摘要:

A procedure for the numerical solution of the complete isothermal elastohydrodynamic lubrication problem for line contacts is outlined. This procedure calls for the simultaneous solution of the elasticity and Reynolds equations. In the elasticity analysis, the conjunction is divided into equal rectangular areas. It is assumed that a uniform pressure is applied over each area. In the numerical analysis of the Reynolds equation, the parameter π = QH3/2is introduced in order to help the relaxation process. The analysis couples the elasticity and Reynolds equations, going from the inlet to the outlet without making any assumptions other than neglecting side leakage.

ISSN:0569-8197    

DOI:10.1080/05698198408981572

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The contact area of the plate of a ball/plate (both consisting of hardened M-50 steel) sliding elastohydrodynamic contact run on trimethylolpropane triheptanoate with or without tricresylphosphate (TCP) additive was optically profiled periodically with a phase-locked interference microscope (PLIM), both before and after exposure to alcoholic hydrochloric acid. As scuffing was approached, the change of profile within the contact region changed much more rapidly by the acid probe and assumed a constant high value after scuffing. A new nonetching metallurgical phase was found in the scuff mark, which was apparently responsible for the high reactivity. Soaking the metal surfaces in the lubricant before running affected the subsequent reactivity.

ISSN:0569-8197    

DOI:10.1080/05698198408981573

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Sliding-friction experiments, X-ray photoelectron spectroscopy (XPS) analysis, and electron microscopy and diffraction studies were conducted with ferrous-base metallic glasses (amorphous alloys) in contact with aluminum oxide at temperatures to 750°C in a vacuum. Sliding-friction experiments were also conducted in argon and air atmosphere.

ISSN:0569-8197    

DOI:10.1080/05698198408981574

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The effect of extremely small slip amplitudes (0 to 5 μm) on transitions in the fretting process, such as initiation of surface damage, development of severe surface damage, microcrack initiation and the development of mild wear, was investigated. For SAE 52100 against SAE 52100 steel, the minimum slip amplitude associated with the onset of mild oxidation or surface staining was approximately 0.06 μm. Studies at higher amplitudes of motion indicated a transition from minimal surface damage to severe or significant damage at 2.8 μm. A further slight increase in amplitude to approximately 3.0 μm resulted in a transition into a regime characterized by fatigue crack formation. These transformations were found to be influenced to some extent by material composition and hardness. The onset of severe surface damage occurred at 1.1 μm for SAE 52100 against SAE 1018 and at 0.5 μm for a nickel chrome Hastelloy B alloy against SAE 1018 steel. In general, the amplitude of microslip characterizing the transition from extremely mild to severe surface damage was found to increase with increasing material hardness.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:10.1080/05698198408981575

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Ultrahigh-molecular-weight polyethylene (UHMWPE) and polycarbonate were slid dry against continuous graphite fiber/epoxy plates in reciprocating multiple-pass tests for different values of fiber orientation, virgin surface roughness, and normal load. Regression equations were developed from the data relating the coefficient of friction and wear rate to fiber orientation and virgin surface roughness. The wear rate and coefficient of friction were plotted versus fiber orientation and virgin surface roughness to form three-dimensional friction and wear “surfaces.” Semiempirical friction and wear “surfaces” were found to be a convenient and compact method of presenting the complex data. Local maximum and minimum points could be easily identified and differences in the tribological properties of different materials became readily apparent.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:10.1080/05698198408981576

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The analysis and design of a 50-mm diameter floating-ring helium buffer seal are described. The seal rings incorporated Rayleigh-step lift pads to provide hydrodynamic forces to separate the rings from the shaft. Maximum surface speed is 183 mls (600 fps) and maximum buffer gas pressure is 1389 kPa (200 psia).

ISSN:0569-8197    

DOI:10.1080/05698198408981577

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

It is generally recommended by most manufacturers to keep working pressures of O-ring seals below 10 MPa (20 MPa with backup rings) and clearances below 0.15 mm, or else they might fail by extrusion. For many applications, and especially for large one-shot impact devices, these limits are much too low, and more realistic limits may be set through better understanding of the failure modes.

ISSN:0569-8197    

DOI:10.1080/05698198408981578

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Three types of journal bearing of circular bore, elliptical, and offset-halves designs were subjected to excitation tests over a wide range of frequency. It is shown that, in the stable region of operation, the amplitude of the response correlates reasonably well with the solutions of linear theory. The response was found to peak (strongly in some cases) at excitation frequencies in the range 0.43 to 0.75 of the shaft running speed, depending on design and distance of the operating point from the instability threshold. These observed natural frequencies were found to correlate well with linear theory solutions for lower range frequency values up to about 0.65. At higher predicted natural frequencies, the observed resonance was less than the theoretical solutions.

ISSN:0569-8197    

DOI:10.1080/05698198408981579

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The significantly higher oxidation stability obtained on deuteration of the acid moiety of a neopentyl polyol ester is the result of two effects, viz, the deuteration effect and the synergistic effect of alkali metal compounds with the antioxidant. The enhancement in oxidation stability attributable to 96 atom percent deuteration appears to be three-to-fourfold at 220°C. The enhancement due to the alkali metal effect appears to be about thirtyfold. Preliminary results indicate that at higher deuterium concentration levels (>96 atom percent), the oxidative stability of the ester, deuterated on the acid moiety, is further increased.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:10.1080/05698198408981580

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Timken and Four-ball Machine tests were used to study the effects of the dodecyl amine salt of benzotriazole (ASBT) on the lubricity of liquid paraffin containing sulfurized olefin (SO). The wear rate and friction coefficient decreased in the presence of ASBT. The tribochemical reactions of both ASBT and SO were studied with the aid of modern physical techniques, such as AES, ESCA, IR spectroscopy and scanning electron microscopy.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:10.1080/05698198408981581

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor