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At least 217 records · Page 12

Internal capillary insulation for cryogenic tanks

Capillary-type insulation was devised for installation on inside of liquid methane fuel tanks for future aircraft. Insulation consists of honeycomb core of fiberglass cloth impregnated with polyimide resin which is bonded onto metal tank wall using polyimide adhesive. Capillary holes in each honeycomb cell admit methane which provides static pressure in cell.

Mcgrew, J. L.↗

Evaluation of epoxy systems for use in SBASI

The purpose of the test program was to evaluate the performance of different epoxy systems as replacements for existing epoxy systems in the SBASI. The three areas of investigation were the connector shell potting, the epoxy tape under the charge cup, and the epoxy impregnated fiberglass over the output charge. Factors considered, in addition to performance, were availability, shelf life, pot life, and effect on producibility and cost.

Coultas, T. J.↗

Composite overwrapped metallic tanks

Work is reported for fabricating and testing the fiberglass overwrapped titanium pressure vessel for cryogenic service. Difficulties encountered in the tank liner fabrication phase involved explosive forming, vacuum annealing, chemical milling and electron beam welding. While each of these processes and the nondestructive test methods employed are normally considered to be individually reliable, the combination of poor material together with fabrication and development reversals prevented the full achievement of the desired end results. Eight tanks plus a prototype and tool proofing article were produced. Six of the vessels failed during the hydrostatic sizing operation. One of the remaining tanks was hydrostatically pressurized to burst and the other was pressurized repeatedly at 75 F from 100 psi to the operating pressure until failure occurred. As a result, it is not possible to draw firm conclusions as to the true value of the design concept due to the problems encountered in the program.

Caudill, C. L.↗

Manufacture and quality control of interconnecting wire hardnesses, Volume 1

A standard is presented for manufacture, installation, and quality control of eight types of interconnecting wire harnesses. The processes, process controls, and inspection and test requirements reflected are based on acknowledgment of harness design requirements, acknowledgment of harness installation requirements, identification of the various parts, materials, etc., utilized in harness manufacture, and formulation of a typical manufacturing flow diagram for identification of each manufacturing and quality control process, operation, inspection, and test. The document covers interconnecting wire harnesses defined in the design standard, including type 1, enclosed in fluorocarbon elastomer convolute, tubing; type 2, enclosed in TFE convolute tubing lines with fiberglass braid; type 3, enclosed in TFE convolute tubing; and type 5, combination of types 3 and 4. Knowledge gained through experience on the Saturn 5 program coupled with recent advances in techniques, materials, and processes was incorporated.

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Cryogenically formed prestressed composite fiber-metal structures for O2/N2 high pressure gas tanks.

Demonstration of high-structural-performance ARDEFORM cryoformed 301 stainless-steel glass-fiber-reinforced (GFR) vessels by room temperature tests of 13 1/2-in. diam spheres. Tests verified that the structural performance of ARDEFORM spherical GFR vessels not only exceeded that of all metal construction, but also bettered previous GFR experimental results by 50%. Achievement of essentially the full strength of fiberglass in a spherical wrap pattern was again verified. Significant weight advantages for this construction are projected for O2/N2 high-pressure gas tanks for Space Shuttle environmental control/life support system missions.

Gleich, D.↗

Performance of absorptive liners in the presence of spinning modes.

Results of free field measurements of the absorption coefficient of fiberglass, which indicate that the material has a high coefficient over a broad frequency range with little angular dependence. This material is also a very effective duct liner and attenuates spinning modes more rapidly than plane waves. The resonant absorber tested exhibits a strong angular and frequency dependence of the absorption coefficient, is only a moderately effective duct liner for spinning modes, and produces no measurable attenuation for plane waves.

Mcdaniel, O. H.↗

Evaluation of thermal insulation materials

Data was obtained on silicone-bonded fiberglass, isocyanurate foam, and two dozen other insulators. Materials were selected to withstand heat sterilization, outer space, and the Martian atmosphere. Significant environmental parameters were vibration, landing shock, and launch venting.

Wilbers, O. J.↗

Procedure for dispersing fiber bundles

Fiber bundles are dispersed and fibers are cleaned within enclosed container; therefore, safety clothing, masks, and eye protection are not required. Procedure also could be used wherever materials, such as fiberglass or insulation, require dispersion, fluffing, or cleaning. Process could be automated into continuous operation for handling large quantities of fiber.

Padilla, D.↗

Feasibility study of applying an advanced composite structure technique to the fabrication of helicopter rotor blades

The fabrication of helicopter rotary wings from composite materials is discussed. Two composite spar specimens consisting of compressively prestressed stainless steel liner over-wrapped with pretensioned fiberglass were constructed. High liner strength and toughness together with the prescribed prestresses and final sizing of the part are achieved by means of cryogenic stretch forming of the fiber wrapped composite spar at minus 320 F, followed by release of the forming pressure and warm up to room temperature. The prestresses are chosen to provide residual compression in the metal liner under operating loads.

Gleich, D.↗

Design and development of pressure and repressurization purge system for reusable space shuttle multilayer insulation system

The manufacturing tasks for the program included the fabrication and assembly of an epoxy fiberglass purge bag to encapsulate an insulated cryogenic propellant tank. Purge, repressurization and venting hardware were procured and installed on the purge bag assembly in preparation for performance testing. The fabrication and installation of the superfloc multilayer insulation (MLI) on the cryogenic tank was accomplished as part of a continuing program. An abstraction of the results of the MLI fabrication task is included to describe the complete fabrication requirements for a reusable cryogenic propellant space storage system.

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High temperature resistant composites from bismaleimide resin.

It is shown that bismaleimide/woven fiberglass composites molded at moderate pressures (100 psi) yield void-free laminates of good integrity. The strength of the laminates at room temperature compares favorably with epoxy/glass laminates; at 260 C, the laminates are far superior in oxidative aging to epoxy and silicon laminates. The synthesis, processing, and fabrication of a bismaleide polymer are discussed.

Gilwee, W. J.↗

Carbon microsphere-filled Pyrrone foams.

Syntactic foam formulations were prepared from mixtures of Pyrrone prepolymers and hollow carbon microspheres. Very low curing shrinkages were obtained for high volume loadings of microspheres. The resulting syntactic foams were found to be remarkably stable over a wide range in temperature. A technique was developed for the emplacement of these foam formulations in polyimide-fiberglass, titanium alloy and stainless steel honeycomb without sacrificing low curing shrinkage or thermal stability.

Kimmel, B. G.↗

A monkey metabolism pod for space-flight weightlessness studies.

The system described will permit quantitative physiological studies in adult monkeys, weighing from 8 to 14 kg, during future space flights. The system comprises a fiberglass pod containing a comfortable restraint couch for the animal. The pod is divided into upper and lower halves. When the monkey occupies the couch, a rubber belly-band forms a gas seal between the upper and lower portions of the animal. The upper-pod ventilating air stream is monitored for the partial pressures of oxygen, carbon dioxide, nitrogen, and water to permit continuous metabolic gas-exchange measurements for computation of metabolic energy expediture. The lower pod is lined with ashless filter paper for excreta collection.

Pace, N.↗

Preliminary results from dynamic model tests of an air cushion landing system.

Experimental study of the behavior of an air cushion landing system on 1:10 and 1:4-scale dynamic models of the CC-115 aircraft over a range of initial impact, on a smooth hard surface of fiberglass-coated plywood, on calm water, and on rough water with waves 5 ft high and 100 ft crest-to-crest wide. The performance was satisfactory with the 1:10 scale model on hard surfaces and calm water and was less certain, requiring more tests, on rough water, while substantial pitching oscillations were observed in tests on the 1:4 scale model.

Leland, T. J. W.↗

The use of paper honeycomb for prototype blade construction for small to medium-sized wind driven generators

Paper honeycomb is used for the construction of conventional, propeller-type, windmill blades. Using fairly simple techniques and conventional power tools, it is possible to shape both simple foils and more complex foils with or without tapered plan forms and with or without varying profiles. A block of honeycomb, in its compressed form, is mounted on a wedge and run through a bandsaw with the table at an appropriate tilt angle. It is the combination of the wedge angle and the table angle that gives the tapered planform and profile shape. Next the honeycomb is expanded on the shaft and jigged to give the desired angles of attack. With the honeycomb fixed in position, the blade is covered with a fine weave fiberglass cloth. Any surface quality can then be achieved with filling and sanding.

Meyer, H.↗

Design, fabrication, and test of lightweight shell structure

A cylindrical shell skirt structure was subjected to a design and analysis study using a wide variety of structural materials and concepts. The design loading, axial compression, and torsion is representative of that expected on a typical space tug skirt section. Structural concepts evaluated included honeycomb sandwich, truss, isogrid, and skin/stringer/frame. The materials considered included a wide variety of structural metals as well as glass, graphite, and boron-reinforced composites. Honeycomb sandwich with aluminum faceskins, honeycomb sandwich with graphite/epoxy faceskins, and aluminum truss with fiberglass meteoroid protection layers were the designs selected for further evaluation. Procurement of materials required for fabrication is reported and the structural test plan and fabrication drawings are included. Construction of the graphite/epoxy faceskins, chem mill of the aluminum faceskins, chem mill of aluminum truss components, and fabrication of the graphite/epoxy honeycomb sandwich development panel is also reported.

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