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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 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Design and fabrication of a flexible tunnel for Sortie Laboratory

A program was conducted to update a prototype design and to fabricate a flexible tunnel for a space shuttle/spacelab interface structure. The significant changes in the prototype are as follows: (1) elimination of foam from bladder laminate to increase bladder flexibility, (2) heat treat pulley brackets, bolts, and hinge pin to 160,000 psi minimum tensile strength, and (3) reduction of the meteoroid barrier from 0.5 inch to 0.375 inch. The thermal blanket installation study resulted in developing a method of installation by properly folding the various layers so that a uniform thickness could be maintained under the clamps. A single-lobe mockup was fabricated and cycled open and closed several times with no apparent damage to the blanket.

Source record↗
NASA NTRS1975

Boron/aluminum skins for the DC-10 aft pylon

Boron/aluminum pylon boat tail skins were designed and fabricated and installed on the DC-10 aircraft for a 5-year flight service demonstration test. Inspection and tests of the exposed skins will establish the ability of the boron/aluminum composite to withstand long time flight service conditions, which include exposure to high temperatures, sonic fatigue, and flutter. The results of a preliminary testing program yield room temperature and elevated temperature data on the tension, compression, in-plane shear, interlaminar shear, bolt bearing, and tension fatigue properties of the boron/aluminum laminates. Present technology was used in the fabrication of the skins. Although maximum weight saving was not sought, weight of the constant thickness boron/aluminum skin is 26% less than the chemically milled titanium skin.

Elliott, S. Y.↗
NASA NTRS1974

SEASAT study documentation

The proposed spacecraft consists of a bus module, containing all subsystems required for support of the sensors, and a payload module containing all of the sensor equipment. The two modules are bolted together to form the spacecraft, and electrical interfaces are accomplished via mated connectors at the interface plane. This approach permits independent parallel assembly and test operations on each module up until mating for final spacecraft integration and test operations. Proposed program schedules recognize the need to refine sensor/spacecraft interfaces prior to proceeding with procurement, reflect the lead times estimated by suppliers for delivery of equipment, reflect a comprehensive test program, and provide flexibility for unanticipated problems. The spacecraft systems are described in detail along with aerospace ground equipment, ground handling equipment, the launch vehicle, imaging radar incorporation, and systems tests.

Source record↗
NASA NTRS1975

Assessment of NDE reliability data

Twenty sets of relevant nondestructive test (NDT) reliability data were identified, collected, compiled, and categorized. A criterion for the selection of data for statistical analysis considerations was formulated, and a model to grade the quality and validity of the data sets was developed. Data input formats, which record the pertinent parameters of the defect/specimen and inspection procedures, were formulated for each NDE method. A comprehensive computer program was written and debugged to calculate the probability of flaw detection at several confidence limits by the binomial distribution. This program also selects the desired data sets for pooling and tests the statistical pooling criteria before calculating the composite detection reliability. An example of the calculated reliability of crack detection in bolt holes by an automatic eddy current method is presented.

Yee, B. G. W.↗
NASA NTRS1975

Design and fabrication of composite wing panels containing a production splice

Bolted specimens representative of both upper and lower wing surface splices of a transport aircraft were designed and manufactured for static and random load tension and compression fatigue testing including ground-air-ground load reversals. The specimens were fabricated with graphite-epoxy composite material. Multiple tests were conducted at various load levels and the results were used as input to a statistical wearout model. The statically designed specimens performed very well under highly magnified fatigue loadings. Two large panels, one tension and compression, were fabricated for testing by NASA-LRC.

Reed, D. L.↗
NASA NTRS1975

Studies of finite element analysis of composite material structures

Research in the area of finite element analysis is summarized. Topics discussed include finite element analysis of a picture frame shear test, BANSAP (a bandwidth reduction program for SAP IV), FEMESH (a finite element mesh generation program based on isoparametric zones), and finite element analysis of a composite bolted joint specimens.

Douglas, D. O.↗
NASA NTRS1976

Large-diameter fasteners of CRES alloy

Double-hex bolthead allows bolts of high strength corrosion-resistant steel (CRES) to be made in diameters up to 1-1/4 in. Design allows 12-point tension heads to be cold formed to retain required minimum tensile strength of 220,000 psi and to retain high fracture strength.

Charles, J. F.↗
NASA NTRS1977

Dynamic load attenuator

Instrument consists of special bolt head that cuts material from splined washer. Required shear and tensile forces absorb kinetic energy. Cut-away material is retained by shearing action, making device useful where production of loose metal particles is not acceptable.

Crum, P. N.↗
NASA NTRS1977

Improved bonding of honeycomb panels

Technique, using angular metal braces bonded onto panels, lowers construction costs. Technique improves overall structural strength, decreases assembly time, and avoids wear points created by bolts and rivets.

Sobkiewicz, S. A.↗
NASA NTRS1975

Design definition study of NASA/Navy lift/cruise fan V/STOL aircraft. Volume 1: Summary report of Navy multimission aircraft

This report presents results of a study by the Rockwell International Corporation for the NASA Ames Research Center and the Naval Air Systems Command of promising Navy lift-cruise fan V/STOL aircraft for the 1980-1985 time period. The purpose of the study was to identify the likely technical and operating characteristics and technology requirements for the ultimate development of this type aircraft. The study focused on identifying aircraft individually optimized to perform the anti-submarine warfare, carrier onboard delivery, combat search and rescue, surveillance and surface attack missions, and a multi-purpose aircraft concept capable of performing all five missions at minimum total program cost. The configuration features the use of two 1.3 fan pressure ratio, single stage lift-cruise fans and three current design J97 gas generators with a high mounted high aspect ratio wing with winglets. The design missions can be performed at takeoff weights ranging from approximately 32,000 to 39,000 pounds. Top speed is 0.80 Mach number at sea level and 0.885 at altitude, Advanced composite structural technology and advanced subsystem concepts are employed. One basic fuselage design, with alternate bolt-in floor structures, meets all the mission requirements.

Robert L Cavage↗
NASA NTRS1977

Fluid-connector selection

Usefulness of dynamic programming for systems design is illustrated by study on selection of separable bolted connectors for aerospace applications. Report should be of specific interest to those considering other dynamic programming applications in fields such as construction of refineries, chemical plants, and electronics.

Prasthofer, W. P.↗
NASA NTRS1977

Mass-balanced portable stairway

Multilevel upwardly expandable scaffold accommodates up to four workers. Device consists of base, tower sections, and gangway which are stacked to required height and bolted together for vertical stability. Hollow central rectangular column affords convenient place to store tools and equipment. Maintenance requirements reduced through elimination of hydraulic devices to lift structure.

Kerley, J. J., Jr.↗
NASA NTRS1978

Cable-clamp installation tool

Tiny vise simplifies installation of cable clamps in confined spaces. As thumbscrew is tightened, ears of clamps are forced together, and bolt passes through all lugs and into hole in stationary jaw.

Noel, M. B.↗
NASA NTRS1977

Packaging of a large capacity magnetic bubble domain spacecraft recorder

A Solid State Spacecraft Data Recorder (SSDR), based on bubble domain technology, having a storage capacity of 10 to the 8th power bits, was designed and is being tested. The recorder consists of two memory modules each having 32 cells, each cell containing sixteen 100 kilobit serial bubble memory chips. The memory modules are interconnected to a Drive and Control Unit (DCU) module containing four microprocessors, 500 integrated circuits, a RAM core memory and two PROM's. The two memory modules and DCU are housed in individual machined aluminum frames, are stacked in brick fashion and through bolted to a base plate assembly which also houses the power supply.

Becker, F. J.↗
NASA NTRS1977

Study to investigate design, fabrication and test of low cost concepts for large hybrid composite helicopter fuselage, phase 2

The development of a frame/stringer/skin fabrication technique for composite airframe construction was studied as a low cost approach to the manufacturer of larger helicopter airframe components. A center cabin aluminum airframe section of the Sikorsky CH-53D, was selected for evaluation as a composite structure. The design, as developed, is composed of a woven KEVLAR R-49/epoxy skin and graphite/epoxy frames and stringers. The single cure concept is made possible by the utilization of pre-molded foam cores, over which the graphite/epoxy pre-impregnated frame and stringer reinforcements are positioned. Bolted composite channel sections were selected as the optimum joint construction. The applicability of the single cure concept to larger realistic curved airframe sections, and the durability of the composite structure in a realistic spectrum fatigue environment, was described.

Adams, K. M.↗
NASA NTRS1978

Effects of fabrication and joining processes on compressive strength of boron/aluminum and borsic/aluminum structural panels

Processes for forming and joining boron/aluminum and borsic/aluminum to themselves and to titanium alloys were studied. Composite skin and titanium skin panels were joined to composite stringers by high strength bolts, by spotwelding, by diffusion bonding, by adhesive bonding, or by brazing. The effects of the fabrication and joining processes on panel compressive strengths were discussed. Predicted buckling loads were compared with experimental data.

Royster, D. M.↗
NASA NTRS1978

Influence of fretting on flexural fatigue of 304 stainless steel and mild steel

Fretting fatigue experiments conducted on 304 stainless steel using a flexural fatigue test arrangement with bolted on fretting pads demonstrated that fatigue life is reduced by at least a factor of 10 in the 265 to 334 MPa (38,500 - to 48,500 psi) nominal flexural fatigue stress range. In addition, experiments in which the fretting pads were removed after selected numbers of cycles, followed by continued flexural fatigue without fretting show that continued fretting beyond 50,000 cycles does not significantly further reduce fatigue life of 304 stainless steel at 317 MPa (46,000 psi). Microscopic examination of the fretted contact areas revealed fracture initiation sites as well as numerous cracks that did not propagate to failure. Flexural fretting fatigue experiments performed on mild steel showed an insensitivity of fatigue life to the incidence of fretting under flexural stress conditions of from 162 to 217 MPa (23,500 to 31,500 psi).

Bill, R. C.↗
NASA NTRS1978

Slicing of silicon into sheet material. Silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

Fabrication of a prototype large capacity multiple blade slurry saw is considered. Design of the bladehead which will tension up to 1000 blades, and cut a 45 cm long silicon ingot as large as 12 cm in diameter is given. The large blade tensioning force of 270,000 kg is applied through two bolts acting on a pair of scissor toggles, significantly reducing operator set-up time. Tests with an upside-down cutting technique resulted in 100% wafering yields and the highest wafer accuracy yet experienced with MS slicing. Variations in oil and abrasives resulted only in degraded slicing results. A technique of continuous abrasive slurry separation to remove silicon debris is described.

Holden, S. C.↗