207
207

Jun 19, 2010
06/10

by
Finkel, V. M.; Kutkin, I. A.; Zuyev, L. B

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Stress distribution at vertex of growing crack

Topics: CRACK PROPAGATION, CRACKS, ISOCHROMATICS, STRESS DISTRIBUTION, CRACK PROPAGATION, STRESS...

Journal of Research of the National Bureau of Standards

Topics: plate, stress, complex stress distribution

286
286

May 21, 2011
05/11

by
Aiken, William S , J

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No Abstract Available

Topics: METALS - FRACTURES, DISKS, ROTATING - STRENGTH, DISKS, ROTATING - STRESS DISTRIBUTION, STRESS...

219
219

Jul 5, 2010
07/10

by
Lasalle, J. P

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The abstract theory presented shows how the theory of dissipative systems of ordinary differential equations can be extended to include a wide class of functional and partial differential equations. Since the basic hypotheses are all in terms of boundedness, finding sufficient conditions in terms of Liapunov functions was not difficult. Work is being undertaken to solve some nontrivial examples to illustrate how the theory can applied.

Topics: AFRICA, GEOLOGICAL FAULTS, TECTONICS, VOLCANOLOGY, PETROLOGY, STRESS DISTRIBUTION

161
161

Jul 11, 2010
07/10

by
Kazakos, D

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The problem of estimating the prior probabilities q sub k of a mixture of known density functions f sub k(X), based on a sequence of N statistically independent observations is considered. It is shown that for very mild restrictions on f sub k(X), the maximum likelihood estimate of Q is asymptotically efficient. A recursive algorithm for estimating Q is proposed, analyzed, and optimized. For the M = 2 case, it is possible for the recursive algorithm to achieve the same performance with the...

Topics: CRACK PROPAGATION, FRACTURE MECHANICS, DISPLACEMENT, MATHEMATICAL MODELS, STRESS DISTRIBUTION

610
610

May 27, 2011
05/11

by
VLASOV, V. Z

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GENERAL HOMOGENEOUS SOLUTIONS ARE PRESENTED FOR THE EQUATIONS OF THE MEMBRANE THEORY OF SHELLS OF REVOLUTION OF BOTH POSITIVE AND NEGATIVE GAUSSIAN CURVATURE. SOLUTIONS ARE OBTAINED OF A NUMBER OF BOUNDARY VALUE PROBLEMS OF EDGE-LOADED SHELLS AND COMPOUND SHELLS LOADED AT THEIR JUNCTURES, INCLUDING A COMPOUND SHELL MADE OF CONICAL SEGMENTS WITH STIFFENERS AT THE JUNCTURES.

Topics: BENDING, THIN PLATES, BENDING THEORY, THICKNESS, STRESS DISTRIBUTION, SHEARING

The main objective of this project is to study the characteristics of different alloys such as Steel, Aluminum and Cast Iron and to the design and analyze the stress distribution of the piston with a suitable material above the actual engine condition for a heavy duty diesel engine. In this paper, thermal analysis and mechanical analysis is done. The parameters used for the analysis are operating gas pressure, temperature and material properties of the piston. In I.C. Engine, a piston is most...

Topics: Design and Analyze, Analysis of Piston & Stress Distribution

NASTRAN was chosen as the principal analytical tool for structural analysis of the Illinois Center Plaza Hotel Building in Chicago, Illinois. The building is a 40-story, reinforced concrete structure utilizing a monolithic slab-column system. The displacements, member stresses, and foundation loads due to wind load, live load, and dead load were obtained through a series of NASTRAN runs. These analyses and the input technique are described.

Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, STRUCTURAL ANALYSIS, BUILDINGS, LOADS...

251
251

Jun 17, 2010
06/10

by
Kubenko, V. D

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Analysis of stresses near elliptic hole in thin infinite plate subject to oscillating pressure

Topics: HOLES (MECHANICS), OSCILLATIONS, PRESSURE OSCILLATIONS, STRESS ANALYSIS, STRESS DISTRIBUTION, THIN...

1,268
1.3K

Jul 5, 2010
07/10

by
Dolezalek, H

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No Abstract Available

Topics: ADHESIVE BONDING, LAP JOINTS, STRESS DISTRIBUTION, DIFFERENTIAL EQUATIONS, INTERFACIAL TENSION,...

970
970

Jul 11, 2010
07/10

by
NON

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THEORETICAL AND MEASUREMENTS PROBLEMS OF COSMIC RAY RESEARCH ARE ELABORATED.

Topics: ELASTIC DEFORMATION, NUMERICAL ANALYSIS, SOLIDS, SURFACE DISTORTION, ELASTOHYDRODYNAMICS,...

Improvements to the operational capabilities of NASTRAN are reported. The improvements include the development and implementation of a number of new finite elements into the existing NASTRAN element library and also the development of a finite element heat transfer analysis capability.

Topics: NASA Technical Reports Server (NTRS), COMPUTER AIDED DESIGN, COMPUTER PROGRAMS, HEAT TRANSFER,...

Furnaces are useful for melting different materials for casting process. In this research paper, we had done advanced heat transfer analysis of induction furnace wall made of silica ramming mass using explicit finite difference method. We have divided actual geometry of furnace refractory wall into 14 elements and 24 nodes. We have derived explicit finite difference equations for all 24 nodes. We have calculated temperature distribution and thermal stress distribution for all different nodes...

Topics: Advanced heat transfer analysis, Temperature distribution, Stress distribution, Explicit finite...

Furnaces are useful for melting different materials for casting process. In this research paper, we had done advanced heat transfer analysis of induction furnace wall made of silica ramming mass using explicit finite difference method. We have divided actual geometry of furnace refractory wall into 14 elements and 24 nodes. We have derived explicit finite difference equations for all 24 nodes. We have calculated temperature distribution and thermal stress distribution for all different nodes...

Topics: Advanced heat transfer analysis, Temperature distribution, Stress distribution, Explicit finite...

213
213

Jun 21, 2010
06/10

by
Conel, J. E

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Microwave mass absorption coefficient in granular silicates from plate measurements and effects of scattering

Topics: HOLE DISTRIBUTION (MECHANICS), HOLES (MECHANICS), STRESS DISTRIBUTION, STRESS-STRAIN DIAGRAMS,...

808
808

Jun 20, 2010
06/10

by
Fleishman, N. P.; Savin, G. N

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Stress concentrations in rib-reinforced plates and shells, and effects on structural design

Topics: REINFORCED PLATES, REINFORCED SHELLS, STRESS DISTRIBUTION, STRUCTURAL DESIGN, BENDING THEORY,...

Mapping of the Ethiopian rift and Afar margins revealed the existence of Tertiary dike swarms. The structural relations of these swarms and the fed lava pile to monoclinal warping of the margins partly reflect a style of continental margin tectonics found in other parts of the world. In Ethiopia, however, conjugate dike trends appear to be unusually strongly developed. Relation of dikes to subsequent margin faulting is ambiguous, and there are instances where the two phenomena are spatially...

Topics: NASA Technical Reports Server (NTRS), AFRICA, GEOLOGICAL FAULTS, TECTONICS, VOLCANOLOGY, PETROLOGY,...

An ideal engine mount should be able to completely isolate the engine vibration which is caused due to the engine Noise, Vibration and Harshness characteristics. Vibration in an automobile is due to different parts of the automobile, one of the main sources of vibration is the engine. In engine, the vibration is mainly due to drive trains. Hence, it is very important to optimize the engine mount to reduce vibration at the source itself, to increase the comfort of the passenger. In this paper,...

Topics: Passive Engine Rubber Mount, Finite Element Method, Elastic Characteristics, FEA Modeling,...

26
26

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Furnaces are most commonly used for melting of materials. Induction furnaces are more beneficial as no fuel is required. It is a problem to find life cycle of Induction Melting Furnace Wall under load variation. The induction melting furnace wall is made of alumina ramming mass which is one kind of refractory material. The failure occurs due to cyclic thermal stresses due to heating and cooling cycles. Temperature distribution and thermal stress distribution fields of the induction melting...

Topics: Advanced stress life analysis, Temperature distribution, Stress distribution, explicit finite...

510
510

May 27, 2011
05/11

by
Angelini, Lorella; Christian, Eric; Barthelmy, Scott; Palmer, David; Mitchell, John; Esposito, Joseph; Sreekumar, P.; Hua, Xin-Min; Mandzhavidze, Natalie; Chan, Kai-Wing; Soong, Yang; Corcoran, Michael; Barrett, Paul, et al; Drake, Stephen; McGlynn, Thomas A.; Snowden, Stephen; Mukai, Koji; Cannizzo, John; Lochner, James; Rots, Arnold

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This report reviews activities performed by the members of the USRA contract team during the 6 months of the reporting period and projected activities during the coming 6 months. Activities take place at the Goddard Space Flight Center, within the Laboratory for High Energy Astrophysics. Developments concern instrumentation, observation, data analysis, and theoretical work in astrophysics. Supported missions include advanced Satellite for Cosmology and Astrophysics (ASCA), X-Ray Timing...

Topics: FRETTING, NICKEL COATINGS, METAL SURFACES, ELECTROLESS DEPOSITION, STRESS DISTRIBUTION,...

An ideal engine mount should be able to completely isolate the engine vibration which is caused due to the engine Noise, Vibration and Harshness characteristics. Vibration in an automobile is due to different parts of the automobile, one of the main sources of vibration is the engine. In engine, the vibration is mainly due to drive trains. Hence, it is very important to optimize the engine mount to reduce vibration at the source itself, to increase the comfort of the passenger. In this paper,...

Topics: Passive Engine Rubber Mount, Finite Element Method, Elastic Characteristics, FEA Modeling,...

299
299

Jun 19, 2010
06/10

by
Khoroshun, L. P

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Stress-strain relations in laminar anisotropic medium

Topics: ANISOTROPIC MEDIA, LAMINATES, STRAIN DISTRIBUTION, STRESS DISTRIBUTION, STRESS-STRAIN...

656
656

Jun 21, 2010
06/10

by
VILLMAN, CH. I

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NOCTILUCENT CLOUDS WITH WAVE MOVEMENT, CHEMICAL COMPOSITION, AND WATER VAPOR

Topics: CLADDING, FISSION PRODUCTS, NUCLEAR FUEL ELEMENTS, STRESS DISTRIBUTION, CYLINDRICAL BODIES, FAST...

The general problem of a rectangular plate clamped along two parallel sides and containing a crack parallel to the clamps is considered. The problem is formulated in terms of a system of singular integral equations and the asymptotic behavior of the stress state near the corners is investigated. Numerical examples are considered for a clamped plate without a crack and with a centrally located crack, and the stress intensity factors and the stresses along the clamps are calculated.

Topics: NASA Technical Reports Server (NTRS), CRACK GEOMETRY, CRACK PROPAGATION, METAL PLATES, STRESS...

A computer code which can account for plastic deformation effects on stress generated in silicon sheet grown at high speeds is fully operative. Stress and strain rate distributions are presented for two different sheet temperature profiles. The calculations show that residual stress levels are very sensitive to details of the cooling profile in a sheet with creep. Experimental work has been started in several areas to improve understanding of ribbon temperature profiles and stress distributions...

Topics: NASA Technical Reports Server (NTRS), PLASTIC DEFORMATION, SILICON, TEMPERATURE PROFILES, COMPUTER...

The project is based upon research of Tessler et al. (1994) on an improved variational formulation for post-processing stress predictions in Finite Element Analysis. The methodology, called Smoothing Element Analysis (SEA), employs a three-node smoothing finite element. The present effort focused on verifying the basic constant strain criterion for the three-node smoothing element subject to a set of internal penalty constraints. The convergence characteristics of the element are assessed by...

Topics: NASA Technical Reports Server (NTRS), FINITE ELEMENT METHOD, STRESS ANALYSIS, ERROR FUNCTIONS,...

The indicator is characterized by an elongated elastic body having extended from the opposite ends of threaded shanks adapted to selected tension members. A pair of external shoulders, one of which is axially displaceable relative to the other, and a rigid tubular sleeve interposed between said shoulders are included. Tension is applied to the elastic body for imparting strain. The movable shoulder can be advanced into abutting engagement with the sleeve, whereby the sleeve is placed in...

Topics: NASA Technical Reports Server (NTRS), LOAD DISTRIBUTION (FORCES), TENSILE STRENGTH, ELASTIC...

Rockwell International employed NASTRAN to identify high stress areas in valve products and the mechanical configurations necessary to accommodate them. Also used in seismic and vibration analysis of valves to establish design adequacy under severe conditions, such as those that might occur in an earthquake. Program offers significant savings in analysis effort compared with other analytical approaches.

Topics: NASA Technical Reports Server (NTRS), POWER PLANTS, VALVES, MECHANICAL ENGINEERING, DYNAMIC...

423
423

Jun 1, 2011
06/11

by
Rothrock, Addison M

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For a period of ten to fifteen years intensive research and development has been conducted on turbojet propulsion systems for aircraft. During this period much has been learned about the system both from the standpoint of current usage and of future development possibilities. It is the purpose of this report to discuss the current status of the turbojet engine as produced in the United States and to discuss the future possibilities for improvement in the engine and in the fuel. The engine and...

Topics: FUSELAGES, STIFFNESS, TENSILE TESTS, PANELS, THIN WALLS, COMPRESSION LOADS, MECHANICAL PROPERTIES,...

387
387

Jul 11, 2010
07/10

by
Everette, J. M.; Bradfield, L. D.; Horton, C. L

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Common software was investigated as a method for minimizing development and maintenance cost of the shuttle program information management system (SPIMS) applications while reducing the time-frame of their development. Those requirements satisfying these criteria are presented along with the stand-alone modules which may be used directly by applications. The SPIMS applications operating on the CYBER 74 computer, are specialized information management systems which use System 2000 as a data base...

Topics: AMBIENT TEMPERATURE, TENSILE PROPERTIES, CRACK INITIATION, HELIUM, HYDROGEN, STEELS, CRACK...

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222

Jun 21, 2010
06/10

by
Brocker, D. H.; Kavanaugh, W. P.; Stewart, E. C

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Search algorithm for optimal control computer programming

Topics: FINITE DIFFERENCE THEORY, VISCOPLASTICITY, INFLATABLE STRUCTURES, NONLINEARITY, ANISOTROPIC SHELLS,...

Effects of experimental imprecision on the stress intensity factors calculated for various practical specimen types are shown. A general form equation for the stress intensity factor is presented and a general error equation is derived. The expected error in the stress intensity factor is given in terms of the precision levels of the basic experimental measurements and derivatives of the stress intensity calibration factor. Nine common fracture specimen types are considered, and the sensitivity...

Topics: NASA Technical Reports Server (NTRS), ERRORS, FRACTURE MECHANICS, STRESS DISTRIBUTION, CRACK...

146
146

Jun 12, 2011
06/11

by
McNeal, Curtis, Jr

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Medium lift EELVs may still play a role in manned space flight. To be considered for manned flight, medium lift EELVs must address the short comings in their current boost assist motors. Two options exist: redesign and requalify the solid rocket motors. Replace solid rocket motors (SRMs) with hybrid rocket motors. Hybrid rocket motors are an attractive alternative. They are safer than SRMs. The TRL's Lockheed Martin Small Launch Vehicle booster development substantially lowers the development...

Topics: NONDESTRUCTIVE TESTS, STRESS ANALYSIS, DIMENSIONAL MEASUREMENT, FINITE ELEMENT METHOD, FLYWHEELS,...

Three methods of photoelastic analysis are examined. The first method is an extension of the oblique incidence technique in which the model (or the light beam) is rotated about one of the material symmetry axes. In the second method, transmission and reflection photoelastic responses are combined. The third method requires the drilling of small holes and the determination of the fringe orders at selected points on the hole boundary. The three methods are applied to an orthotropic circular disk...

Topics: NASA Technical Reports Server (NTRS), COMPOSITE STRUCTURES, PHOTOELASTIC ANALYSIS, STRESSES,...

1,105
1.1K

Jul 23, 2010
07/10

by
NON

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Reports on aviation meteorology, most of them informal, are presented by representatives of the National Weather Service, the Bracknell (England) Meteorological Office, the NOAA Wave Propagation Lab., the Fleet Numerical Oceanography Center, and the Aircraft Owners and Pilots Association. Additional presentations are included on aircraft/lidar turbulence comparison, lightning detection and locating systems, objective detection and forecasting of clear air turbulence, comparative verification...

Topics: LEADING EDGES, THERMAL BUCKLING, THERMAL STRESSES, THIN WALLED SHELLS, FINITE ELEMENT METHOD,...

281
281

Jul 11, 2010
07/10

by
Briehl, D.; Reck, G. M

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In order to verify the ultraviolet absorption technique used in the Global Atmospheric Sampling Program, two flight experiments were conducted employing several techniques, both in situ and remote, for measuring atmospheric ozone. The first experiment used the NASA CV-990 equipped with an ultraviolet absorption ozone monitor and an ultraviolet spectrophotometer, a balloon ozonesonde, and a Dobson station for determining and comparing the ozone concentration data. A second experiment compared...

Topics: DYNAMIC RESPONSE, SOLID ROCKET PROPELLANTS, SPACE SHUTTLE BOOSTERS, VISCOELASTICITY, BOOSTER...

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201

May 31, 2011
05/11

by
Frank, Jeremy; Jonsson, Ar

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In this paper we introduce Constraint-based Attribute and Interval Planning (CAIP), a new paradigm for representing and reasoning about plans. The paradigm enables the description of planning domains with time, resources, concurrent activities, mutual exclusions among sets of activities, disjunctive preconditions and conditional effects. We provide a theoretical foundation for the paradigm using a mapping to first order logic. We also show that CAIP plans are naturally expressed by networks of...

Topics: MEDICAL SCIENCE, STRESS DISTRIBUTION, TISSUES (BIOLOGY), SIMULATION, TELEMEDICINE, ELASTIC...

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197

May 21, 2011
05/11

by
Lovell, Powell M , J

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No Abstract Available

Topics: BEAMS, THIN-BENDING, LOADS-BEAMS, THIN, WOODS-SPRUCE, SITKA, STRESS DISTRIBUTION, BEAMS,...

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156

Jun 2, 2011
06/11

by
Rabin, Ro

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This viewgraph presentation provides the results of a survey of 1450 professionals employed by organizations in the remote sensing industry. The survey asked participants about the status of the industry.

Topics: ADHESIVE BONDING, CRACKING (FRACTURING), BONDED JOINTS, LAP JOINTS, FINITE ELEMENT METHOD, STRESS...

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182

May 23, 2011
05/11

by
Christopher, Sundar Anan

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Understanding the role of clouds is one of the highest priority science objectives in the global climate change program. In particular there has been a renewed interest in understanding the cloud radiative interactions in the tropical regions. Although a number of studies have emphasized the importance of cloud optical properties on the earth's radiative energy balance, information concerning cloud optical depth and particle size as a function of cloud type is lacking.

Topics: CRYSTAL GROWTH, DEFORMATION, STRESS DISTRIBUTION, GALLIUM ARSENIDES, TWINNING, SEMICONDUCTORS...

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135

May 23, 2011
05/11

by
Rajpal, Sandeep; Rhee, Do Jun; Lin, Sh

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The first part of this paper presents a simple and systematic technique for constructing multidimensional M-ary phase shift keying (MMK) trellis coded modulation (TCM) codes. The construction is based on a multilevel concatenation approach in which binary convolutional codes with good free branch distances are used as the outer codes and block MPSK modulation codes are used as the inner codes (or the signal spaces). Conditions on phase invariance of these codes are derived and a multistage...

Topics: JOINED WINGS, AIRCRAFT CONFIGURATIONS, WING LOADING, STRESS DISTRIBUTION, LEADING EDGES,...

319
319

May 22, 2011
05/11

by
Divsalar, D.; Pollara, F

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In this article, we introduce multiple turbo codes and a suitable decoder structure derived from an approximation to the maximum a posteriori probability (MAP) decision rule, which is substantially different from the decoder for two-code-based encoders. We analyze the effect of interleaver choice on the weight distribution of the code, and we describe simulation results on the improved performance of these new codes.

Topics: CRACK PROPAGATION, STRAIN DISTRIBUTION, STRESS CONCENTRATION, STRESS DISTRIBUTION, CRACK TIPS,...

214
214

Jul 26, 2010
07/10

by
Brunk, William E.; Flaherty, Richard J

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No Abstract Available

Topics: COLUMNS (SUPPORTS), COMPRESSION TESTS, CREEP STRENGTH, CREEP TESTS, STRESS DISTRIBUTION,...

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172

Jul 11, 2010
07/10

by
Roberts, L

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The classes of large-scale dynamic systems are discussed in terms of modeling with emphasis on air transportation system modeling.

Topics: BUCKLING, CONICAL SHELLS, HONEYCOMB STRUCTURES, PRESSURE EFFECTS, SANDWICH STRUCTURES, COMPUTER...

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342

May 22, 2011
05/11

by
Georgiadis, Nicholas J.; Dudek, Julianne C.; Tierney, Thomas P

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The effects of grid resolution and specification of turbulent inflow boundary conditions were examined using the NPARC code with the Baldwin-Lomax and Chien k-e turbulence models. Three benchmark turbulent test cases were calculated: two were wall bounded flows and the third was a compressible mixing layer. The wall bounded flows were essentially insensitive to axial grid density; however, the location of the first point off the wall had a substantial effect on flow solutions. It was determined...

Topics: ANISOTROPY, COMPRESSION LOADS, STRESS DISTRIBUTION, ELASTOSTATICS, LAMINATES, OPENINGS, RECTANGULAR...

Theory is stated in terms of increments of displacement and stress, and of instantaneous or accumulated values of stress. The equilibrium equations, in the absence of body forces, are written, along with constitutive relations for plane strain.

Topics: NASA Technical Reports Server (NTRS), CRACK PROPAGATION, FRACTURE MECHANICS, DISPLACEMENT,...

The appearance of the terrace like fracture morphology of gaseous hydrogen induced crack growth in acicular alpha-beta titanium alloys is discussed as a function of specimen configuration, magnitude of applied stress intensity, test temperature, and hydrogen pressure. Although the overall appearance of the terrace structure remained essentially unchanged, a distinguishable variation is found in the size of the individual terrace steps, and step size is found to be inversely dependent upon the...

Topics: NASA Technical Reports Server (NTRS), CRACK PROPAGATION, HYDROGEN, TITANIUM ALLOYS, GAS PRESSURE,...

The boundary integral equation method was applied in the solution of the plane elastoplastic problems. The use of this method was illustrated by obtaining stress and strain distributions for a number of specimens with a single edge notch and subjected to pure bending. The boundary integral equation method reduced the non-homogeneous biharmonic equation to two coupled Fredholm-type integral equations. These integral equations were replaced by a system of simultaneous algebraic equations and...

Topics: NASA Technical Reports Server (NTRS), ELASTOPLASTICITY, INTEGRAL EQUATIONS, V GROOVES, STRAIN...

Lunar samples contain abundant open microcracks that have closure characteristics completely unlike any shocked terrestrial rock; however, the microcracks present in the lunar rocks before the rocks reached the surface of the moon were likely similar to the microcracks in the shocked terrestrial rocks. Because the microcracks present in the lunar rocks in situ inside the moon were different, radically different, from the microcracks present today in returned lunar samples, any property that is...

Topics: NASA Technical Reports Server (NTRS), LUNAR ROCKS, MICROCRACKS, PETROGRAPHY, SELENOLOGY, ELECTRON...

Sliding friction experiments, conducted in vacuum with silicon carbide /000/ surface in contact with iron based binary alloys are described. Multiangular and spherical wear particles of silicon carbide are observed as a result of multipass sliding. The multiangular particles are produced by primary and secondary cracking of cleavage planes /000/, /10(-1)0/, and /11(-2)0/ under the Hertzian stress field or local inelastic deformation zone. The spherical particles may be produced by two...

Topics: NASA Technical Reports Server (NTRS), SILICON CARBIDES, SPALLING, WEAR, BINARY ALLOYS, CRYSTAL...