Life Cycle of a Debris Particle

Predicting the abrasive wear of ball bearings by lubricant debris

Contact Fatigue Analysis of a Dented Surface in a Dry Elastic–Plastic Circular Point Contact

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