摘要:

Displacement equations for static conical seal structures were solved by the Ritz-Galerkin finite element method. The constitutive equation was Hooke's law with the plane stress assumption. Finite strains relative to the initial or free configuration were used in conjunction with the strain-dependent modulus of the material. The nonlinearity of the transverse shear stress resultant or radial load thus predicted, was in exact agreement with the experiment almost up to the maximum possible displacement. The mechanism by which the radial load became nonlinear was not simply additive in the geometric and material contributions. Instead, the geometric non-linearity, while having a negligible effect by itself on the radial load, had the property of more than doubling the maximum strain in the structure, therefore amplifying the effect of the strain-dependent modulus on the radial load. Both local and global algorithms for solving nonlinear equations gave the same results, suggesting that the solution found was unique. Experimental radial loads of seal structures with radius-to-thickness ratios between 6 and 42 were favorably predicted by the program. Measured seal thermal expansions were also in very good agreement with program predictions.

ISSN:1040-2004    

DOI:10.1080/10402009208982159

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

An experimental investigation to determine the effects of surface roughness lay direction relative to the direction of motion on initial surface damage was conducted using a four-ball machine under both simple sliding and pure rolling point contact conditions. Surface topographies ranging from 0.11 μm (4.45 μm) to 0.73 μm (28.61 μm.) RMS roughness and 31.5 μm (1239 μin.) to 59.6 μm (2345 μin.) in wavelength were utilized in the experimental program. A lithium complex grease was used as the lubricant for all tests. The experimental results indicate that surfaces with transverse lay orientations cause more initial surface damage than surfaces with longitudinal lay orientations for relatively low ratios of film thickness-to-composite surface roughness, and low ratios of surf ace wavelength-to-contact radius.Presented at the 47th Annual Meeting in Philadelphia, Pennsylvania May 4–7, 1992

ISSN:1040-2004    

DOI:10.1080/10402009208982160

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Two types of ceramic materials, zirconia-toughened alumina (ZTA), and transformation-toughened zirconia (TTZ—yttria stabilized zirconia), were evaluated as cam roller followers in simulated valve train tests and were compared to silicon nitride (Si3N4) roller followers. These tests were conducted to determine the short-term durability of these ceramics and to determine their efficacy as cam roller followers. A weight gain of approximately 10−4g occurred on each type of ceramic material. This was caused by a polishing action on the driving ring specimen, made of AISI 52100 steel, and the formation of a transfer film. The friction coefficients ranged between 0.041 and 0.071, correlating closely to theoretical predicted values of approximately 0.064. A relative ranking of the materials could only be made by the change in surface roughness on the steel ring, as weight loss was not measured. The asperity tips on the steel rings exhibited a greater amount of polishing wear and lower roughness values when tested against the ZTA and Si3N4, while the rings tested against the TTZ ceramics exhibited little wear.Presented at the 47th Annual Meeting in Philadelphia, Pennsylvania May 4–7, 1992

ISSN:1040-2004    

DOI:10.1080/10402009208982161

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This study identifies factors that affect slider performance and reports the effect of the nature of slider materials on wear behavior. Three factors relating to wear behavior are discussed: slider shape, wear data reproducibility and patterns of wear behavior. First, the performance of various sliders shows a strong correlation to the slider crown shape. Second, wear behavior is more reproducible when unlubricated disks replace lubricated disks. With lubricated thin-film disks, slider failure is reasonably reproducible, but when the failure occurs it is erratic. Although unlubricated disks show more reproducible wear data, the wear life of the disks is roughly an order of magnitude shorter than lubricated disks. It is important to recognize these factors before evaluating material differences in slider performance. Finally, multi-phase slider materials have more variation in failure patterns than single-phase slider materials; the difference is attributed to more flaws present in the multi-phase material.Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference in Toronto, Ontario, Canada, October 8–10, 1990

ISSN:1040-2004    

DOI:10.1080/10402009208982162

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

“Smart” materials and structures are characterized by their ability to sense, actuate, or control, either by themselves or through imbedded sensors, and are thus capable of adapting themselves to changes in external conditions to maintain a specified goal. In particular, electrorheological fluids have properties which can change in an electric field. A solution of the lubrication equation for ER fluids is developed to investigate controllability of the stability properties of ER fluid bearings. It is found that the properties of such bearings can be changed considerably by an applied electric field and the stability region can be extended substantially.Presented at the 45th Annual Meeting in Denver, Colorado May 7–10, 1990

ISSN:1040-2004    

DOI:10.1080/10402009208982163

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

In this paper, dynamic behavior of elliptical journal bearings in the turbulent inertial flow regime was examined theoretically based on the nonlinear analysis for three different ellipticity ratios of m = 0, 0.5 and 1.0. The nonlinear equations of motion for a rigid shaft supported on two identical aligned bearings were solved by the improved Euler's method, and the relations between the transient journal center motion and the corresponding pressure distribution were presented in the graphic form. From the numerical results, the effects of ellipticity ratio, turbulence, and fluid film inertia on the dynamic behavior of elliptical journal bearings were clarified.Presented at the 45th Annual Meeting in Denver, Colorado May 7–10, 1990

ISSN:1040-2004    

DOI:10.1080/10402009208982164

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Previous work conducted on hybrid journal bearings has shown that a combination of hydrostatic and hydrodynamic lubrication principles leads to good load support over a wide range of speeds, including zero speed. Above the transition speed, particularly with large bearing diameters or low-viscosity lubricants, the mode of flow within the fluid film degenerates from that of pure laminar flow, through a transitional or vortex flow regime, to fully developed turbulent flow. This work presents a theoretical investigation of slot entry hybrid journal bearings operating in the superlaminar flow regimes. In particular, the work considers the effects of superlaminar flow on the optimization of slot entry hybrid journal bearings.

ISSN:1040-2004    

DOI:10.1080/10402009208982165

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A new testing device has been developed to investigate the mechanism of friction and lubrication in the deep drawing process. The friction force occurring in the flange part of the cup is measured directly. The friction coefficient associated with the surface texture was assessed by means of eddy-current measurements. The relevant factors likely to affect the frictional resistance at the tool-metal interface include the clamping force, drawing speed, lubricant, and surface roughness. Another of the factors is related to the frictional characteristics of a lubricating layer in the flange area. Evidence for this was obtained by examining the topographic variation of the worn surface during the deep drawing process.

ISSN:1040-2004    

DOI:10.1080/10402009208982166

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Triboemission of charged particles and photons from Si3N4, Al2O3, ZrO2, and glass was investigated under He, Ar, N2, O2, dry air, and wet air atmospheres using a specially-developed triboemission measuring system for charged particles and photons.

ISSN:1040-2004    

DOI:10.1080/10402009208982167

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Eight different polymers were coated on beryllium surfaces by glow discharge polymerization in an inductively coupled tubular reactor. Using a pin-on-disk apparatus, friction tests were then conducted on the polymer-coated beryllium disks with Pyroceram pins. Of all the coated surfaces, polyethylene-coated beryllium exhibited the lowest friction with no measurable wear. The friction coefficient of the polyethylene-coated beryllium surface was found to depend strongly on the film thickness. The variation of friction coefficient with film thickness was analyzed, and a reasonable agreement between theoretical prediction and experimental data was obtained.

ISSN:1040-2004    

DOI:10.1080/10402009208982168

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor