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Metal Fatigue Wiki dumped with WikiTeam tools.
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Metal Fatigue Wiki dumped with WikiTeam tools.
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149
149
Jun 13, 2011
06/11
by
Chamis, Christos C.; Minnetyan, Levo
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A simulation of corrosive management on polymer composites durability is presented. The corrosive environment is assumed to manage the polymer composite degradation on a ply-by-ply basis. The degradation is correlated with a measured Ph factor and is represented by voids, temperature, and moisture which vary parabolically for voids and linearly for temperature and moisture through the laminate thickness. The simulation is performed by a computational composite mechanics computer code which...
Topics: COPPER ALLOYS, FABRICATION, METAL FATIGUE, CREEP STRENGTH, ROCKET ENGINES, THERMAL CONDUCTIVITY
The CD that came with PC Gamer in April 2000. (US Edition) Demo's Included: Soldier of Fortune Thief II Test Drive 6 Link LS 2000 Metal Fatigue Command & Conquer: Tiberian Sun Majesty ISO file can be found here: https://archive.org/download/pcgamer-coverdisc-2000-04
Topics: pcgamer, demos, soldier of fortune, thief II, majesty, metal fatigue, pc gamer
183
183
Jul 12, 2010
07/10
by
Kern, R
texts
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Innovation and reliability in hyperfine frequency standards and clock systems are discussed. Hyperfine standards are defined as those precision frequency sources and clocks which use a hyperfine atomic transition for frequency control and which have realized significant commercial production and acceptance (cesium, hydrogen, and rubidium atoms). References to other systems such as thallium and ammonia are excluded since these atomic standards have not been commercially exploited in this country.
Topics: EXPANSION, LAMINATES, METAL FATIGUE, METAL MATRIX COMPOSITES, THERMAL STRESSES, POWDER METALLURGY,...
220
220
Jun 21, 2010
06/10
by
Frohlich, H.; Kreil, W.; Schweizer, G.; Stopfkuchen, K
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eye 220
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Dynamic model for study of pilot performance in vertical takeoff and landing and other types of aircraft
Topics: ADSORPTION, MINERAL OILS, METAL FATIGUE, PLASTIC FLOW, RUPTURING, SURFACTANTS, BRITTLENESS,...
211
211
May 31, 2011
05/11
by
Hervol, David; Mason, Lee; Birchenough, Arthu
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This paper presents experimental test results from operation of a 2 kWe Brayton power conversion unit. The Brayton converter was developed for a solar dynamic power system flight experiment planned for the Mir Space Station in 1997. The flight experiment was cancelled, but the converter was tested at Glenn Research Center as part of the Solar Dynamic Ground Test Demonstration system which included a solar concentrator, heat receiver, and space radiator. In preparation for the current testing,...
Topics: ALUMINUM ALLOYS, CRACK PROPAGATION, METAL FATIGUE, POWDER METALLURGY, CRACK TIPS, CREEP PROPERTIES,...
720
720
Jul 12, 2010
07/10
by
Cuddihy, E. F.; Coulbert, C. D.; Liang, R. H.; Gupta, A.; Willis, P.; Baum, B
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Terrestrial photovoltaic modules must undergo substantial reductions in cost in order to become economically attractive as practical devices for large scale production of electricity. Part of the cost reductions must be realized by the encapsulation materials that are used to package, protect, and support the solar cells, electrical interconnects, and other ancillary components. As many of the encapsulation materials are polymeric, cost reductions necessitate the use of low cost polymers. The...
Topics: EPOXY RESINS, LAMINATES, TURBINE BLADES, CORROSION, METAL FATIGUE, PLYWOOD, STRESS CONCENTRATION,...
298
298
Jun 21, 2010
06/10
by
Prelewicz, D. A
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eye 298
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Disturbance torque effects on cruise mode operations of Mariner 4 and Mariner 5
Topics: ADSORPTIVITY, METAL FATIGUE, PHYSICAL PROPERTIES, STEELS, CRYSTAL STRUCTURE, MECHANICAL PROPERTIES,...
310
310
Jun 1, 2011
06/11
by
vonKoenig, M.; Burrows, J. P.; Chipperfield, M. P.; Jackman, C. H.; Kallenrode, M.-B.; Kuenzi, K. F.; Quack, M
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The energy deposition in the mesosphere and stratosphere during large extraterrestrial charged particle precipitation events has been known for some time to contribute to ozone losses due to the formation of potential ozone destroying species like NO(sub x), and HO(sub x). These impacts have been measured and can be reproduced with chemistry models fairly well. In the recent past, however, even the impact of the largest solar proton events on the total amount of ozone has been small compared to...
Topics: FATIGUE TESTS, FATIGUE LIFE, DYNAMOMETERS, SIMULATION, CRACK INITIATION, CORROSION, STRESS...
Avco Specialty Materials' Chartek III fireproofing provides longterm fire protection for structural steel in high risk industrial applications such as structural conduits, pipes and valves of offshore platforms, and storage tanks used in hydrocarbon processing industry. In the presence of fire, Chartek III fire-proofing provides two kinds of protection. One of them is ablation, technique used on Apollo involving dissipation of heat by burnoff. The other is called intumescence or swelling. Heat...
Topics: NASA Technical Reports Server (NTRS), FIREPROOFING, STEEL STRUCTURES, PIPES (TUBES), ABLATION, FIRE...
391
391
Jun 21, 2010
06/10
by
Phillips, W. P
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eye 391
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Calculated aircraft stopping distances based on test results
Topics: FORGING, METAL FATIGUE, MICROSTRUCTURE, FRACTURE STRENGTH, LOAD TESTS, STRINGERS, TITANIUM ALLOYS,...
Criteria and recommended practices for preventing stress-corrosion cracking from impairing the structural integrity and flightworthiness of space vehicles are presented. The important variables affecting stress-corrosion cracking are considered to be the environment, including time and temperature; metal composition, and structure; and sustained tensile stress. For designing spacecraft structures that are free of stress-corrosion cracking for the service life of the vehicle the following rules...
Topics: NASA Technical Reports Server (NTRS), CRACKING (FRACTURING), METAL FATIGUE, SPACECRAFT STRUCTURES,...
742
742
Jul 6, 2010
07/10
by
Davis, C. E., Jr.; Jahn, N. P
texts
eye 742
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No Abstract Available
Topics: COPPER ALLOYS, ZIRCONIUM ALLOYS, FATIGUE TESTS, METAL FATIGUE, TENSILE PROPERTIES, TENSILE TESTS,...
Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground SISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620...
Topics: NASA Technical Reports Server (NTRS), GEARS, METAL FATIGUE, POWDER METALLURGY, STEELS, STRUCTURAL...
This presentation is about the development of advanced copper alloys with high thermal conductivity, good creep strength, and adequate fatigue strength for rocket engine applications. It also focuses on the commercial availability of the advanced alloy-GRCop-84 developed at NASA-GRC. The presentation's conclusions are that GRCop-84 has equivalent or better isothermal fatigue lives compared to other commercially available copper alloys, that GRCop-84 can be fabricated in various forms with...
Topics: NASA Technical Reports Server (NTRS), COPPER ALLOYS, FABRICATION, METAL FATIGUE, CREEP STRENGTH,...
The mode 1 stress intensity factors were computed for round compact specimens by the boundary collocation method. Results are presented for ratios A sub T/R sub 0 in the range 0.3 to 0.8, where A sub t is the distance from the specimen center to the crack tip for a specimen of diameter 2R sub 0.
Topics: NASA Technical Reports Server (NTRS), FRACTURE STRENGTH, METAL WORKING, SPHERES, STRESS RATIO,...
201
201
Jul 26, 2010
07/10
by
Rollbuhler, R. James; Kinney, George R.; Leopold, Lorenz, C
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No Abstract Available
Topics: ALUMINUM ALLOYS, STAINLESS STEELS, STRESS CONCENTRATION, CREEP TESTS, CYCLIC LOADS, METAL JOINTS,...
477
477
Sep 20, 2010
09/10
by
Barnes, Jeffrey R
texts
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A broad range of phenomena were addressed by the study including the following: (1) polar warming; (2) forced stationary waves; (3) gravity waves; (4) transient baroclinic eddies; and (5) radiative-dynamical instabilities. A variety of numerical models have been employed in these studies, as well as analytical approaches. Some of the most significant results from this work are very briefly summarized.
Topics: ACOUSTIC EMISSION, CRACKS, RESONANT FREQUENCIES, ACOUSTIC MEASUREMENT, CRACK GEOMETRY, CRACK...
The design, development, and performance characteristics of two roll ring configurations - a roll ring being a device used in transferring electrical energy across a continuously rotating or oscillating interface through one or more flexible rolling contacts, or flexures are described. Emphasis is placed on the design problems and solutions encountered during development in the areas of flexure fatigue, contact electroplating, electrical noise, and control of interface geometry. Also, the...
Topics: NASA Technical Reports Server (NTRS), ELECTRIC CONTACTS, RING STRUCTURES, ROLLERS, ROTATING BODIES,...
When rapid oscillation of blanket wearing looms at Chatham Manufacturing Company caused significant metal fatigue, the company turned to NC/STRC for a NASA data bank computer search. The search pinpointed tensile stress, and suggested a built-in residual compressive stress as a solution. "Shot peening," bombarding a part with a high velocity stream of very small shot to pound and compress the part's surface, was found to be the only practical method for creating compressive stress....
Topics: NASA Technical Reports Server (NTRS), FABRICS, MANUFACTURING, COMPRESSION LOADS, METAL FATIGUE,...
170
170
Jul 26, 2010
07/10
by
Chung, C. L.; Desa, S.; Desilva, C. W
texts
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One of the problems associated with redundant manipulators which were proposed for space applications is that the reactions transmitted to the base of the manipulator as a result of the motion of the manipulator will cause undesirable effects on the dynamic behavior of the supporting space structure. It is therefore necessary to minimize the magnitudes of the forces and moments transmitted to the base. It is shown that kinematic redundancy can be used to solve the dynamic problem of minimizing...
Topics: CRACK PROPAGATION, STRAIN RATE, THERMAL FATIGUE, CREEP PROPERTIES, FRACTURE MECHANICS, METAL...
A common method of treating the mean stress effect on fatigue life is to displace the elastic line on a Manson-Coffin-Basquin diagram while retaining the position of the plastic line. Manson and Halford pointed out that this procedure implies that mean stress significantly affects the cyclic stress-strain curve. Actually, however, they showed experimentally and by more general reasoning, that mean stress has little, if any, effect on the cyclic stress-strain curve. Thus, they concluded that it...
Topics: NASA Technical Reports Server (NTRS), FATIGUE LIFE, METAL FATIGUE, S-N DIAGRAMS, STRESSES, ALUMINUM...
256
256
May 29, 2011
05/11
by
Parker, P. A
texts
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This paper provides an overview of force measurement at the National Transonic Facility (NTF). The NTF has unique force measurement requirements that dictate an integration of all aspects of balance design, production, and calibration. An overview of current force measurement capabilities is provided along with new balance development efforts. Research activities in the areas of thermal compensation and balance calibration are presented. Also, areas of future research are detailed.
Topics: FATIGUE LIFE, HIGH TEMPERATURE, STRESS-STRAIN RELATIONSHIPS, COST EFFECTIVENESS, METAL FATIGUE,...
Historically both sensitivity level 3 and sensitivity level 4 fluorescent penetrants have been used to perform NASA Standard Level inspections of aerospace hardware. In April 2008, NASA-STD-5009 established a requirement that only sensitivity level 4 penetrants were acceptable for inspections of NASA hardware. Having NASA contractors change existing processes or perform demonstration tests to certify sensitivity level 3 penetrants posed a potentially huge cost to the Agency. This study was...
Topics: NASA Technical Reports Server (NTRS), INSPECTION, QUALITY CONTROL, NONDESTRUCTIVE TESTS, CRACKS,...
Compared are closure data produced on the same specimen by the crack tip compliance gage and electric potential techniques. Experiments on 7075-T651 aluminum center cracked panels produced equivalent results on closure using the two techniques. The results also indicated that closure is a function of stress ratio, specimen thickness and maximum applied stress intensity. Maximum stress intensity had a strong effect on closure in the range of applied stresses used. This dependence of closure on...
Topics: NASA Technical Reports Server (NTRS), ALUMINUM, CLOSURES, CRACKING (FRACTURING), ELECTRIC...
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219
Jul 26, 2010
07/10
by
Deck, Bruce; Wahlen, Martin; Weyer, Harley; Kubik, Peter; Sharma, Pankaj; Gove, Harr
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Initial measurements of the cosmogenic radionuclide, Cl-36, in the lower stratosphere were made by accelerator mass spectrometry. Samples were obtained using the large volume LASL air sampling pods on a NASA WB-57F aircraft. Untreated (for collection of particulates only) and tetrabutyl ammonium hydroxide treated (for collection of particulates and HCl) IPC-1478 filters were flown on three flights in the lower stratosphere. Chlorine (Cl) and Cl compounds are important trace constituents for...
Topics: CREEP PROPERTIES, DAMAGE, DESTRUCTIVE TESTS, FATIGUE LIFE, CYCLIC LOADS, FAILURE ANALYSIS, FATIGUE...
287
287
May 27, 2011
05/11
by
Stecker, F. W
texts
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We discuss the determination of the intergalactic pair-production absorption coefficient as derived by Stecker and De Jager by making use of a new empirically based calculation of the spectral energy distribution of the intergalactic infrared radiation field as given by Malkan and Stecker. We show that the results of the Malkan and Stecker calculation agree well with recent data on the infrared background. We then show that Whipple observations of the flaring gamma-ray spectrum of Mrk 421 hint...
Topics: TITANIUM ALLOYS, COMPUTER PROGRAMS, CRACK INITIATION, ALUMINUM ALLOYS, CRACK PROPAGATION, METAL...
It is generally recognized that in any well behaved metal fatigue failure, the following sequence of events occurs. The application of stress causes the movement of defects already present in the specimen, besides producing new defects. These defects concentrate in the regions of stress concentration. This defect concentration, which precedes crack nucleation and its eventual growth, actually amounts to environmental changes for Mossbauer atoms located in these regions. Changes in the atomic...
Topics: NASA Technical Reports Server (NTRS), METAL FATIGUE, MOSSBAUER EFFECT, NONDESTRUCTIVE TESTS,...
181
181
Jul 26, 2010
07/10
by
Grantham, William L
texts
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Two questions are addressed: (1) which future missions need Controls-Structures Interaction (CSI) technology for implementing large spacecraft in orbit; and (2) what specific benefits are to be derived if the technology is available The answers to these questions were used to help formulate and direct the CSI technology development program. Many future NASA missions have common CSI technology needs which can best be developed in a broad-based, but focused, technology program to provide the...
Topics: BEARINGS, NUCLEATION, PLASTIC PROPERTIES, STRESS INTENSITY FACTORS, TURBINE PUMPS, FAILURE...
An electron-bombardment Hg ion thruster was used as an ion source to texture surfaces of materials used to make orthopedic and/or dental prostheses or implants. The materials textured include 316 stainless steel, titanium-6% aluminum, 4% vanadium, and cobalt-20% chromium, 15% tungsten. To determine the effect of ion texturing on the ultimate strength and yield strength, stainless steel and Co-Cr-W alloy samples were tensile tested to failure. Three types of samples of both materials were...
Topics: NASA Technical Reports Server (NTRS), ELECTRON BOMBARDMENT, METAL FATIGUE, PROSTHETIC DEVICES,...
The effects of welding, five selected surface coatings, and stress relieving on the thermal fatigue resistance of H-13 Die Steel for aluminum die casting dies were studied using eleven thermal fatigue specimens. Stress relieving was conducted after each 5,000 cycle interval at 1050 F for three hours. Four thermal fatigue specimens were welded with H-13 or maraging steel welding rods at ambient and elevated temperatures and subsequently, subjected to different post-weld heat treatments. Crack...
Topics: NASA Technical Reports Server (NTRS), DIES, FATIGUE LIFE, FRACTURE STRENGTH, METAL FATIGUE, STEELS,...
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...
Topics: NASA Technical Reports Server (NTRS), CRACK INITIATION, ENVIRONMENTAL TESTS, HIGH STRENGTH ALLOYS,...
The fundamental concepts of the strainrange partitioning approach to high temperature, low low-cycle fatigue are reviewed. Procedures are presented by which the partitioned strainrange versus life relationships for any material can be generated. Laboratory tests are suggested for further verifying the ability of the method of strainrange partitioning to predict life.
Topics: NASA Technical Reports Server (NTRS), FATIGUE LIFE, METAL FATIGUE, STRAIN RATE, CYCLIC LOADS,...
A computer program is described which can be used to predict the thermal fatigue life of metals and structural components from conventional metal properties. A unique feature of TFLIFE is that it calculates lives according to several different failure criteria for the same input data. These criteria are surface crack initiation, interior crack initiation, and complete fracture of both unnotched and notched fatigue specimens. Sample output tables are shown, together with results for two typical...
Topics: NASA Technical Reports Server (NTRS), METAL FATIGUE, PREDICTION ANALYSIS TECHNIQUES, THERMAL...
Structural modifications to the 34-m hour-angle-declination antennas, coupled with the use of the antennas beyond their intended lifespans, have led to structural fatigue, as evidenced by damage to the declination drive gear and cracks on the structural members and gussets. An analysis and simulation were made of the main antenna structural members. The analysis showed that the total stress to the antenna structure substantially exceeds the maximum levels recommended by the American Institute...
Topics: NASA Technical Reports Server (NTRS), ANTENNAS, CRACKS, DEEP SPACE NETWORK, METAL FATIGUE, STEELS,...
Literature survey was conducted to determine the effects of different microstructural features and different load histories on fatigue crack initiation and propagation of aluminum alloys. Comparison of microstructure and monotonic and cyclic properties between powder metallurgy (P/M) and ingot metallurgy (I/M) alloys is presented. The two alloys that are representative of each process on which the comparison is focused are X7091 and 7050. Included is a detailed description of the microstructure...
Topics: NASA Technical Reports Server (NTRS), ALUMINUM ALLOYS, CRACK INITIATION, CRACK PROPAGATION, METAL...
AMS 5749 steel combines the tempering, hot hardness, and hardness retention characteristics of AISI M-50 steel with the corrosion and oxidation resistance of AISI 440C stainless steel. The five-ball fatigue tester was used to evaluate the rolling-element fatigue life of AMS 5749. Double vacuum melting (vacuum induction melting plus vacuum arc remelting, VIM-VAR) produced AMS 5749 material with a rolling-element fatigue life at least 14 times that of vacuum induction melting alone. The VIM-VAR...
Topics: NASA Technical Reports Server (NTRS), AUSTENITE, BEARING ALLOYS, STEELS, VACUUM MELTING, BEARINGS,...
Mean-stress effects on fatigue life are critical in isothermal and thermomechanically loaded materials and composites. Unfortunately, existing mean-stress life-prediction methods do not incorporate physical fatigue damage mechanisms. An objective is to examine the relation between mean-stress induced damage (as measured by acoustic emission) and existing life-prediction methods. Acoustic emission instrumentation has indicated that, as with static yielding, fatigue damage results from...
Topics: NASA Technical Reports Server (NTRS), DAMAGE ASSESSMENT, LIFE (DURABILITY), METAL FATIGUE,...
318
318
Jul 23, 2010
07/10
by
Perkinson, Do
texts
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An overview is given in viewgraph form of orbital transfer vehicle concept definition and systems analysis studies. Project development flow charts are shown for key milestones from 1985 until 1997. Diagrams of vehicles are given. Information is presented in outline form on technology requirements, cooling of propellant tanks, cryogenic fluid management, quick connect/disconnect fluid interfaces and propellant mass transfer.
Topics: CRACK INITIATION, PROTECTIVE COATINGS, STRESS-STRAIN RELATIONSHIPS, CRACK PROPAGATION, FATIGUE...
Additional support is presented for the previously proposed role of hydrogen as an embrittling agent in hot-salt stress corrosion cracking of titanium-aluminum alloys. The main source of hydrogen formed during the reactions of titanium alloys with hot salt was identified as water associated with the salt. Hydrogen is produced by the reaction of an intermediate (hydrogen halide) with the alloy rather than from metal-water reactions. The fracture mode of precracked tensile specimens was ductile...
Topics: NASA Technical Reports Server (NTRS), ALUMINUM ALLOYS, EMBRITTLEMENT, HYDROGEN, SALT BATHS, STRESS...
Low mass bearing balls with hardened iron-plated surfaces can eliminate problems of low fatigue strength and flexure fatigue, and lead to increased life and reliability of high speed ball bearings. Low mass balls exert lower centrifugal forces on outer race of bearing thus eliminating detrimental effect of high speed operation.
Topics: NASA Technical Reports Server (NTRS), BALL BEARINGS, CARBON STEELS, FRICTION REDUCTION, HARDENING...
Solid specimens of the alloy Inconel 903 (iron based alloy) were exposed to four gaseous environments and high temperatures. Air, pure helium, pure hydrogen, and hydrogen and water vapor combined were the gaseous environments employed, and the temperature was 1400 F. Various mechanical property tests (low cycle fatigue, creep-rupture, tensile properties) were performed on the alloy. Results indicate that the hydrogen and water vapor environment cause a sharp reduction in the mechanical...
Topics: NASA Technical Reports Server (NTRS), GAS-METAL INTERACTIONS, HYDROGEN, IRON ALLOYS, MECHANICAL...
The useful life of the wire probe in an ultrasonic kidney stone disintegration instrument is enhanced and prolonged by attaching the wire of the wire probe to the tip of an ultrasonic transducer by means of a clamping arrangement. Additionally, damping material is applied to the wire probe in the form of a damper tube through which the wire probe passes in the region adjacent the transducer tip. The damper tube extends outwardly from the transducer tip a predetermined distance, terminating in a...
Topics: NASA Technical Reports Server (NTRS), CALCULI, DAMPING, KIDNEYS, LIFE (DURABILITY), ULTRASONIC WAVE...
The use of fracture mechanics for predicting fracture and fatigue crack growth in metals is presented.
Topics: NASA Technical Reports Server (NTRS), CRYOGENIC WIND TUNNELS, FRACTURE MECHANICS, WIND TUNNEL...
The effect of a constant applied stress in crack initiation of aluminum 2014-T6, 7075-T651 and titanium 6A1-4V has been investigated. Aluminum c-ring specimens (1-inch diameter) and u-band titanium samples were exposed continuously to a 3.5% NaCl solution (pH 6) and organic fluids of ethyl, methyl, and iso-propyl alcohol (reagent purity). Corrosive action was observed to begin during the first and second day of constant exposure as evidenced by accumulation of hydrogen bubbles on the surface of...
Topics: NASA Technical Reports Server (NTRS), ALUMINUM ALLOYS, CRACK INITIATION, ORGANIC LIQUIDS, SALT...
The fatigue damage interaction behavior of PWA 1480 single crystal alloy has been experimentally established for the two-level loading case in which a block of low-cycle fatigue loading is followed by high-cycle fatigue loading to failure. A relative life ratio N1/N2 (where N1 and N2 are the low- and high-cycle fatigue baseline lives, respectively) of approximately 0.002 was explored to assess the interaction behavior. The experimental results thus far show evidence of a loading order...
Topics: NASA Technical Reports Server (NTRS), FATIGUE LIFE, FATIGUE TESTS, HEAT RESISTANT ALLOYS, LOADS...
A computerized tool for the analysis of time independent cyclic plasticity structural response, life to crack initiation prediction, and crack growth rate prediction for metallic materials is described. Three analytical items are combined: the finite element method with its associated numerical techniques for idealization of the structural component, cyclic plasticity models for idealization of the material behavior, and damage accumulation criteria for the fatigue failure.
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, CRACK INITIATION, CYCLIC LOADS, METAL...
The potential use of thin guage 2219 aluminum alloy for airborne liquid hydrogen tankage was examined. Existing data were processed using the Newman two parameter equation, a prediction was made for the life expectancy of a hypothetical liquid hydrogen tank, and additional experimental data were generated in an attempt to correct the deficiencies in the existing data.
Topics: NASA Technical Reports Server (NTRS), ALUMINUM ALLOYS, CRYOGENIC FLUID STORAGE, FUEL TANKS,...
Fatigue crack growth (FCG) research conducted in the near threshold regime has identified a room temperature creep crack growth damage mechanism for a fine grain powder metallurgy (PM) aluminum alloy (8009). At very low (Delta) K, an abrupt acceleration in room temperature FCG rate occurs at high stress ratio (R = K(sub min)/K(sub max)). The near threshold accelerated FCG rates are exacerbated by increased levels of K(sub max) (K(sub max) = 0.4 K(sub IC)). Detailed fractographic analysis...
Topics: NASA Technical Reports Server (NTRS), ALUMINUM ALLOYS, CRACK PROPAGATION, METAL FATIGUE, POWDER...
