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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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Elastic, pressure-sensitive orifice is used to automatically regulate the rate of gas flow into bearings under varying loads. Formed of a molded elastomer, theses orifices increase the stability of gas bearings.
Resin casting of the aluminum master pattern forms a plastic mold for encapsulating a cable connector. An elastomer is injected into the mold and cured. The mold is disassembled leaving an elastomeric encapsulation around the connector.
A basic component of any ultrahigh-vacuum system is a seal capable of isolating a test chamber from its higher pressure surroundings. Two of the most common vacuum seals now in use are the elastomer O-ring seal and the metallic shear seal. The former has the problem of outgassing and gas permeation; the latter requires a large force per unit seal-length to maintain the sealing action. The search for a seal which would provide minimal virtual and real leak rates in a chamber, without requiring a large force to consummate the seal, led to investigation of a liquid-metal seal.
Flexible, high strength curtain made of fiber glass silicone elastomer laminate provides thermal shielding for equipment.
Pressure transducer is isolated from shock and vibration forces by a pressure-compensated shock mount. Silicone elastomer O-rings within the shock mount serve as shock and vibration-damping pads.
Several silazane intermediate compounds and polymers have been prepared which are potentially useful as high temperature coatings and elastomers. These silazane polymers exhibit stability in a temperature range of 300 to 400 degrees C.
Large metal ring seal prevents gas leakage in hydrogen, helium, or nitrogen storage bottles at pressures up to 5,000 psi. The grooved ring seal which contains elastomer O-rings is installed between the mating faces of the access cover and the storage bottle.
Leakage at static seals is a problem common to both NASA and industry. The subject of an intensive investigation has been the establishing of design criteria for reliable, low-weight, leak-tight fluid connectors. The problem has been broken into areas of investigation: the structure which supports the actual seal and the seal itself. A Separable Connector Design Handbook has been written to direct designers' efforts toward the optimum connector design for a given purpose. Included in this paper is a brief discussion of the topics covered in the Handbook, notable flanged connector design, threaded connector design, pressure energized seal design, leakage measurement techniques, and a catalog of current satisfactory seal configurations. Also included in this paper is a discussion of the principles of sealing, including the uses and characteristics of elastomers, plastics, and metals. The load-leakage characteristics of seals, the effect of internal pressure, the effect of surface finish on the leakage rate, the mode of material deformation under load, and the advantages of various seal configurations are discussed.
Polymers containing silicon-nitrogen bonds as elastomers with high thermal stability for aerospace applications
Self-sealing closure enables small amounts of specific biochemical solutions to be withdrawn from or added to containers in inaccessible or small spaces. It uses a self-sealing septum of a silicone elastomer through which a hypodermic needle can be inserted.
Failure criteria for viscoelastic materials, crack propagation measurements, and elastomer foam degradation
Hypervelocity heat protection, surface heat shielding, and internal temperature rise of Teflon, phenolic nylon, epoxy resin in glass honeycomb, and silicone elastomer
Space environmental effects on elastomers and metallic materials
In situ vacuum testing requirement for valid measurement of vacuum induced changes in mechanical and thermal properties of various filled elastomers
Two new polyethers, poly /hexafluoropentamethylene tetrafluoro-p-phenylene ether/ and a completely hydroxyl-terminated polyether, is prepared by reactions of hexafluorobenzene with hexafluoropentanediol. The polyethers can be prepared as low molecular weight oils, as intermediate molecular weight waxes, or as high molecular weight elastomers.
Mechanical properties, morphology, and relaxation processes in elastomers and crystalline polymers
In situ vacuum testing requirement for valid measurement of vacuum induced changes in mechanical and thermal properties of various filled elastomers
Adhesives, coatings, coated fabrics, elastomers, encapsulants, films, hardware and structural materials, and tapes are tested in a series of physical, mechanical, and electrical tests. Material properties are measured before and after exposure to the three environments.