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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 1,045 records · Page 58
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Friction welding.

Results of an exploratory study of the structure and properties of friction welds in Udimet 700 (U-700) and TD-nickel (TD-Ni) bar materials, as well as dissimilar U-700/TD-Ni friction welds. Butt welds were prepared by friction welding 12.7-mm-diam U-700 bars and TD-Ni bars. Specimens for elevated temperature tensile and stress rupture testing were machined after a postweld heat treatment. Friction welding of U-700 shows great potential because the welds were found to be as strong as the parent metal in stress rupture and tensile tests at 760 and 980 C. In addition, the weld line was not detectable by metallographic examination after postheating. Friction welds in TD-Ni or between U-700 and TD-Ni were extremely weak at elevated temperatures. The TD-Ni friction welds could support only 9% as much stress as the base metal for 10-hour stress rupture life at 1090 C. The U-700/TD-Ni weld could sustain only 15% as much stress as the TD-Ni parent metal for a 10-hour stress rupture life at 930 C. Thus friction welding is not a suitable joining method for obtaining high-strength TD-Ni or U-700/TD-Ni weldments.

Moore, T. J.↗
NASA NTRS1971

Development of a full-length external-fuel thermionic converter for in-pile testing.

Description of an external-fuel thermionic converter which utilizes a thoriated-tungsten fuel-emitter body. Performance in out-of-pile tests was comparable to that of an arc-cast tungsten emitter body, with 400-eW output power (about 5 W/sq cm) at 10.8% efficiency. Maximum fuel clad temperature averaged from 1650 to 1700 C during the 300-hour test. This converter has been processed for in-pile testing. The various processing steps, including the installation of six emitter thermocouples, encapsulation in the secondary container, and joining to the fission-gas collection system, are described in detail. In addition to the converter assembly, a doubly contained fission gas collection assembly with radiation-hardened differential pressure transducers was fabricated. The experiment support plate required for the in-pile test, containing electrically insulated instrumentation feedthroughs and coolant line feedthroughs to the vacuum test chamber, was also fabricated.

Schock, A.↗
NASA NTRS1972

Analytic models of electron impact excitation cross sections.

A number of analytic forms are presented which have been used to represent electron impact excitation cross sections all the way from threshold to the high energy domain where they join approximately to the results of the Born-Bethe approximation. Techniques for estimating the parameters in these analytic forms are described in detail so that the reader can update his own parameter set when new experimental information becomes available. A short collection of parameters for excitations to key states of N2, O2 and O is given along with references to sources where more complete sets are available. The importance of analytic models as a means of communication to aeronomical users of cross sections is discussed.

Green, A. E. S.↗
NASA NTRS1973

Materials data handbook on titanium 6Al-4V

Handbook has been prepared which describes latest property information on titanium 6Al-4V. Scope of information presented includes physical- and mechanical-property data at cryogenic, ambient, and elevated temperatures, supplemented with useful information in such areas as material procurement,metallurgy of alloy, corrosion, environmental effects, fabrication, and joining technology.

Muraca, R. F.↗
NASA NTRS1973

Materials data handbook on Inconel Alloy 718

Handbook is divided into twelve chapters. Scope of information presented includes physical- and mechanical-property data at cryogenic, ambient, and elevated temperatures. This is supplemented with useful information in such areas as material procurement, metallurgy of alloy, corrosion, environmental effect, fabrication, and joining techniques. Design data are presented, as available.

Muraca, R. F.↗
NASA NTRS1974

RF shielded connectors

Gap, where cable joins connector housing, is shielded effectively by composite RF shielding made from suitable potting resin material (fumed silica, thixotropic prepolymer composition), conductive coating (silver-filled, flexible, polyurethane resin), and protective jacket (wax coated housing formed around another wax form having contours shaped to match configuration).

Fisher, A.↗
NASA NTRS1972

High temperature (1200 C) ceramic-to-metal seal development

Two phases have been completed, of a program whose ultimate objective is the development of an alkali metal resistant, thermal shock resistant, leak-tight, and neutron radiation resistant ceramic-to-metal seal capable of operation at 1200 C for three to five years. The first phase involved the screening of platinum-base, vanadium-base and vanadium-niobium base brazes for the joining of Cb-1Zr or T-111 alloys to high purity alumina. The second phase involved studies of the performance of sealed capsule samples during 5000-hour aging tests at 800, 1000, and 1200 C in high vacuum. Sealed capsules which were made using pure vanadium braze, and were brazed at 1850 C for one minute, survived 64 thermal cycles to 1200 C at the heating/cooling rate of 100 C/minute. Vanadium braze samples survived 5000-hour aging tests at 800, 1000, and 1200 C. One thermally cycled sample survived a subsequent 5000-hour aging period at 1000 C, but another, at 1200 C, did not survive. It was concluded that a pure vanadium braze used to bond high purity alumina to Cb-1Zr alloy is the best of the systems studied, but that additional studies must be performed to establish its service temperature limitations for the desired three to five years' service.

Mckisson, R. L.↗
NASA NTRS1972

Design and development of polyphenylene oxide foam as a reusable internal insulation for LH2 tanks, phase 2

PPO form was tested for mechanical strength, for the effects of 100 thermal cycles from 450 K (359 F) to 21 K (-423 F) and for gas flow resistance characteristics. PPO foam panels were investigated for density variations, methods for joining panels were studied and panel joint thermal test specimens were fabricated. The range of foam panel thickness under investigation was extended to include 7 mm (0.3 in) and 70 mm (2.8 in) panels which also were tested for thermal performance.

Source record↗
NASA NTRS1973

Self-recording portable soil penetrometer

A lightweight portable penetrometer for testing soil characteristics is described. The penetrometer is composed of a handle, data recording, and probe components detachably joined together. The data recording component has an easily removed recording drum which rotates according to the downward force applied on the handle, and a stylus means for marking the drum along its height according to the penetration depth of probe into the soil.

Costes, N. C.↗
NASA NTRS1973

Study of design and control of remote manipulators. Part 2: Vibration considerations in manipulator design

An investigation is reported involving a mathematical procedure using 4 x 4 transformation matrices for analyzing the vibrations of flexible manipulators. Previous studies with the procedure are summarized and the method is extended to include flexible joints as well as links, and to account for the effects of various power transmission schemes. A systematic study of the allocation of structural material and the placement of components such as motors and gearboxes was undertaken using the analytical tools developed. As one step in this direction the variables which relate the vibration parameters of the arm to the task and environment of the arm were isolated and nondimensionalized. The 4 x 4 transformation matrices were also used to develop analytical expressions for the terms of the complete 6 x 6 compliance matrix for the case of two flexible links joined by a rotating joint, flexible about its axis of rotation.

Book, W. J.↗
NASA NTRS1972

Lunar volcanism: Mare ridges and sinuous rilles, part P

Additional evidence of the volcanic origin of mare ridges and sinuous rilles is provided by near-terminator photography of the Herigonius Rille area (12 deg S 37 deg W) northeast of Gassendi Crater. A possible genetic relationship between ridges and rilles is illustrated. From the figure, the following relationships are evident. (1) The most prominent rille crosses several ridges without distortion, which indicates that the mare ridges did not form after the sinuous rilles. (2) The rilles could not have formed by flow up and over the ridges. (3) The rilles extend from their widest ends toward distinctly lower elevations, and the largest one branches both north and south from the vent area. Elevations are evident in stereographic views that clearly indicate the local slopes. (4) The wider end of each rille is marked by an elongate vent (?) near the summit of the mare ridge from which the rille appears to issue. (5) The two most prominent rilles join south of the vent area and continue southward for more than 130 km.

Young, R. A.↗
NASA NTRS1972

Development of welded metal bellows having minimum effective diameter change

A program of analysis, design, and fabrication was conducted to develop welded metal bellows having a minimum change in effective diameter for cryogenic turbomachinery face seal applications. Linear analysis of the principle types of bellows provided identification of concepts capable of meeting basic operation requirements. For the 6-inch (.152 m) mean diameter, 1.5-inch free length bellows studied, nonlinear analysis showed that opposed and nested toroidal bellows plates stiffened by means of alternating stiffener rings were capable of maintaining constant effective diameter within 0.3% and 0.1% respectively under the operating conditions of interest. Changes in effective diameter were due principally to bellows axial deflection with pressure differential having a lesser influence. Fabrication problems associated with joining the thin bellows plates to the relatively heavy stiffener rings were encountered and precluded assembly and testing of a bellows core. Fabrication problems are summarized and recommended fabrication methods for future effort are presented.

Henschel, J. K.↗
NASA NTRS1973

Computer program for the load and trajectory analysis of two DOF bodies connected by an elastic tether: Users manual

The derivation of the differential equations of motion of a 3 Degrees of Freedom body joined to a 3 Degrees of Freedom body by an elastic tether. The tether is represented by a spring and dashpot in parallel. A computer program which integrates the equations of motion is also described. Although the derivation of the equations of motions are for a general system, the computer program is written for defining loads in large boosters recovered by parachutes.

Doyle, G. R., Jr.↗
NASA NTRS1973

Restraint system for ergometer

A restraint system for securing a person to an ergometer while exercising under zero gravity conditions or while operating the ergometer in earth environment in a position other than the upright position. A padded, form-fitting body belt fits around the operator's waist and suspenders are attached to the body belt. The body belt is secured to the ergometer forwardly and rearwardly of the ergometer seat by adjustable belts joined to the body belt and releasably hooked to the ergometer frame.

Gause, R. L.↗
NASA NTRS1973

Pressurized panel

Large area pressurized meteoroid penetration detector panels with maximum inherent structural rigidity are provided. The panels measure directly the penetration rate in materials to be used in spacecraft. Panel structure include an interconnected cellular configuration in which the cells have spaced periphery welds and tufts in their centers. A spot weld is made at the center point joining the panels.

White, E. C.↗
NASA NTRS1973

Welding blades to rotors

A process is described to form T-joints between dissimilar thickness parts by magnetic force upset welding. This type of resistance welding is used to join compressor and turbine parts which thereby reduces the weight and cost of jet engines.

Hoklo, K. H.↗
NASA NTRS1973

Foot pedal operated fluid type exercising device

A foot pedal operated exercising device is reported that contains a dynamometer formed of a pair of cylinders each containing a piston. The pistons are linked to each other. The upper portions of the two cylinders are joined together by a common opening to provide a common fluid reservoir and each piston is provided with a one way check valve to maintain an adequate supply of working fluid. Fluid from the driven cylinder is transmitted to the other cylinder through separate constant force spring biased valves each valve takes the predominant portion of the pressure drop thereby providing a constant force hydraulic dynamometer. A device is provided to determine the amount of movement of piston travel.

Crum, G. W.↗