Rolling-element fatigue and lubrication with fluorinated polyethers at cryogenic temperatures
Rolling ball fatigue and lubrication with fluorinated polyethers at cryogenic temperatures compared to superfined mineral oil
Dietrich, M. W.↗
SEARCH · Search NASA
Results for “ROLL”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
A statistical analysis of the roll rate of a launch vehicle under the influence of random fin misalinements
Launch vehicle under influence of random fin misalignments, predicting roll rate by statistical analysis
Madden, R. B.↗
Evaluation of otolith organ function by means of ocular counter-rolling measurements
Ocular counter-rolling as otolith organ function indicator
Miller, E. F., II↗
An exploratory study of the roll behavior of ablating cones
Cone roll dynamics-ablation patterns coupling in hypersonic wind tunnels
Mcdevitt, J. B.↗
Roll function in a flight simulator
Method introduces roll into the flying-spot scanner by modifying the scanning waveforms.
Brain, A. E.↗
The development, design and test of a 66 W/kg (30-W/lb) roll-up solar array
A program to develop a 250 square foot roll-up solar array with a power-to-weight ratio exceeding 30 watts per pound is described. The system design and fabrication of a full scale engineering development model are discussed. The system and development test program results are presented. Special test equipment and test procedures are included, together with comparisons of experimental and analytical results.
Hasbach, W. A.↗
Roll-modulated lifting entry optimization.
Equations of lifting entry are considered for fixed-angle-of-attack vehicular motion with path control for roll modulation of lift. Attention is directed to relocation and its consequences for the fixed-angle-of-attack atmospheric entry problem. Two reduced-order methods for working with the resulting system of equations are briefly examined. The methods are deemed to warrant further study.
Kelley, H. J.↗
Improved diffusion welding and roll welding of titanium alloys
Auto-vacuum cleaning technique was applied to titanium parts prior to welding. This provides oxide-free welding surfaces. Diffusion welding can be accomplished in as little as five minutes of hot pressing. Roll welding can be accomplished with only ten percent deformation.
Holko, K. H.↗
Carbide factor predicts rolling-element bearing fatigue life
Analysis was made to determine correlation between number and size of carbide particles and rolling-element fatigue. Correlation was established, and carbide factor was derived that can be used to predict fatigue life more effectively than such variables as heat treatment, chemical composition, and hardening mechanism.
Chevalier, J. L.↗
Analysis of electrical contact occurrences between rolling surface with application to elastohydrodynamic lubrication
A mathematical model enabling the relation of electrical contact occurrences between rolling surfaces to the mean thickness of an elastohydrodynamic lubricant film is discussed. A previous development by other authors is shown to contain an error invalidating their results. Some potentially useful approximations are developed for the case when the lubricant film is large with respect to the surface roughness. Complete solutions that are valid for all film thicknesses are not yet available.
Sidik, S. M.↗
On the inviscid rolled-up structure of lift generated vortices
A simple form is presented of the relationships for the inviscid, fully developed structure of lift-generated vortices behind aircraft wings. The method is then extended to arbitrary span-load distributions by inferring guidelines for the selection of rollup centers for the vortex sheet, along with rules for calculating the fully developed structure of the resulting multiple vortices. These techniques yield realistic estimates of the rolled-up structure of vortices produced by a wider variety of span-load distributions than possible with the original form of the theory.
Rossow, V. J.↗
Design and development of LH2 cooled rolling element radial bearings for the NERVA engine turbopump. Volume 3: Phase 2: Tests on build-ups 16, 17, and 18 at NRDS, Jackass Flats, Nevada, December 1971 - March 1972
The use of liquid hydrogen to cool the rolling element radial bearings in the nuclear engine for rocket vehicles is discussed. The fifteen hour service life goal was obtained during the tests. The increase in bearing life was also considered to be produced by: (1) improvements in bearing material, (2) bearing retainer configuration and manufacturing changes, and (3) better control of operating parameters.
Accinelli, J. B.↗
Low mass rolling element for bearings
Low mass rolling elements for bearings having a high fatigue strength and high resistance to flexure fatigue are reported. The elements have a lightweight core with a hollow center or is made of a low density material. The core is plated to provide a hard surface.
Parker, R. J.↗
High speed hybrid bearing comprising a fluid bearing and a rolling bearing convected in series
A description is given of an antifriction bearing and a process by which its fatigue life may be extended. The method involves a rotating shaft supported by a fluid bearing and a rolling element bearing coupled in series. Each bearing turns at a fraction of the rotational speed of the shaft. The fluid bearing is preferably conical, thereby providing thrust and radial load support in a single bearing structure.
Anderson, W. J.↗
Theoretical study of lift generated vortex sheets designed to avoid roll up
The random motions of the vortex elements behind a wing that sheds a disturbed, translating array of vortices are analyzed. The analysis indicates that the wake would diffuse and decay rapidly when viscosity is present and would produce small rolling moments on encountering aircraft. It was found that comparable results could also be achieved with an array consisting of vortices that are equal in magnitude but which alternate in sign. This observation indicates that random motion can probably be achieved with a variety of stepped loadings.
Rossow, V. J.↗
RUSAP: A computer program for the calculation of Roll-Up Solar Array Performance characteristics
RUSAP is a FORTRAN 4 computer program designed to determine the performance characteristics (power-to-weight ratio, blanket tension, structural member section dimensions, and resonant frequencies) of large-area, roll-up solar arrays of the single-boom, tensioned-substrate design. The program includes the determination of the size and weight of the base structure supporting the boom and blanket and the determination of the blanket tension and deployable boom stiffness needed to achieve the minimum-weight design for a specified frequency for the first mode of vibration. A complete listing of the program, a description of the theoretical background, and all information necessary to use the program are provided.
Ross, R. G., Jr.↗
Production of hollow components for rolling element bearings by diffusion welding
A hollow rolling element for a bearing is fabricated by diffusion welding hollow shells together. The hollow shell halves are joined by faying surfaces and diffusion welding.
Moore, T. J.↗
Rolling-element bearings: A review of the state of the art
Some of the research conducted which has brought rolling-element technology to its present state is discussed. Areas touched upon are material effects, processing variables, operating variables, design optimization, lubricant effects and lubrication methods. Finally, problem areas are discussed in relation to the present state-of-the-art and anticipated requirements.
Anderson, W. J.↗