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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Improved fireman's compressed air breathing system pressure vessel development program

Prototype high pressure glass filament-wound, aluminum-lined pressurant vessels suitable for use in a fireman's compressed air breathing system were designed, fabricated, and acceptance tested in order to demonstrate the feasibility of producing such high performance, lightweight units. The 4000 psi tanks have a 60 standard cubic foot (SCF) air capacity, and have a 6.5 inch diamter, 19 inch length, 415 inch volume, weigh 13 pounds when empty, and contain 33 percent more air than the current 45 SCF (2250 psi) steel units. The current steel 60 SCF (3000 psi) tanks weigh approximately twice as much as the prototype when empty, and are 2 inches, or 10 percent shorter. The prototype units also have non-rusting aluminum interiors, which removes the hazard of corrosion, the need for internal coatings, and the possibility of rust particles clogging the breathing system.

King, H. A.↗
NASA NTRS1975

Variable-volume atomic storage vessel for hydrogen masers

Vessel, located in maser cavity, is made from cylindrical, convoluted flexible bellows which can be expanded or contracted along the cylinder axis vertically. Inner surface area remains constant with changing volume, permitting measurement of frequency deviations of excited atoms.

Peters, H. F.↗
NASA NTRS1974

Automated system for measurement, collection and processing of hydrometeorological data aboard scientific research vessels of the GUGMS (SIGMA-s)

A report is made on the automated system known as SIGMA-s for the measurement, collection, and processing of hydrometeorological data aboard scientific research vessels of the Hydrometeorological Service. The various components of the system and the interfacing between them are described, as well as the projects that the system is equipped to handle.

Borisenkov, Y. P.↗
NASA NTRS1975

An automated program for reinforcement requirements for openings in cylindrical pressure vessels

An automated interactive program for calculating the reinforcement requirements for openings in cylindrical pressure vessels subjected to internal pressure is described. The program is written for an electronic desk top calculator. The program calculates the required area of reinforcement for a given opening and compares this value with the area of reinforcement provided by a proposed design. All program steps, operating instructions, and example problems with input and sample output are documented.

Wilson, J. F.↗
NASA NTRS1975

Environmental crack-growth behavior of high strength pressure vessel alloys

Results of sustained-load environmental crack growth threshold tests performed on six spacecraft pressure vessel alloys are presented. The alloys were Inconel 718, 6Al-4V titanium, A-286 steel, AM-350 stainless steel, cryoformed AISI 301 stainless steel; and cryoformed AISI 304L steel. The test environments for the program were air, pressurized gases of hydrogen, oxygen, nitrogen, and carbon dioxide, and liquid environments of distilled water, sea water, nitrogen tetroxide, hydrazine, aerozine 50, monomethyl hydrazine, and hydrogen peroxide. Surface flaw type specimens were used with flaws located in both base metal and weld metal.

Forman, R. G.↗
NASA NTRS1976

Ultra-lightweight pressure vessels

Composite tanks fabricated from two metal spheres which are pressure welded and then overwrapped with plastic composite are 66 percent lighter than similar all-metal vessels. Overwrap minimizes shrapnel effects, shifts failure mode to that of cyclic leakage, and withstands minimum burst pressure.

Schmidt, W. W.↗
NASA NTRS1976

Proof test criteria for thin walled pressure vessels

Proof tests were conducted on surface-flaw pressure-vessel specimens of 2219-T87 aluminum base metal and weld metal at three different temperatures: 72, -320, and -423 F, and for three different metal sheet thicknesses: 0.125, 0.250, and 0.375 in. It was found that significant stable crack growth under increasing load can occur prior to failure. Initial flaw shapes and material conditions have a significant effect on the extent of crack growth. Stable crack growth initiates at a lower K sub Ii/K sub cr ratio and is more severe in weld metal specimens than in base metal specimens. Low aspect ratio flaws experience more growth in the depthwise direction than higher aspect ratio flaws. Proof testing assures that any first cycle failure will be by leakage, not by catastrophic failure.

Finger, R. W.↗
NASA NTRS1976

Ductile fracture of cylindrical vessels containing a large flaw

The fracture process in pressurized cylindrical vessels containing a relatively large flaw is considered. The flaw is assumed to be a part-through or through meridional crack. The flaw geometry, the yield behavior of the material, and the internal pressure are assumed to be such that in the neighborhood of the flaw the cylinder wall undergoes large-scale plastic deformations. Thus, the problem falls outside the range of applicability of conventional brittle fracture theories. To study the problem, plasticity considerations are introduced into the shell theory through the assumptions of fully-yielded net ligaments using a plastic strip model. Then a ductile fracture criterion is developed which is based on the concept of net ligament plastic instability. A limited verification is attempted by comparing the theoretical predictions with some existing experimental results.

Erdogan, F.↗
NASA NTRS1977

High-pressure cryogenic seals for pressure vessels

Problems associated with maintaining high pressures at cryogenic temperatures in pressure vessels are investigated. The goals were to identify the appropriate materials and design for a seal intended for cryogenic applications at pressures up to 4,080 bars (60,000 psi), and to examine the factors affecting the seal performance. The method employed and the apparatus used in a series of experimental seal system tests, and the test results are described in detail. It is concluded that the common seal designs and extrusion seal-ring materials such as Teflon, tin, and lead are not suitable. However, new seal systems developed using indium seal rings, brass or 304 stainless steel anvil rings, and two 0-rings of silicone rubber or Kel-F did prove suitable.

Buggle, A. E.↗
NASA NTRS1978

Predicting damage from exploding vessels

Workbook provides designer and safety engineer with best currently available technology for predicting damage and hazards from explosions of propellant tanks and bursts of pressure vessels.

Baker, W. E.↗
NASA NTRS1978

NASTRAN analysis of Tokamak vacuum vessel using interactive graphics

Isoparametric quadrilateral and triangular elements were used to represent the vacuum vessel shell structure. For toroidally symmetric loadings, MPCs were employed across model boundaries and rigid format 24 was invoked. Nonsymmetric loadings required the use of the cyclic symmetry analysis available with rigid format 49. NASTRAN served as an important analysis tool in the Tokamak design effort by providing a reliable means for assessing structural integrity. Interactive graphics were employed in the finite element model generation and in the post-processing of results. It was felt that model generation and checkout with interactive graphics reduced the modelling effort and debugging man-hours significantly.

Miller, A.↗
NASA NTRS1978

Common pressure vessel battery performance

Performance tests run on two common pressure vessel type nickel hydrogen batteries are described and the results presented. The study included: (1) charge retention tests, (2) synchronous eclipse season cycling tests, and (3) temperature differential tests.

Otzinger, B.↗
NASA NTRS1979

Proof test criteria for thin walled pressure vessels

A proof test criterion for assuring minimum service life requirements for aerospace pressure vessels is provided. The criteria proposed are based on the results of several experimental programs conducted on surface flaw specimens fabricated from 2219 aluminum base and weld metal. A description is presented of the stable crack growth behavior of surface flaws during loading. Conclusions derived from an experimental program are discussed. It is found that significant stable crack growth under increasing load can occur prior to failure. However, significant variability in results can be anticipated even when carefully controlled laboratory procedures are employed.

Finger, R. W.↗
NASA NTRS1979

Effect of gravitation stress and hypokinesia on blood vessels of the testicle

Rabbits were exposed to single maximum endurable stresses of cranio-caudal direction, hypokinesia for periods of one to eight weeks, and hypokinesia followed by gravitation stresses. The stresses caused dilatation of vessels, greater sinuosity, and occasional ruptures of the walls and extravasation. The greater part of the capillaries were dilated; the greatest part constricted. In hypokinesia there was an increasing atrophy of the testes. Significant results are reported.

Palazhchenko, E. F.↗
NASA NTRS1982

Measuring Cyclic-Stress Properties of Pressure Vessels

Simulated-service cycle differs from conventional proof-test cycle in that specimen is subjected to sine-wave variation of stress instead of prolonged steady stress. Simulated-service testing is performed at low and high temperatures as well as at room temperatures. (Flaws initiated by severe stresses of proof testing can later develop into leaks during service, thus effectively reducing useful service life.) Method may be useful for commercial thin-wall vessels.

Fiftal, C. F.↗