Accurate nomographs for designing conventional skin-stringer and honeycomb sandwich construction to meet sonic fatigue requirements are presented. The nomographs were derived from the results of sonic fatigue tests of 30 skin-stringer and 30 honeycomb sandwich designs, totaling 60 test specimens for each design. Emphasis is also placed on assessing the effect of structural curvature on sonic fatigue and structural response. Nomographs for determining the curvature effects are included. (Author)
Topics: DTIC Archive, Ballentine, John R, LOCKHEED-GEORGIA CO MARIETTA, *PANELS, *AIRFRAMES, STRESSES,...
A simple analysis method has been developed for predicting the residual compression strength of impact-damaged sandwich panels. The method is tailored for honeycomb core-based sandwich specimens that exhibit an indentation growth failure mode under axial compression loading, which is driven largely by the crushing behavior of the core material. The analysis method is in the form of a finite element model, where the impact-damaged facesheet is represented using shell elements and the core...
Topics: NASA Technical Reports Server (NTRS), COMPRESSION TESTS, RESIDUAL STRENGTH, SANDWICH STRUCTURES,...
Intertanks, the structure between tanks of launch vehicles, are prime candidates for weight reduction of rockets. This paper discusses the optimization and detailed analysis of a 96 in (2.44 m) diameter, 77 in (1.85 m) tall intertank. The structure has composite face sheets and an aluminum honeycomb core. The ends taper to a thick built up laminate for a double lap bolted shear joint. It is made in 8 full length panels joined with bonded double lap joints. The nominal load is 4000 lb/in (7 x...
Topics: NASA Technical Reports Server (NTRS), DESIGN ANALYSIS, OPTIMIZATION, HONEYCOMB STRUCTURES, WEIGHT...
The Orbiter radiator system consists of eight individual 4.6 m x 3.2 m panels located with four on each payload bay door. Forward panels #1 and #2 are 2.3 cm thick while the aft panels #3 and #4 have a smaller overall thickness of 1.3 cm. The honeycomb radiator panels consist of 0.028 cm thick Aluminum 2024-T81 facesheets and Al5056-H39 cores. The face-sheets are topped with 0.005 in. (0.127 mm) silver-Teflon tape. The radiators are located on the inside of the shuttle payload bay doors, which...
Topics: NASA Technical Reports Server (NTRS), IMPACT DAMAGE, SPACE DEBRIS, SPACE SHUTTLE PAYLOADS,...
The Curved Duct Test Rig (CDTR) has been developed to investigate sound propagation through a duct of size comparable to the aft bypass duct of typical aircraft engines. The axial dimension of the bypass duct is often curved and this geometric characteristic is captured in the CDTR. The semiannular bypass duct is simulated by a rectangular test section in which the height corresponds to the circumferential dimension and the width corresponds to the radial dimension. The liner samples are...
Topics: NASA Technical Reports Server (NTRS), NACELLES, SOUND PROPAGATION, LININGS, DUCTS, AIRCRAFT...
The combined load (mechanical or thermal load) buckling equations were established for orthotropic rectangular sandwich panels under four different edge conditions by using the Rayleigh-Ritz method of minimizing the total potential energy of a structural system. Two-dimensional buckling interaction curves and three-dimensional buckling interaction surfaces were constructed for high-temperature honeycomb-core sandwich panels supported under four different edge conditions. The interaction...
Topics: NASA Technical Reports Server (NTRS), DEFORMATION, RAYLEIGH-RITZ METHOD, SANDWICH STRUCTURES,...
Phenolic-nylon and elastomeric target materials were struck with 1.59-mm-diameter aluminum spheres traveling at 4 km/s. The ablative materials were tested at temperatures of 144 deg, 294 deg, and 422 deg K in evacuable test fixtures. Observed crater volumes were so irregular in shape that it was not possible to determine easily the effects of temperature and material independently from measurement error. Therefore, an analysis-of-variance technique was applied to experimental impact data to...
Topics: DTIC Archive, Tippens, Paul E., NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY...
Procedures have been developed by engineers at Sacramento Air Logistics Center to detect active corrosion in aluminum structure and moisture-degraded adhesive bonding in composite honeycomb using acoustic emission monitoring. Simple heating methods employing a hot air gun or heat lamp are used to increase emission from active corrosion sources, and to create the stresses necessary to break moisture-degraded adhesive bonds. Corrosion detection in aluminum skin and honeycomb core has proven very...
Topics: DTIC Archive, Rodgers, John, SACRAMENTO AIR LOGISTICS CENTER MCCLELLAN AFB CA, *DEFECTS(MATERIALS),...
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May 27, 2011
05/11
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Conti, Raul J
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Two circular conical configurations having 15 deg half-angles were tested in laminar boundary layer at a Mach number of 6 and angles of attack up to 90 deg. One cone had a sharp nose and a fineness ratio of 1.87 and the other had a spherically blunted nose with a bluntness ratio of 0.1428 and a fineness ratio of 1.66. Pressure measurements and schlieren pictures of the flow showed that near-conical flow existed up to an angle of attack of approximately 60 deg. At angles of attack above 70 deg...
Topics: SANDWICH STRUCTURES, SUPERSONIC SPEED, BLOWDOWN WIND TUNNELS, THERMAL ANALYSIS, SURFACE ROUGHNESS,...
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May 30, 2011
05/11
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Bull, Barton; Grant, Charles; Morgan, Dwayne; Streich, Ro
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Personnel from the Goddard Space Flight Center Wallops Flight Facility (GSFC/WFF) in Virginia are responsible for the overall management of the NASA Sounding Rocket and Scientific Balloon Programs. Payloads are generally in support of NASA's Space Science Enterprise's missions and return a variety of scientific data as well as providing a reasonably economical means of conducting engineering tests for instruments and devices used on satellites and other spacecraft. Sounding rockets used by NASA...
Topics: CONDUCTIVE HEAT TRANSFER, FINITE VOLUME METHOD, HONEYCOMB CORES, PANELS, THERMAL CONDUCTIVITY,...
Three syntactic core materials were evaluated: (1) HX501 epoxy/A24X glass microballoons, (2) HX501/Carbo-Spheres, and (3) HX592 bis-maleimide/A24X. After optimum B-staging and cure cycles were developed, the following core properties were determined: (1) density, (2) saturation moisture content (140 deg F/92% RH), (3) compressive strength, and (4) effect of thermal cycling on microstructure and water pickup. Sandwiched core panels were fabricated by cocuring B-staged core sheets between two...
Topics: DTIC Archive, Grimm, T. C., MCDONNELL AIRCRAFT CORP ST LOUIS MO, *LAMINATES, *EPOXY COMPOSITES,...
The XV-15, N703NA Tiltrotor Research Aircraft located at the NASA Ames Research Center, Moffett Field, California, currently uses a set of composite rotor blades of complex shape known as the advanced technology blades (ATBs). The main structural element of the blades is a D-spar constructed of unidirectional, angled fiberglass/graphite, with the aft fairing portion of the blades constructed of a fiberglass cross-ply skin bonded to a Nomex honeycomb core. The blade tip is a removable laminate...
Topics: NASA Technical Reports Server (NTRS), BLADE TIPS, COMPOSITE STRUCTURES, FLIGHT TESTS, GLASS FIBERS,...
Various topics relating to composite structural materials for use in aircraft structures are discussed. The mechanical properties of high performance carbon fibers, carbon fiber-epoxy interface bonds, composite fractures, residual stress in high modulus and high strength carbon fibers, fatigue in composite materials, and the mechanical properties of polymeric matrix composite laminates are among the topics discussed.
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT CONSTRUCTION MATERIALS, CARBON FIBER REINFORCED...
Thermostructural analysis was performed on a heated titanium honeycomb-core sandwich panel. The sandwich panel was supported at its four edges with spar-like substructures that acted as heat sinks, which are generally not considered in the classical analysis. One side of the panel was heated to high temperature to simulate aerodynamic heating during hypersonic flight. Two types of surface heating were considered: (1) flat-temperature profile, which ignores the effect of edge heat sinks, and (2)...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC HEATING, AIRCRAFT STRUCTURES, STRUCTURAL...
As a result of the US Army Materiel Command's 'Adhesive Bonding Improvement Initiative,' the US Army Armament Research, Development and Engineering Center (ARDEC) and the US Army Materiels Technology Laboratory (MTL) are conducting this international symposium with the theme 'to improve the design, technology, production and testing of adhesive bonded joints for military and aerospace application'. The Army Materiel Command is placing increased emphasis on the proper application of adhesive...
Topics: DTIC Archive, ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL N J...
The HME resin formulation and synthesis procedure were optimized to yield a stable resin. Composite and honeycomb sandwich panels were vacuum bag molded and provided low resin flow during cure. The resultant composite and sandwich panels demonstrated excellent moisture resistance and suitability for service at 275 F. Also the cocured sandwich panels provided equivalent flatwise tensile strength values to secondary bonded panels.
Topics: DTIC Archive, Vaughan, R W, Zakrzewski, G A, TRW SYSTEMS GROUP REDONDO BEACH CA, *EPOXY RESINS,...
The dynamically similar structural model of the preceding contract (See AD-416 784) was redesigned and reworked to improve the simulation. The sandwich structure simulation, the backing board simulation, the intake ducting simulation were improved. Some previously discovered errors in simulation were corrected. The reworked model was then Vibroacoustically tested. The results of this testing were compared to the results of the actual fuselage portion testing of the previous contract. The model...
Topics: DTIC Archive, NORTHROP CORP HAWTHORNE CA NORAIR DIV, *FUSELAGES, *AIRCRAFT MODELS, *AIRFRAMES,...
The U.S. Army Natick Laboratories modified a method of footwear construction known as Direct Molded Sole (DMS) for the Army's tropical and all- leather combat boots. NLABS developed the special component materials, boot designs and fabrication techniques required to produce military footwear by the DMS process. The sole and heel of the new DMS boots are molded directly to the boot uppers on high-pressure vulcanizing machines, eliminating the sole stitching and heel nailing which were the major...
Topics: DTIC Archive, Park, Alice F, ARMY NATICK LABS MA CLOTHING AND ORGANIC MATERIALS LAB, *SHOES, ARMY...
Mathematically exact equations of the deflections required for a circular cylinder to buckle into a developable polyhedral shape are derived. From this equation it is seen that the tangential displacement can be readily related to the radial displacement. The exact formulas for coefficients of a Fourier series representing the radial displacements are derived for a buckled circular cylinder having any longitudinal and circumferential mode numbers. This is in contrast to earlier work in which...
Topics: DTIC Archive, Fuka, Louis R, TEXAS UNIV AT AUSTIN ENGINEERING MECHANICS RESEARCH LAB,...
This book describes the production version of the B-2707. Minimal differences will exist between the production and prototype airplanes because of availability of materials, processes, and facilities. A general discussion is presented of the structural design. A complete description is included of structural design features of the wing, fuselage, empennage, control surfaces, and landing gear, including drawings of all major assemblies. A preliminary stress analysis discusses methods of...
Topics: DTIC Archive, Johnson, John E, BOEING CO SEATTLE WA SUPERSONIC TRANSPORT DIV, *JET TRANSPORT...
Work performed in the last three phases of the program included: (1) face sheet processing; (2) honeycomb core manufacture; (3) face sheet-to-core bonding development; and (4) sandwich panel fabrication and testing. Resin cure studies were a major portion of this effort since processing problems traced to the polyimide matrix resin had to be resolved before quality core and face sheets could be fabricated. Honeycomb core fabrication and testing were conducted by Hexcel Corporation. A total of...
Topics: NASA Technical Reports Server (NTRS), HEAT SHIELDING, HONEYCOMB CORES, SANDWICH STRUCTURES, SPACE...
The local and general buckling behavior of graphite/polyimide sandwich panels simply supported along all four edges and loaded in uniaxial edgewise compression was investigated. Material properties of adhesive and facings were determined from flatwise tension and sandwich beam flexure tests. Tensile and compressive material properties of the facings were determined at 116, R.T., and 589 K (-250, R.T., and 600 F) using the sandwich beam flexure test method. Results indicate that Gr/PI is a...
Topics: NASA Technical Reports Server (NTRS), BUCKLING, COMPRESSION TESTS, GRAPHITE-POLYIMIDE COMPOSITES,...
Finite element thermal stress analysis was performed on a rectangular titanium honecomb-core sandwich panel which is subjected to thermal load with a temperature gradient across its depth. The distributions of normal stresses in the face sheets and the face-sheet/sandwich-core interfacial shear stresses are presented. The thermal buckling of the heated face sheet was analyzed by assuming the face sheet to be resting on an elastic foundation representing the sandwich core. Thermal buckling...
Topics: NASA Technical Reports Server (NTRS), FINITE ELEMENT METHOD, HONEYCOMB CORES, STRESS ANALYSIS,...
This study examines two test methods to evaluate the peel toughness of the skin to core debond of sandwich panels. The methods tested were the climbing drum (CD) peel test and the double cantilever beam (DCB) test. While the CD peel test is only intended for qualitative measurements, it is shown in this study that qualitative measurements can be performed and compare well with DCB test data. It is also shown that artificially stiffening the facesheets of a DCB specimen can cause the test to...
Topics: NASA Technical Reports Server (NTRS), CANTILEVER BEAMS, JOINTS (JUNCTIONS), SANDWICH STRUCTURES,...
In January 2007, the NASA Administrator and Associate Administrator for the Exploration Systems Mission Directorate chartered the NASA Engineering and Safety Center (NESC) to design, build, and test a full-scale Composite Crew Module (CCM). For the design and manufacturing of the CCM, the team adopted the building block approach where design and manufacturing risks were mitigated through manufacturing trials and structural testing at various levels of complexity. Following NASA's Structural...
Topics: NASA Technical Reports Server (NTRS), SPACECRAFT MODULES, FULL SCALE TESTS, HONEYCOMB CORES,...
No abstract available
Topics: NASA Technical Reports Server (NTRS), SURFACE LAYERS, HONEYCOMB CORES, DEBONDING (MATERIALS),...
Developments in the program of research in composite construction for flight vehicles conducted by the U. S. Forest Products Laboratory during 1958 are summarized. In general the approach has been to derive design criteria mathematically, and then to check by test. Four technical reports issued during the fiscal year are abstracted.
Topics: DTIC Archive, COLEMAN, DONALD G, AERONAUTICAL SYSTEMS DIV WRIGHT-PATTERSON AFB OH, *METALS,...
Topics: DTIC Archive, PRATT, D S, GENERAL DYNAMICS CORP POMONA CA POMONA DIV, *CERAMIC MATERIALS,...
Topics: DTIC Archive, HEXCEL PRODUCTS INC BERKELEY CA, *CONTAINERS, ABSORPTION, ACCELERATION, ALUMINUM...
Design graphs, formulas and procedures for the design and evaluation of the electrical performance of metal space frame radomes is presented covering specifically transmission loss, boresight error, and side-lobe variation. The relative merits of metal and dielectric elements is analyzed. The study consists of developing a straight forward simple procedure for the optimum sizing of solid beam elements for large space frame radomes. Equations were derived expressing the relationship between the...
Topics: DTIC Archive, TRG INC EAST BOSTON MA, *RADOMES, *HONEYCOMB STRUCTURES, PERFORMANCE(ENGINEERING),...
The effects of absorbed moisture on the energy-dissipating characteristics of paper honeycomb were first studied in the Structural Mechanics Research Laboratory at the University of Texas at Austin and reported in 1959. In this study, results of the former study are reexamined and most of the earlier experimental work is repeated using improved techniques. Results indicate that moisture content has no significant effect on average crushing strength, or the energy-dissipating capacity of paper...
Topics: DTIC Archive, Ripperger, E A, TEXAS UNIV AT AUSTIN ENGINEERING MECHANICS RESEARCH LAB, *MOISTURE...
Damping characteristics of honeycomb sandwich construction are studied experimentally. Tests are made on a series of constant section cantilever beams with aluminum alloy facings and cores. The beams have equal depths, but have a range of core heights varying from 0 (solid beam) to 0.8 of the beam depth. The resonant amplification factor in forced vibration and the logarithmic decrement in free vibration are found for the fundamental mode. A theoretical analysis is performed, based on the...
Topics: DTIC Archive, Van Hoof, Eugene R, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *HONEYCOMB CORES,...
A survey of Army aircraft structural failures caused by corrosion, Fatigue, and abrasion was made to define critical areas of future structural research. The primary source of data was the Army failure reports, 'Equipment Improvement Recommendation'. Because of the great number of reports available, a sampling was made consisting of basic airframe failures on four helicopters and two fixed-wing aircraft for the period 1 January 1963 to 31 August 1963. The reports were analyzed individually, and...
Topics: DTIC Archive, OKLAHOMA UNIV RESEARCH INST NORMAN, *AIRFRAMES, ABRASIVES, AIRCRAFT, BONDED JOINTS,...
The principles of static and dynamic similitude were applied to typical complex structural components for the purpose of examining the application of modeling techniques to sonic fatigue predictions. Modeled specimens of curved panels, honeycomb sandwich flat panels, and honeycomb sandwich cantilever beams have been tested. The tests were conducted on full scale 5/8, and 3/8 size models. The tests and analyses demonstrated that scale reductions of linear panel dimensions, and other size factors...
Topics: DTIC Archive, Wang, P, NORTH AMERICAN AVIATION INC LOS ANGELES CA LOS ANGELES DIV, *STRUCTURAL...
Complementary analytical and empirical techniques for the design of energy dissipater configurations for airdropped items are presented. The techniques are applicable to the use of single-shot, sheet-type energy dissipater materials which have an essentially rectangular stress-strain curve for the greatest part of their deformation, such as paper honeycomb, metal honeycombs, and certain foamed plastics.
Topics: DTIC Archive, Gionfriddo, Maurice P, ARMY NATICK LABS MA AIRDROP ENGINEERING LAB, *SHOCK ABSORBERS,...
This program was conducted to develop and demonstrate manufacturing technologies for the structural application of Celion graphite/LARC-160 polyimide composite material. The program consisted of two parts: Process Development and Fabrication of Demonstration Components. Process development included establishing quality assurance of the basic composite material and processing, nondestructive inspection of fabricated components, developing processes for specific structural forms, and...
Topics: DTIC Archive, Frost, R. K., ROCKWELL INTERNATIONAL DOWNEY CA, *LAMINATES, *SPACE SHUTTLES,...
A rigid lightweight sandwich support structure, for the combustor chamber of a new generation liquid propellant rocket engine, was designed and fabricated using Polymer Matric Composite (PMC) facesheet on a Ti honeycomb or Carbon foam core. The facesheet consisted of high stiffness carbon fiber, M40JB, and high temperature Polyimides, such as PMR-11-50 and HFPE-II. Six different fiber architectures; 4HS woven fabric, uni-fabric, woven-uni hybrid, stitched woven fabric, stitched uni-fabric and...
Topics: NASA Technical Reports Server (NTRS), POLYMER MATRIX COMPOSITES, REINFORCING FIBERS, HYGRAL...
The report describes an investigation to evaluate a medium-duty aluminum honeycomb-core landing mat designed and fabricated by Goodyear Aerospace Corporation, Akron, Ohio, as a result of the Government request for proposal dated 6 May 1968. The medium-duty mat was a sandwich-type structure with a honeycomb core bonded by an epoxy film adhesive to aluminum top and bottom skins. Extruded aluminum edge connectors were also bonded with a similar adhesive to the top and bottom skins and to the core....
Topics: DTIC Archive, Carr, Gordon L, ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS, *LANDING...
A comprehensive development and verification test program has been established for the structure of the B-2707 airplane. It recognizes the more demanding usage and environment to which the airplane is subjected, and the use of relatively new structural materials and processes. Additionally, it recognizes the problems of contemporary airplanes and provides testing of proper magnitude and timing to preclude recurrence of similar problems on the SST. Structural areas of concern have been covered...
Topics: DTIC Archive, Donaldson, D R, BOEING CO SEATTLE WA SUPERSONIC TRANSPORT DIV, *AIRFRAMES, *JET...
The objectives of this program were to place polyimide matrix advanced composite processing technology on a production basis, and to demonstrate its acceptability for structural applications by fabrication and test of representative structure. Under this program polyimide matrix advanced composites were cured in a one shift autoclave operations (-8 hours) at 350 F and 200 psi maximum while maintaining epoxy matrix-type properties. These process parameters were confirmed by the successful...
Topics: DTIC Archive, Birchfield, Edwin B, MCDONNELL AIRCRAFT CO ST LOUIS MO, *COMPOSITE MATERIALS,...
Flight-test measurements of wingloads (shear, bending moment, and torque) were obtained by means of strain-gage bridges mounted on the exterior surface of a low-aspect-ratio, thin, swept wing which had a structural skin, full-depth honeycomb core, sandwich construction. Details concerning the strain-gage bridges, the calibration procedures used, and the flight-test results are presented along with some pressure measurements and theoretical calculations for comparison purposes.
Topics: NASA Technical Reports Server (NTRS), FLIGHT LOAD RECORDERS, LOW ASPECT RATIO WINGS, STRAIN GAGES,...
The nonlinear/inelastic response under inplane shear of a large variety of graphite-epoxy and boron-epoxy angle-ply laminates was tested. Their strength allowables were obtained and the mechanisms which govern their mode of failure were determined. Two types of specimens for the program were chosen, tested, and evaluated: shear panels stabilized by an aluminum honeycomb core and shear tubes. A modified biaxially compression/tension loaded picture frame was designed and utilized in the test...
Topics: NASA Technical Reports Server (NTRS), BORON-EPOXY COMPOSITES, GRAPHITE-EPOXY COMPOSITES, LAMINATES,...
Foil gage superalloys are candidate materials for use in structural and heat shield panels for reentry and hypersonic vehicles. Unlike the coated refractory metals, little attention has been given to the potential environmental effects that may contribute to changes in mechanical properties of foil gage superalloys as a result of the low-pressure and slow-cyclic exposure of a typical hypersonic flight. The objective of this program was to investigate and evaluate operative degradation...
Topics: DTIC Archive, Malik, Raj K, SOLAR TURBINES INTERNATIONAL SAN DIEGO CA, *HEAT SHIELDS, *NICKEL...
The moisture diffusion coefficients and solubilities of Advanced Enclosed Mast/Sensor (AEM/S) sandwich constituent materials of interest have been determined at 22, 35, and 50 deg C and at 80 percent relative humidity. Expressions for calculating the diffusion coefficients and solubilities for any temperature of interest to marine environments are provided. The objective of this study was to provide input data for finite element moisture diffusion analyses that permits one to predict the...
Topics: DTIC Archive, Augl, Joseph M., NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD, *COMPOSITE...
Two common concerns in the use of sandwich composite construction are the effects of low velocity impact and delamination upon structural failure. Finite element analysis of these events can provide a comprehensive time history of the resulting stress strain, displacement, and velocity at all points in a structure. The purpose of this research is to develop a finite element model of a sandwich composite and use this model to analyze the dynamic response of an unbalanced sandwich beam, a...
Topics: DTIC Archive, Wojcik, Gerald W., NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *IMPACT STRENGTH,...
Formulas and associated graphs for evaluating the effective elastic constants for a superplastically formed/diffusion bonded (SPF/DB) corrugated sandwich core, are presented. A comparison of structural stiffnesses of the sandwich core and a honeycomb core under conditions of equal sandwich core density was made. The stiffness in the thickness direction of the optimum SPF/DB corrugated core (that is, triangular truss core) is lower than that of the honeycomb core, and that the former has higher...
Topics: NASA Technical Reports Server (NTRS), DIFFUSION WELDING, ELASTIC PROPERTIES, SANDWICH STRUCTURES,...
A new impedance eduction procedure is validated by comparing the educed impedance spectrum to that of an older but well-tested eduction procedure. The older procedure requires the installation of a microphone array in the liner test section but the new procedure removes this requirement. A 12.7-mm stainless steel plate and a conventional liner consisting of a perforated plate bonded to a honeycomb core are tested. Test data is acquired from a grazing flow, impedance tube facility for a range of...
Topics: NASA Technical Reports Server (NTRS), ELECTRICAL IMPEDANCE, FREQUENCY RANGES, GRAZING FLOW, TEST...
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Jul 23, 2010
07/10
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NON
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Described is a laser Doppler velocimeter (LDV) which is capable of operating with a small focus diameter for analyzing fluid flows at low velocity with high spatial resolution, or with a larger focus diameter to measure fluid flows at higher velocities accurately. More particularly, this is an LDV in which a simple reversal of a lens pair will allow it to operate in the two focus diameter modes.
Topics: LARGE SPACE STRUCTURES, GRAPHITE, HONEYCOMB CORES, PIPES (TUBES), RODS, SPACE COMMERCIALIZATION,...
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May 27, 2011
05/11
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Ono, S.; Ennyu, A.; Najjar, R. G.; Bates, N
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A diagnostic model of the mean annual cycles of dissolved inorganic carbon (DIC) and oxygen below the mixed layer at the Bermuda Atlantic Time-series Study (BATS) site is presented and used to estimate organic carbon remineralization in the seasonal thermocline. The model includes lateral and vertical advection as well as vertical, diffusion. Very good agreement is found for the remineralization estimates based on oxygen and DIC. Net remineralization averaged from mid-spring to early fall is...
Topics: SANDWICH STRUCTURES, LOADS (FORCES), WRINKLING, DESIGN ANALYSIS, HONEYCOMB CORES, STRUCTURAL...
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Jun 13, 2011
06/11
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James, Mark A.; Dawicke, David S.; Brzowski, Matthew B.; Raju, Ivatury S.; Elliott, Kenny B.; Harris, Charles E
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Inspections of the Space Shuttle Main Engine revealed fatigue cracks growing from slots in the flow liner of the liquid hydrogen (LH2) feed lines. During flight, the flow liners experience complex loading induced by flow of LH2 and the resonance characteristics of the structure. The flow liners are made of Inconel 718 and had previously not been considered a fracture critical component. However, fatigue failure of a flow liner could have catastrophic effect on the Shuttle engines. A fracture...
Topics: HONEYCOMB CORES, ACOUSTIC VELOCITY, ELECTRICAL IMPEDANCE, BROADBAND, AIRCRAFT ENGINES, LININGS,...
