摘要:

Sterntube bearings are commonly subjected to significant static and dynamic angular misalignment by the adjacent propeller. Results of a theoretical investigation into the performance of oil-lubricated sterntube bearings with static misalignment are reported. In addition, 32 oil film force and moment coefficients, which fully define the response to both lateral and angular motion of the journal axis, are presented. Limitations to the application of these coefficients arising from their nonlinearity are discussed. A practical sterntube bearing analysis program is described which utilizes computed dimensionless performance data. This program determines the effective oil film viscosity via an iterative heat balance procedure, and thus simulates the operating conditions of a real bearing. Results produced by this program are included, and give a realistic indication of the effect of L/D ratio variation for a range of misalignment angles.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Tribology Conference in Atlanta, Georgia, October 8–10, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981706

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A synergistic effect was observed for systems of phosphites and sulfur-type additives, while no interaction was observed for systems of phosphates and sulfur-type additives. The mechanism of synergism was studied by EPMA, FT-IR, GC-FPD, and MS. From a synergistic mixture, a new compound containing phosphorus and sulfur was detected. The new compound which was separated by distillation showed good antiwear properties comparable with the synergistic system and was identified as a thiophosphate. The synergism between the sulfur-type additive and phosphite may be caused by the formation of thiophosphate. The chemical reaction between them is discussed and a reaction formula is proposed.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Tribology Conference in Atlanta, Georgia, October 8–10, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981707

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Ellipsometric analyses of wear tracks in bearings of M-50 steel were carried out after operation under severe conditions with different lubricant additives. The base lubricant was a synthetic ester. It was found that the surface and wear additives benzotriazole and tricresylphosphate produced very patchy oxide layers. Dioctyldiphenylamine, a common antioxidant, on the other hand produced smoother films. The analyses were performed with a specially designed and constructed ellipsometer of very high (20 μm) spatial resolution. The results are consistent with data obtained by Auger electron spectroscopy.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Tribology Conference in Atlanta, Georgia, October 8–10, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981708

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

In a mechanical face seal, the total applied load is supported by hydrostatic and hydrodynamic fluid pressures and often by partial contact of the seal faces. Hydrostatic load support is affected by the initial seal interface geometry and the modification of this geometry due to component distortions. A model developed for static (non-rotating) conditions demonstrates effects of face convergence, spring pressure, and secondary seal friction on the hydrostatic fluid film thickness.

ISSN:0569-8197    

DOI:10.1080/05698198608981709

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Cavitation erosion and erosion rates of eight metallic materials representing three crystal structures were studied. The erosion experiments were conducted with a 20-kHz ultrasonic electrostrictive oscillator in a viscous mineral oil. The erosion rates of the metals and alloys varied over three orders of magnitude. The erosion rates of brittle metals, iron, and molybdenum were higher than that of the titanium alloy but lower than the rest of the soft ductile metals and alloys. Studies with scanning electron microscopy indicated that the cavitation pits were initially formed at the grain boundaries and precipitates and that the pits formed at the junction of grain boundaries grew faster than the others. Transcrystalline craters formed by cavitation attack over the surface of grains and roughened the surfaces by multiple slip and twinning. Surface roughness measurements showed that the pits formed over the grain boundaries deepened faster than other pits. Computer analysis revealed that a geometric expression describes the normalized erosion curves during the time period 0.5 t0< t < 2.5 t0, where t0is the incubation period. The fcc metals had very short incubation periods; the titanium alloy had the longest incubation period.Presented as an American Society Of Lubrication Engineers paper at the ASLE/ASME Tribology Conference in Atlanta, Georgia, October 8–10, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981710

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The friction coefficient of hot-pressed Si3N4on itself was measured in the temperature range of 150 to 800°C. Sliding occurred in dry argon, dry and humid air and the sliding velocity was varied from 0.1 to 10 cm/s. In dry argon and dry air, the friction coefficient is f = 0.8 ± 0.05 over the whole temperature range and wear occurs by fracture as it does at room temperature.

ISSN:0569-8197    

DOI:10.1080/05698198608981711

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Long-term creep tests on poly(ethylene terephthalate) (PET) films were conducted at different temperatures and humidities. Shift factors were calculated using time-temperature and time-humidity superpositions. We found that the activation energy of PET films appears to be constant at the test conditions (below its glass-transition temperature). Using the temperature and humidity shift factors, the shift factor at any temperature and humidity can be predicted. Tests were conducted to study the viscoelastic behavior of PET films subjected to a time-dependent temperature field. Tests were also conducted to compare the viscoelastic behavior of coated tapes and uncoated PET substrates.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Tribology Conference in Atlanta, Georgia, October 8–10, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981712

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A solution scheme for the squeeze-film problem using the Newton-Raphson method with a tangential matrix is presented. The integration of elasticity equation is done with the aid of isoparametric elements and the film thickness under a sinusoidal load is obtained. A new squeeze-suction phenomenon which shows the possibility of maintaining fluid film under cyclic positive load conditions is observed for small load and period and large compliance parameter cases. This could be an interesting result in applications like the viscous hydroplaning.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Tribology Conference in Atlanta, Georgia, October 8–10, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981713

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Hydrostatic gas noncontact seals are becoming more widely used as high-speed shaft seals for gas turbomachinery. Previous work for incompressible flow has been adapted to cover the gas flow dynamics of a hybrid taper/flat face seal, and the equivalent annular arrangement.

ISSN:0569-8197    

DOI:10.1080/05698198608981714

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Experimental results of the velocity distribution in a grease-lubricated cylindrical sliding contact are obtained. A comparison is made with the theoretical results of a parabolic velocity distribution similar to that of a Newtonian fluid, derived from a Bingham plastic flow model. This equation compares very well with the experimental results.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Tribology Conference in Atlanta, Georgia, October 8–10, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981715

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor