摘要:

Tribological studies at 25°C in a 50 percent relative-humidity air atmosphere were conducted using hemispherically tipped 440C HT (high temperature) stainless steel pins sliding against ultrahigh-molecular-weight polyethylene (UHMWPE) disks. The results indicate that sliding speed, sliding distance, contact stress, and specimen geometry can markedly affect friction, UHMWPE wear, UHMWPE transfer, and the type of wear mechanisms that occur. Adhesion appears to be the predominant wear mechanism; but after long sliding distances at slow speeds, heavy ridges of transfer result which can induce fatiguelike wear on the UHMWPE disk wear track. In one instance, abrasive wear to the metallic pin was observed. This was caused by a hard particle embedded in the UHMWPE disk wear track. The origin of this particle was uncertain.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983

ISSN:0569-8197    

DOI:10.1080/05698198508981588

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

An attempt is made to correlate some morphological characteristics of pitting cracks with a simple asperity interaction model. The stress field created by a semispherical pressure is combined with the macroscopic Hertzian stress field. For the initiation of fatigue cracks, emphasis is given to two stresses: the maximum range of the superimposed average shear stress over a semicircular area inclined at an angle α to the rolling surface; and the maximum of the superimposed average normal stress over the same semicircular area. Possible mechanisms for initiation of surface pitting are proposed.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983

ISSN:0569-8197    

DOI:10.1080/05698198508981589

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

To understand the chemical behavior of EP additives in sliding contacts, the concept of an anionic mechanism of the elementary sulfur and organo-sulfur compounds has been proposed. The model is based upon the ionization of these compounds by the action of exoelectrons. It has been shown that disulfides exhibit more efficient EP performance than monosulfides because lower energy is needed for the formation of the same number of RSΘions from disulfides. The corrosive action of the elementary sulfur in the friction process can be explained by the formation of ions from SΘto S8Θ. An attempt to interpret the difference in EP performance of diphenyl sulfide and dibenzyl sulfide has also been made as well.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983

ISSN:0569-8197    

DOI:10.1080/05698198508981590

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Parametric evaluations, based on analytical simulations of the dynamic performance of a solid-lubricated ball bearing, indicate that, for prescribed operating conditions and lubricant traction behavior at the ball/race contact, a reduction in the ball/cage pocket and cage/race guiding land clearances result in an increased frequency of collision both at the ball/cage and cage/race interfaces. The actual magnitudes of the collision forces are relatively insensitive to these clearances. The reduced clearances also lead to a coning motion of the cage and tight clearances at both the cage pocket and guiding land result in adverse cage/race interaction, when the cage is outer-race guided for the typical turbine engine bearing considered in the paper.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983

ISSN:0569-8197    

DOI:10.1080/05698198508981591

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The interaction of perfluoropolyalkylether (PFPE) oil with ferric fluoride (FeF3) and other Lewis acids at elevated temperatures under inert atmosphere was investigated to determine whether the reaction results in lubricant degradation. At 35°C, ∼25°C below the onset of thermal degradation, PFPE'S reaction with FeF3yields acyl fluoride and ketone degradation products and also a decrease in the oil's number-average molecular weight. In the presence of small quantities of water, the acyl halide products hydrolyze, resulting in carboxylic acids. The oil's reaction with aluminum fluoride at 350°C and aluminum chloride at 200°C also causes it to degrade measurably. The results indicate that PFPE oil can degrade at estimated bearing asperity contact temperatures in the presence of FeF3.

ISSN:0569-8197    

DOI:10.1080/05698198508981592

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Experiments have been carried out on full-film journal bearings lubricated with a low-vapor pressure liquid metal (gallium-based alloy) in argon and high vacuum. Plain and spiral-groove bearings of relatively small size and without additional liquid sealing were selected. The effect of reactive gases on the liquid-metal confinement and the influence of liquid-metal properties on the loci of the shaft centers were studied.

ISSN:0569-8197    

DOI:10.1080/05698198508981593

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Reynolds' equation is separable into two single variable differential equations for the case of a hydrodynamic bearing with its lubrication film curved in one direction. One of the equations is not, in general, soluble analytically. A simple numerical solution of this equation is described. The solution depends only on the shape of the lubrication film and not on the ratio b/l where b is the pad breadth and l is its length. This means that a sequence of bearing parameters for a set of values of b/l can be calculated rapidly from the single numerical solution of the differential equation.

ISSN:0569-8197    

DOI:10.1080/05698198508981594

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Growth behavior of surface cracks formed on lubricated rolling-sliding contact surfaces is studied by calculating three-dimensional mixed-mode stress intensity factors KI, KII, and KIII.

ISSN:0569-8197    

DOI:10.1080/05698198508981595

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The paper presents the results of a numerical study concerning the combined effect of two-sided roughness and elasticity in a one-dimensional slider bearing. Based upon the assumption that Reynolds' equation holds in the presence of roughness, and wing Christensen's stochastic models for two-sided roughness, it is established that there is a strong interaction between the roughness and elasticity. The elasticity acts so as to decrease the roughness effects.

ISSN:0569-8197    

DOI:10.1080/05698198508981596

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A critical assessment of techniques used to measure the real area of contact has been conducted. The techniques that are found to be suitable to measure contact area between a polymeric magnetic medium and a mating hard surface are: electrical-contact resistance and two-beam optical interference. The limitation of the electrical-contact resistance is that both surfaces must be electrically conductive. This technique only provides semiquantitative information. The two-beam optical interference technique provides complete distribution of the asperity-contact areas. Limitations of this technique are that the mating member must be optically transparent and both surfaces must be smooth. A monochromatic light of wavelength 706 nm (red) and a glass slide of high refractive index (1.93) were found to be suitable for magnetic tapes under study. All measurement techniques suffer from overestimation of the real area of contact, especially in the case of smooth magnetic tapes. Calculations for overestimation of the real area of contact for typical magnetic tapes are presented.Presented at the 39th Annual Meeting in Chicago, Illinois, May 7–10, 1984

ISSN:0569-8197    

DOI:10.1080/05698198508981597

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor