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Results for “SLIDING CONTACT”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Friction and morphology of magnetic tapes in sliding contact with nickel-zinc ferrite

Friction and morphological studies were conducted with magnetic tapes containing a Ni-Zn ferrite hemispherical pin in laboratory air at a relative humidity of 40 percent and at 23 C. The results indicate that the binder plays a significant role in the friction properties, morphology, and microstructure of the tape. Comparisons were made with four binders: nitrocellulose; poly (vinyledene) chloride; cellulose acetate; and hydroxyl-terminated, low molecular weight polyester added to the base polymer, polyester-polyurethane. The coefficient of friction was lowest for the tape with the nitrocellulose binder and increased in the order hydroxylterminated, low molecular weight polyester resin; poly (vinyledene) chloride; and cellulose acetate. The degree of enclosure of the oxide particles by the binder was highest for hydroxyl-terminated, low molecular weight polyester and decreased in the order cellulose acetate, poly (vinyledene) chloride, and nitrocellulose. The nature of deformation of the tape was a factor in controlling friction. The coefficient of friction under elastic contact conditions was considerably lower than under conditions that produced plastic contacts.

Miyoshi, K.↗
NASA NTRS1991

Elasto-plastic coupled temperature-displacement finite element analysis of two-dimensional rolling-sliding contact with a translating heat source

The present paper describes a transient translating elastoplastic thermomechanical finite element model to study two-dimensional frictional rolling contact. Frictional two-dimensional contact is simulated by repeatedly translating a nonuniform thermomechanical distribution across the surface of an elastoplastic half space. The half space is represented by a two-dimensional finite element mesh with appropriate boundaries. Calculations are for an elastic-perfectly plastic material and the selected thermophysical properties are assumed to be temperature independent. The paper presents temperature variations, stress and plastic strain distributions and deformations. Residual tensile stresses are observed. The magnitude and depth of these stresses depends on (1) the temperature gradients and (2) the magnitudes of the normal and tangential tractions.

Rubin, C. A.↗
DOE OSTI2024

Minimal contact slide for touch indication

A nozzle holder assembly for a three-dimensional printer comprises a mount, a printer nozzle, and a locking mechanism. The mount is operable to be secured to the three-dimensional printer. The printer nozzle shaft is movably coupled to the mount along a predetermined length. The locking mechanism is configured to fix the printer nozzle shaft relative to the mount at any position along the predetermined length.

Pino, Ruben A.↗
NASA NTRS1966

Sliding electrical contact materials

The results of research programs to develop sliding electrical contact materials, both brushes and slip rings, are discussed. Problems attendant to operating sliding contacts in a vacuum are defined; limitations of commercial materials in solving these problems are described, and special materials and surface finish conditions which have resulted in solutions to these problems are presented. Data from operational tests on the newly developed materials are compared with similar data obtained from materials now used as standards in consumer products. Possible commercial applications of the more efficient sliding contact materials are discussed briefly.

Sliding contact↗
DOE OSTI2012

On estimations of maximum and average interfacial temperature rise in sliding elliptical contacts

his study considers the approaches of Blok and Jaeger for the estimation of maximum and average temperatures in sliding elliptical contacts with both uniform and semi-ellipsoidal (Hertzian) heat distributions. The accuracy of each of these methods, which are based on single-point temperature matching between contacting bodies, is assessed relative to a numerical solution of the heat partition problem developed in a previous work, which imposed temperature matching at all nodal points. Comparisons are made for a wide range of Peclet numbers, as well as for moderate ranges of thermal conductivity ratio and elliptical ratio. It is found that the application of Blok's hypothesis yields remarkably accurate predictions of the maximum interfacial temperature, with typical errors less than 3%, whereas the hypothesis of Jaeger leads to predictions of the average interfacial temperature that have typical errors of around 6%. The authors also assess the accuracy of approximate formula developed by Tian and Kennedy to predict the maximum temperature at the interface for the case of sliding circular contacts and find the error to be no more than 2.6% for the full range of Peclet number. Further, the authors of the current study use fundamental heat source solutions developed by Tian and Kennedy to arrive at formulae for average temperature rise for circular contacts that are analogous to the Tian and Kennedy maximum temperature rise formulae. It is found that the formulae for computing the average interfacial temperature rise are also quite accurate, but have slightly more error than the maximum temperature rise formulae. Finally, in the present work, extensions are suggested to the maximum and average temperature rise formulae of Tian and Kennedy to include the effects of elliptical contact geometry. It is found that these formulae are at least 91% accurate for elliptical ratios between 0.4 and 5.0.

99 GENERAL AND MISCELLANEOUS↗
NASA NTRS1978

Anisotropic friction and wear of single-crystal manganese-zinc ferrite in contact with itself

Sliding friction experiments were conducted with manganese-zinc ferrite (100), (110), (111), and (211) planes in contact with themselves. Mating the highest-atomic-density directions, (110), of matched crystallographic planes resulted in the lowest coefficients of friction. Mating matched (same) high-atomic-density planes and matched (same)crystallographic directions resulted in low coefficients of friction. Mating dissimilar crystallographic planes, however, did not give significantly different friction results from those with matched planes. Sliding caused cracking and the formation of hexagonal- and rectangular-platelet wear debris on ferrite surfaces, primarily from cleavage of the (110) planes.

Miyoshi, K.↗