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  • Other Sources  (729)
  • AERODYNAMICS  (546)
  • COMPOSITE MATERIALS  (183)
  • Cell & Developmental Biology
  • Inorganic Chemistry
  • 1985-1989  (729)
  • 1940-1944
  • 1988  (729)
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  • 1985-1989  (729)
  • 1940-1944
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  • 1
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    Hygrothermal and strain-rate effects on properties of graphite/epoxy composites (1988)
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    Publication Date: 2011-08-19
    Description: The combined effects of moisture (M), temperature (T), and strain rate (SR) on the properties of the unidirectional graphite/epoxy composite AS4/3501-6 are investigated experimentally. Longitudinal tensile, in-plane shear, and transverse tensile specimens with moisture content 0 or 1 percent were characterized using standard mechanical tests and the techniques described by Yaniv et al. (1987) at temperatures 23-128 C and strain rates from 5 x 10 to the -6th/sec to 5/sec. The results are presented in graphs and discussed in detail. The longitudinal properties of the composite were found to be generally unaffected by changes in the parameters, whereas transverse and interlaminar properties decreased with increasing T and M at constant SR and the transverse and in-plane shear moduli increased with SR. A time-T-M equivalence principle is used to derive master curves for all the matrix-dominated properties, expressed in terms of a two-variable shift function.
    Keywords: COMPOSITE MATERIALS
    Type: ASME, Transactions, Journal of Engineering Materials and Technology (ISSN 0094-4289); 110; 169-173
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  • 2
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    Thermally induced twist in graphite-epoxy tubes (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: This paper discusses an analytical and experimental study to investigate the thermally induced twist in laminated angle-ply graphite-epoxy tubes. Attention is focused on balanced laminates which, contrary to intuition, exhibit twist when the temperature is changed. The twisting is due to the fact that a lamina with ( a + phi) orientation and a lamina with (a - phi) orientation must be at slightly different radial positions in the twist. The lamina with the greater radial position determines the sense of the twist. Classical lamination theory does not predict this phenomenon, and so as more sophisticated theory must be employed. This paper outlines such as theory, which is based on an generalized plane-deformation elasticity analysis, and presents experimental data to confirm the predictions of the theory. A brief description of the experimental apparatus and procedure used to measure twist is presented.
    Keywords: COMPOSITE MATERIALS
    Type: ASME, Transactions, Journal of Engineering Materials and Technology (ISSN 0094-4289); 110; 83-88
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  • 3
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    Force and pressure study of thick cambered/twisted 58 deg delta wings (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 69-75
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  • 4
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    Progress in analysis and prediction of dynamic stall (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 6-17
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  • 5
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    Fibre-matrix bond strength studies of glass, ceramic, and metal matrix composites (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: An indentation test technique for compressively loading the ends of individual fibers to produce debonding has been applied to metal, glass, and glass-ceramic matrix composites; bond strength values at debond initiation are calculated using a finite-element model. Results are correlated with composite longitudinal and interlaminar shear behavior for carbon and Nicalon fiber-reinforced glasses and glass-ceramics including the effects of matrix modifications, processing conditions, and high-temperature oxidation embrittlement. The data indicate that significant bonding to improve off-axis and shear properties can be tolerated before the longitudinal behavior becomes brittle. Residual stress and other mechanical bonding effects are important, but improved analyses and multiaxial interfacial failure criteria are needed to adequately interpret bond strength data in terms of composite performance.
    Keywords: COMPOSITE MATERIALS
    Type: Journal of Materials Science (ISSN 0022-2461); 23; 311-328
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  • 6
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    Space radiation effects on poly(aryl-ether-ketone) thin films and composites (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The purpose of this study was to assess the space durability of poly(aryl-ether-ketone) (PEEK) in the forms of films and graphite fiber reinforced composites. The influence of the film's crystallinity on electron radiation stability was evaluated using X-ray diffraction, DSC, FTIR, and mechanical property tests. The mechanical properties of the composites material were evaluated after electron radiation and after electron radiation followed by thermal cycling simulating 30 years in geosynchronous orbit.
    Keywords: COMPOSITE MATERIALS
    Type: SAMPE Quarterly (ISSN 0036-0821); 19; 19-26
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  • 7
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    High temperature properties of ceramic fibers and insulations for thermal protection of atmospheric entry and hypersonic cruise vehicles (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Multilayer insulations (MIs) which will operate in the 500 to 1000 C temperature range are being considered for possible applications on aerospace vehicles subject to convective and radiative heating during atmospheric entry. The insulations described consist of ceramic fibers, insulations, and metal foils quilted together with ceramic thread. As these types of insulations have highly anisotropic properties, the total heat transfer characteristics must be determined. Data are presented on the thermal diffusivity and thermal conductivity of four types of MIs and are compared to the baseline Advanced Flexible Reusable Surface Insulation currently used on the Space Shuttle Orbiter. In addition, the high temperature properties of the fibers used in these MIs are discussed. The fibers investigated included silica and three types of aluminoborosilicate (ABS). Static tension tests were performed at temperatures up to 1200 C and the ultimate strain, tensile strength, and tensile modulus of single fibers were determined.
    Keywords: COMPOSITE MATERIALS
    Type: SAMPE Quarterly (ISSN 0036-0821); 19; 8-18
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  • 8
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    Thermal cycling of tungsten-fibre-reinforced superalloy composites (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The thermal cycling of a tungsten-fiber-reinforced superalloy (TFRS) composite is typical of its application in high-temperature engine environments. The mismatch in thermal expansion coefficients between fiber and matrix causes substantial longitudinal (0 deg) stresses in the composite, which can produce inelastic damage-producing matrix strains. The case of thermal fatigue is explored as a "worst case" of the possible matrix damage, in comparison with specimens which are also mechanically loaded in tension. The thermally generated cyclic stresses and the attendant matrix plasticity may be estimated using a nonlinear finite-element program, by proposing a physical analog to the micromechanics equations. A damage metric for the matrix is proposed using the Coffin-Manson criterion, which metric can facilitate comparisons of damage among different candidate materials, and also comparisons for a given material subjected to different temperature cycles. An experimental program was carried out for thermal cycling of a 37 vol pct TFRS composite to different maximum temperatures. The results confirm the prediction that thermal cycling produces matrix degradation and composite strength reduction, which become more pronounced with increasing maximum cyclic temperature. The strength of the fiber is shown to be identical for the as-fabricated and thermally cycled specimens, suggesting that the reduction in composite strength is due to the loss of matrix contribution and also to notching effects of the matrix voids on the fiber.
    Keywords: COMPOSITE MATERIALS
    Type: Journal of Materials Science (ISSN 0022-2461); 23; 713-717
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  • 9
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    Two-component LDV investigation of three-dimensional shock/turbulent boundary-layer interactions (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 26; 52-56
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  • 10
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    Unsteady transonic flow simulation on a full-span-wing-body configuration (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 26; 1450-145
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  • 11
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    Damage initiation and growth in fiber-reinforced MMCs (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: On the basis of the simplifying assumption of equivalent constituent strain rates in the absence of damage, a strain-based failure criterion can be applied to the phenomena of damage-initiation and growth in fiber-reinforced MMCs to ascertain when and where the initial damage will occur. The failure modes fall into four categories, depending on the relative fatigue behavior of the reinforcing fibers and their matrix. Attention is given to experimental results illustrating current understanding of fiber-dominated damage, self-similar fatigue damage growth, and fiber/matrix interface failures, for such MMCs as B/Al alloy, SiC/Al alloy, and SiC/Ti-15-3 alloy.
    Keywords: COMPOSITE MATERIALS
    Type: Journal of Metals (ISSN 0148-6608); 40; 58-63
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  • 12
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    Unsteady transonic aerodynamics and aeroelastic calculations at low-supersonic freestreams (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A computational procedure is presented to simulate transonic unsteady flows and corresponding aeroelasticity of wings at low-supersonic freestreams. The flow is modeled by using the transonic small-perturbation theory. The structural equations of motions are modeled using modal equations of motion directly coupled with aerodynamics. Supersonic freestreams are simulated by properly accounting for the boundary conditions based on pressure waves along the flow characteristics in streamwise planes. The flow equations are solved using the time-accurate, alternating-direction implicit finite-difference scheme. The coupled aeroelastic equations of motion are solved by an integration procedure based on the time-accurate, linear-acceleration method. The flow modeling is verified by comparing calculations with experiments for both steady and unsteady flows at supersonic freestreams. The unsteady computations are made for oscillating wings. Comparisons of computed results with experiments show good agreement. Aeroelastic responses are computed for a rectangular wing at Mach numbers ranging from subtransonic to upper-transonic (supersonic) freestreams. The extension of the transonic dip into the upper transonic regime is illustrated.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 955-961
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  • 13
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    Further comparisons of interactive boundary-layer and thin-layer Navier-Stokes procedures (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 897-903
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  • 14
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    Transonic Navier-Stokes solutions for a fighter-like configuration (1988)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 875-881
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  • 15
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    Microstructural evolution on crystallizing the glassy phase in a 6 weight percent Y2O3-Si3N4 ceramic (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: X-ray diffraction and analytical electron microscopy have been used to study the crystallization of the grain-boundary glass in a 6 wt pct Y2O3-Si3N4 ceramic. Upon crystallization, high densities of dislocations formed in the Si3N4 grains and remained after 5 h at temperature. However, prolonged holds at the crystallization temperature effectively annealed out the dislocations. Other features present in the microstructure are characterized.
    Keywords: COMPOSITE MATERIALS
    Type: Ceramic Engineering and Science Proceedings (ISSN 0196-6219); 9; 1355-136
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  • 16
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    An experimental investigation of the fracture behavior of thick, notched laminated composites (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The fracture of high-modulus fiber-reinforced graphite/epoxy laminates with machined crack-like notches is discussed. An experimental program was conducted, in which stacking sequence,laminate thickness, notch size, and specimen configuration have been investigated. This research has led to the fundamental observation that heterogeneity significantly effects the fracture of thin laminates but has a relatively insignificant effect on the fracture of thick laminates. The results of this program are reviewed with the emphasis on the notch sensitivity and design of thick laminates.
    Keywords: COMPOSITE MATERIALS
    Type: Journal of the Mechanical Behavior of Materials (ISSN 0334-8938); 1; 1-4,; 55-79
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  • 17
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    Analysis of delamination growth from matrix cracks in laminates subjected to bending loads (1988)
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    Publication Date: 2011-08-19
    Description: A major source of delamination damage in laminated composite materials is from low-velocity impact. In thin composite laminates under point loads, matrix cracks develop first in the plies, and delaminations then grow from these cracks at the ply interfaces. The purpose of this study was to quantify the combined effects of bending and transverse shear loads on delamination initiation from matrix cracks. Graphite-epoxy laminates with 90 deg plies on the outside were used to provide a two-dimensional simulation of the damage due to low-velocity impact. Three plate bending problems were considered: a 4-point bending, 3-point bending, and an end-clamped center-loaded plate. Under bending, a matrix crack will form on the tension side of the laminate, through the outer 90 deg plies and parallel to the fibers. Delaminations will then grow in the interface between the cracked 90 deg ply and the next adjacent ply. Laminate plate theory was used to derive simple equations relating the total strain energy release rate, G, associated with the delamination growth from a 90 deg ply crack to the applied bending load and laminate stiffness properties. Three different lay-ups were tested and results compared. Test results verified that the delamination always formed at the interface between the cracked 90 deg ply and the next adjacent ply. Calculated values for total G sub c from the analysis showed good agreement for all configurations. The analysis was able to predict the delamination onset load for the cases considered. The result indicated that the opening mode component (Mode I) for delamination growth from a matrix crack may be much larger than the component due to interlaminar shear (Mode II).
    Keywords: COMPOSITE MATERIALS
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  • 18
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    Experimental aerodynamic characteristics of an NACA 0012 airfoil with simulated glaze ice (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The effect of a simulated glaze-ice accretion on the aerodynamic performance of a NACA 0012 airfoil was studied experimentally. Two ice shapes were tested: one from an experimentally measured accretion, and one from an accretion predicted using a computer model given the same icing conditions. Lift, drag, and pitching moment were measured for the airfoil with both smooth and rough ice shapes. The ice shapes caused large lift and drag penalties, primarily due to large separation bubbles. Surface pressure distributions clearly showed the regions of separated flow. The aerodynamic performance of the two shapes compared well at positive, but not negative, angles of attack.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 849-854
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  • 19
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    Grid generation and inviscid flow computation about a cranked-winged airplane geometry (1988)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 820-826
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  • 20
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    Thermo-oxidative stability studies of Celion 6000/PMR-15 unidirectional composites, PMR-15, and Celion 6000 fiber (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Experimental results on the influence of the thermooxidative resistance characteristics of the fiber and matrix resin on the thermal stability of isothermally aged Celion 6000/PMR-15 matrix resin composites are presented. SEM studies reveal that extreme oxidative erosion of the graphite fiber occurs at elevated temperatures in the presence of the polyimide matrix. The activation energy of oxidation of the composite was shown to be greater than those of the fiber and the matrix resin.
    Keywords: COMPOSITE MATERIALS
    Type: Journal of Composite Materials (ISSN 0021-9983); 22; 966-985
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  • 21
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    The strength of laminated composite materials under repeated impact loading (1988)
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    Publication Date: 2011-08-19
    Description: When low velocity and energy impact is exerted on a laminated composite material, in a perpendicular direction to the plane of the laminate, invisible damage may develop. It is shown analytically and experimentally that the invisible damage occurs during the first stage of contact between the impactor and the laminate and is a result of the contact stresses. However, the residual flexural strength changes only slightly, because it depends mainly on the outer layers, and these remain undamaged. Repeated impact intensifies the damage inside the laminate and causes larger bending under equivalent impact load. Finally, when the damage is most severe, even though it is still invisible, the laminate fails because of bending on the tension side. If the repeated impact is halted before final fracture occurs the residual strength and modulus would decrease by a certain amount.
    Keywords: COMPOSITE MATERIALS
    Type: Journal of Composites Technology and Research (ISSN 0885-6804); 10; 74-79
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  • 22
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    Effects of surface roughness on two Shuttle Orbiter models (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 349-354
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  • 23
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    Thermal environment of transatmospheric vehicles (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 355-363
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  • 24
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    Unsteady low-speed aerodynamic model for complete aircraft configurations (1988)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 302-310
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  • 25
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    Passive venting system for modifying cavity flowfields at supersonic speeds (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The drag of airfoils in transonic flow can be reduced through the use of a passive venting system that employs a porous plate for part of the airfoil upper surface with a vent chamber underneath the porous plate Attention is given to the results obtained with a wind tunnel model employing such a porous floor system. This passive venting system has been used to extend the length/height value before the onset of high drag-producing closed cavity flow at supersonic speeds.
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 26; 374-376
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  • 26
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    Vortex shedding in high-speed compressor blade wakes (1988)
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    Publication Date: 2011-08-19
    Description: The wakes of highly loaded compressor blades are generally considered to be turbulent flows. Recent work has suggested that the blade wakes are dominated by a vortex streetlike structure. The experimental evidence supporting the wake vortex structure is reviewed. This structure is shown to redistribute thermal energy within the flowfield. The effect of the wake structure on conventional aerodynamic measurements of compressor performance is noted. A two-dimensional, time-accurate, viscous numerical simulation of the flow exhibits both vortex shedding in the wake and a lower-frequency flow instability that modulates the shedding. The numerical results are shown to agree quite well with the measurement from transonic compressor rotors.
    Keywords: AERODYNAMICS
    Type: Journal of Propulsion and Power (ISSN 0748-4658); 4; 236-244
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  • 27
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    Prediction of oscillating thick cambered aerofoil aerodynamics by a locally analytic method (1988)
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    Publication Date: 2011-08-19
    Description: The effects of mean-flow incidence, airfoil camber, and airfoil thickness on the incompressible aerodynamics of an oscillating airfoil are investigated theoretically, developing and applying a first-order FEM based on locally analytical solutions (LASs). Laplace equations are used to describe the steady and unsteady harmonic velocity potentials; a body-fitted computational grid is employed; grid-element solutions for both potentials are determined using a numerical LAS method; and the LASs are then assembled to obtain a complete solution. Results for a series of flat-plate and Joukowski airfoils are presented in extensive graphs and discussed in detail.
    Keywords: AERODYNAMICS
    Type: International Journal for Numerical Methods in Fluids (ISSN 0271-2091); 8; 913-931
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  • 28
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    Multigrid solution of the two-dimensional Euler equations on unstructured triangular meshes (1988)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 26; 824-831
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  • 29
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    Multigrid acceleration of the flux-split Euler equations (1988)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 26; 649-654
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  • 30
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    Vortical flow over an elliptical-body missile at high angles of attack (1988)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4650); 25; 24-30
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  • 31
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    Theory of idealized two-dimensional ballute in Newtonian hypersonic flow (1988)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4650); 25; 217-224
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  • 32
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    Impact induced stresses, strains, and delaminations in composite plates (1988)
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    Publication Date: 2011-08-19
    Description: A method is presented for calculating the locations and sizes of delaminations which occur in a rectangular, fiber reinforced composite plate subjected to nonpenetrating (low velocity) impact of a solid object. The plate may be simply supported or clamped along its edges. In-plane loads or in-plane strains may be imposed on the plate during the impact. The method includes two steps. First, the stresses and strains in the plate are calculated by a three-dimensional, transient finite element method using 8-node brick elements with incompatible modes. Second, the locations, lengths, and widths of delaminations inside the plate are predicted by means of a proposed failure criterion, which is based on the concept of dimensional analysis. The finite element method and the failure criterion were implemented by a computer code which can be used to calculate the impactor position and velocity, the displacements of the plate, the stresses and strains inside the plate during the impact, and the locations and dimensions of the delaminations after the impact. Parametric studies were performed to illustrate the information which can be generated by the computer code.
    Keywords: COMPOSITE MATERIALS
    Type: Journal of Composite Materials (ISSN 0021-9983); 22; 533-560
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  • 33
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    Non-isothermal crystallization of poly(etheretherketone) aromatic polymer composite (1988)
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    Publication Date: 2011-08-19
    Description: The nonisothermal crystallization kinetics of PEEK APC-2 and of 450G neat resin PEEK material were compared using a differential scanning calorimeter to monitor heat flow during crystallization; the effects of cooling rate on the crystallization temperature, the degree of crystallinity, and the conversion rate were investigated. A modified Avrami (1940) analysis was used to describe nonisothermal crystallization kinetics. It was found that, compared with the 450G neat resin PEEK, the nonisothermal crystallization of the PEEK APC-2 composite is characterized by higher initiation temperature, higher heat flow maximum temperature, and greater relative conversion by primary processes.
    Keywords: COMPOSITE MATERIALS
    Type: Polymer Composites (ISSN 0272-8397); 9; 271-279
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  • 34
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    Incompressible Navier-Stokes computations for a round-edged double-delta wing (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 675
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  • 35
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    Transonic characteristics of a humped airfoil (1988)
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 673
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    Polyimide/metal composite films via in situ decomposition of inorganic additives - Soluble polyimide versus polyimide precursor (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Polyimide-metal oxide (Co3O4 or CuO) composite films have been prepared via in situ thermal decomposition of cobalt (II) chloride or bis(trifluoroacetylacetonato)copper(II). A soluble polyimide (XU-218) and its corresponding prepolymer (polyamide acid) were individually employed as the reaction matrix. The resulting composites exhibited a greater metal oxide concentration at the air interface with polyamide acid as the reaction matrix. The water of imidization that is released during the concurrent polyamide acid cure and additive decomposition is believed to promote metal migration and oxide formation. In contrast, XU-218 doped with either HAuCl4.3H2O or AgNO3 yields surface gold or silver when thermolyzed (300 C).
    Keywords: COMPOSITE MATERIALS
    Type: Journal of Materials Research (ISSN 0884-2914); 3; 996-1001
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  • 37
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    Prediction of incidence effects on oscillating airfoil aerodynamics by a locally analytical method (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A complete mathematical model is formulated to analyze the effects of mean-flow incidence angle on the unsteady aerodynamics of an oscillating airfoil in an incompressible flow field. A velocity potential formulation is utilized. The steady flow is independent of the unsteady flow field but coupled to it through the boundary conditions on the oscillating airfoil. The numerical solution technique for both the steady and unsteady flow fields is based on a locally analytical method. The flow model and solution method are then verified through the excellent correlation obtained with the Theodorsen oscillating-flat-plate and Sears transverse-gust classical solutions. The effects of mean flow incidence on the steady and oscillating airfoil aerodynamics are then investigated.
    Keywords: AERODYNAMICS
    Type: International Journal for Numerical Methods in Engineering (ISSN 0029-5981); 26; 2227-223
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  • 38
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    Efficient algorithm for solution of the unsteady transonic small-disturbance equation (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 598-605
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  • 39
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    Study of multibody aerodynamic interference at transonic Mach numbers (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 26; 553-560
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  • 40
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    A thin-layer solution of the flow about a prolate spheroid (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Computational results are presented for the transitional or turbulent flow about a prolate spheroid, at alpha = 10 deg or 30 deg, correspondingly, using an implicit, approximately factored, partially flux-split algorithm, based on the thin-layer equations. The computed flow field is in good agreement with available experimental data.
    Keywords: AERODYNAMICS
    Type: Zeitschrift fuer Flugwissenschaften und Weltraumforschung (ISSN 0342-068X); 12; 173-180
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  • 41
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    Measurements of matrix cracking and delamination caused by impact on composite plates (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Tests were performed measuring the locations and extents of delaminations and matrix crackings in 3-in. by 3-in. Fiberite T300/934 graphite/epoxy plates impacted by 1/2-in. diameter aluminum spheres. Plates with six ply orientations were tested. The impactor speeds ranged from 700 to 1300 in/sec. The plates were inspected by C-scan both before and after impact. The plates were also dissected after impact and examined visually for damage. In addition, the longitudinal and transverse tensile, compressive, and shear properties of the material were measured.
    Keywords: COMPOSITE MATERIALS
    Type: Journal of Composite Materials (ISSN 0021-9983); 22; 518-532
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  • 42
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    Turbulent viscous drag reduction with thin-element riblets (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Thin-element riblets for aircraft aerodynamic surface turbulent viscous drag reduction are presently found to be as effective as symmetric V-grooves in this role, while possessing a greater range of admissible spacings. The thin-element geometry shows the qualitatively predictable influence of independent riblet height and spacing variations. The evidence for more than one drag-reduction mechanism in thin-element riblets is found to be inconclusive.
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 26; 496-498
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  • 43
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    Rarefaction effects for hypersonic re-entry flow (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 26; 392
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  • 44
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    An overview of hypersonic aerothermodynamics (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: This paper briefly reviews some national studies and new programs concerning hypersonic flight. The flight environment that will be encountered by this new class of hypersonic vehicles is described, and the fluid-dynamic and chemical phenomena that occur in hypersonic flight are examined. Ground-based facilities are briefly described, and their use in helping to validate the codes is examined.
    Keywords: AERODYNAMICS
    Type: Communications in Applied Numerical Methods (ISSN 0748-8025); 4; 319-325
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  • 45
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    Entropy and vorticity corrections for transonic flows (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Different models for inviscid transonic flows are examined. The common assumptions that the flow is isentropic and irrotational are critically evaluated. Entropy and vorticity correction procedures for potential and stream function formulations are presented, together with the details of the treatment of shocks and wakes, and drag and lift calculations. The non-uniqueness problem of the potential formulation is studied using different artificial viscosity forms. Numerical results are compared with Euler solutions.
    Keywords: AERODYNAMICS
    Type: International Journal for Numerical Methods in Fluids (ISSN 0271-2091); 8; 31-53
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  • 46
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    Drag measurements on a laminar flow body of revolution in Langley's 13 inch magnetic suspension and balance system (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Low-speed wind tunnel drag force measurements were taken on a laminar flow body of revolution free of support interference. This body was tested at zero incidence in the NASA Langley 13 inch Magnetic Suspension and Balance System (MSBS). The primary objective of these tests was to substantiate the drag force measuring capabilities of the 13 inch MSBS. A secondary objective was to obtain support interference free drag measurements on an axisymmetric body of interest. Both objectives were met. The drag force calibrations and wind-on repeatability data provide a means of assessing the drag force measuring capabilities of the 13 inch MSBS. The measured drag coefficients for this body are of interest to researchers actively involved in designing minimum drag fuselage shapes. Additional investigations included: the effects of fixing transition; the effects of fins installed in the tail; surface flow visualizations using both liquid crystals and oil flow; and base pressure measurements using a one-channel telemetry system. Two drag prediction codes were used to assess their usefulness in estimating overall body drag. These theoretical results did not compare well with the measured values because of the following: incorrect or non-existent modeling of a laminar separation bubble on the body and incorrect of non-existent estimates of base pressure drag.
    Keywords: AERODYNAMICS
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  • 47
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    The viscoplastic behavior of SCS6/Ti-15-3 metal matrix composite materials at elevated temperatures (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Titanium-based metal matrix composite materials (MMC'S) are being considered for use in the National Aerospace Plane. It is expected that these materials will be subjected to temperatures ranging up to about 820 C (1500 F). The present study was a preliminary investigation intended to quantify the level of viscoplastic behavior exhibited by SCS6/Ti-15-3 MMC's at elevated temperatures. The study consisted of a series of uniaxial creep/creep recovery tests. These tests were conducted in air at a temperature of 535 C (1000 F). Three distinct types of specimens were tested: Ti-15-3 heat matrix specimens (O2/plus or minus 45) sub s composite specimens, and (90 sub 2/plus or minus 45) sub s composite specimens. Tensile loads were applied to the specimens using a lever-arm creep frame equipped with a high temperature furnace. Specimen creep stains were monitored using an LVDT-based extensometer.
    Keywords: COMPOSITE MATERIALS
    Type: Hampton Inst., NASA/American Society for Engineering Ed; Hampton Inst., NASA(
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  • 48
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    Optimization of slender wings for center-of-pressure shift due to change in Mach number (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: It is observed that the center of pressure on a wing shifts as the Mach number is changed. Such shifts are in general undesirable and are sometimes compensated for by actively shifting the center of gravity of the aircraft or by using active stability controls. To avoid this complication, it is desirable to design the wings of a high speed aircraft so as to minimize the extent of the center-of-pressure shifts. This, together with a desire to minimize the center-of-pressure shifts in missile control surfaces, provides the motivation for this project. There are many design parameters which affect center-of-pressure shifts, but it is expected that the largest effects are due to the wing planform. Thus, for the sake of simplicity, this study is confined to an investigation of thin, flat, (i.e., no camber or twist), relatively slender, pointed wings flying at a small angle of attack. Once the dependence of the center of pressure on planform and Mach number is understood, we can expect to investigate the sensitivity of the center-of-pressure shifts to various other parameters.
    Keywords: AERODYNAMICS
    Type: Hampton Inst., NASA/American Society for Engineering Educ; Hampton Inst., NASA(
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  • 49
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    A study on the thermal and moisture influences on the free-edge delamination of laminated composites (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A simple delamination analysis method is presented here. It is based on a shear-type deformation theory and includes hygrothermal effects. These environmental conditions are applied to the strain energy release rate and interlaminar shear stresses. The method is applied to mixed mode edge delamination specimens made of T300/5208 graphite/epoxy material. Residual thermal and moisture stresses significantly influenced the strain energy release rate and interlaminar stresses. Both experienced large increases when thermal conditions were added to the mechanical strains. These effects were alleviated when moisture stresses were included. Thermal effects on the interlaminar shear stress and total energy release rate were totally alleviated for the same specific moisture content. Moreover, the value of the moisture content was not significantly affected by the stacking sequence for the laminates considered.
    Keywords: COMPOSITE MATERIALS
    Type: Analysis of Delamination Related Fracture Processes in Composites; 93 p
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  • 50
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    Introduction to the analysis of delamination related fracture processes in composites (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This research concerns the analysis and prediction of delamination damage that occurs in composite structures on the sublaminate scale - that is, the scale of individual plies or groups of plies. The objective was to develop analytical models for fixed-mode delamination in composites. These include: (1) the influence of residual thermal and moisture strains; (2) local or transverse crack tip delamination originating at the tip of transverse matrix cracks; and (3) delamination in tapered composite under tensile loading. Computer codes based on the analytical models were developed and comparisons of predictions with available experimental and analytical results in the literature were performed.
    Keywords: COMPOSITE MATERIALS
    Type: Analysis of Delamination Related Fracture Processes in Composites; 22 p
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  • 51
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    Approaches to non-linear aerodynamic analysis and design (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Within the last two decades, there has been increasing emphasis on developing more sophisticated computational fluid dynamics (CFD) methods to handle a wide range of problems of interest to the aerospace community. The comprehensive picture of the status of CFD development and capability as well as an assessment of requirements and future directions are given. An independent review and assessment was also carried out by the author as part of the current assignment and the results are outlined herein.
    Keywords: AERODYNAMICS
    Type: Hampton Inst., NASA/American Society for Engineering Educ; Hampton Inst., NASA(
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  • 52
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    Strain energy release rate, interlaminar stresses, and 3-D transformation of stiffnesses (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: In this analysis, a delamination between the belt and core sections is assumed to grow parallel to the belt direction in the tapered and uniform sections. These delaminations in each section are denoted by a and b respectively. The core section in the taper portion is modeled by two equivalent sublaminates. The stiffness properties are smeared to obtain effective cracked and uncracked stiffnesses which are designated A (u) and A (c). These stiffnesses change from one ply drop group to another with crack growth a by experiencing a sudden change at discrete locations. Therefore, A (u) and A (c) can be represented in three consecutive regions.
    Keywords: COMPOSITE MATERIALS
    Type: Analysis of Delamination Related Fracture Processes in Composites; 17 p
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  • 53
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    Fracture analysis of local delaminations in laminated composites (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A shear deformation model was developed to analyze local delaminations growing from transverse cracks in 90 degree plies located around the mid plane of symmetric laminates. The predictions of the model agree reasonably with experimental data from T300/934 graphite epoxy laminates. The predicted behavior is such that, in combination with an edge delamination model, the critical loads can be predicted accurately in the range of n from .5 to 8.
    Keywords: COMPOSITE MATERIALS
    Type: Analysis of Delamination Related Fracture Processes in Composites; 41 p
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    Computational unsteady aerodynamics for lifting surfaces (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Two dimensional problems are solved using numerical techniques. Navier-Stokes equations are studied both in the vorticity-stream function formulation which appears to be the optimal choice for two dimensional problems, using a storage approach, and in the velocity pressure formulation which minimizes the number of unknowns in three dimensional problems. Analysis shows that compact centered conservative second order schemes for the vorticity equation are the most robust for high Reynolds number flows. Serious difficulties remain in the choice of turbulent models, to keep reasonable CPU efficiency.
    Keywords: AERODYNAMICS
    Type: VKI, Unsteady Aerodynamics, Volume 2; 120 p
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    CFD application to supersonic/hypersonic inlet airframe integration (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Supersonic external compression inlets are introduced, and the computational fluid dynamics (CFD) codes and tests needed to study flow associated with these inlets are outlined. Normal shock wave turbulent boundary layer interaction is discussed. Boundary layer control is considered. Glancing sidewall shock interaction is treated. The CFD validation of hypersonic inlet configurations is explained. Scramjet inlet modules are shown.
    Keywords: AERODYNAMICS
    Type: VKI, Intake Aerodynamics, Volume 2; 62 p
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    CFD application to subsonic inlet airframe integration (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The fluid dynamics of curved diffuser duct flows of military aircraft is discussed. Three-dimensional parabolized Navier-Stokes analysis, and experiment techniques are reviewed. Flow measurements and pressure distributions are shown. Velocity vectors, and the effects of vortex generators are considered.
    Keywords: AERODYNAMICS
    Type: VKI, Intake Aerodynamics, Volume 2; 59 p
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  • 57
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    Computational methods for inlet airframe integration (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Fundamental equations encountered in computational fluid dynamics (CFD), and analyses used for internal flow are introduced. Irrotational flow; Euler equations; boundary layers; parabolized Navier-Stokes equations; and time averaged Navier-Stokes equations are treated. Assumptions made and solution methods are outlined, with examples. The overall status of CFD in propulsion is indicated.
    Keywords: AERODYNAMICS
    Type: VKI, Intake Aerodynamics, Volume 2; 43 p
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  • 58
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    Numerical investigation of a jet in ground effect using the fortified Navier-Stokes scheme (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: One of the flows inherent in VSTOL operations, the jet in ground effect with a crossflow, is studied using the Fortified Navier-Stokes (FNS) scheme. Through comparison of the simulation results and the experimental data, and through the variation of the flow parameters (in the simulation) a number of interesting characteristics of the flow have been observed. For example, it appears that the forward penetration of the ground vortex is a strong inverse function of the level of mixing in the ground vortex. Also, an effort has been made to isolate issues which require additional work in order to improve the numerical simulation of the jet in ground effect flow. The FNS approach simplifies the simulation of a single jet in ground effect, but it will be even more effective in applications to more complex topologies.
    Keywords: AERODYNAMICS
    Type: The 1987 Ground Vortex Workshop; p 191-206
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  • 59
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    F-15 SMTD low speed jet effects wind tunnel test results (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Key results from low speed wind tunnel testing of the F-15 STOL and Maneuver Technology Demonstrator (SMDT) with thrust reversers are presented. Longitudinally, the largest induced increments in the stability and control occur at landing gear height. These generally reflect an induced lift loss and a nose-up pitching moment, and vary with sideslip. Directional stability is reduced at landing gear height with full reverse thrust. Nonlinearities in the horizontal tail effectiveness are found in free air and at landing gear height.
    Keywords: AERODYNAMICS
    Type: NASA, Ames Research Center, The 1987 Ground Vortex Workshop; p 91-119
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    An assessment of ground effects determined by static and dynamic testing techniques (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A new testing technique was developed wherein the rate of descent can be included as a parameter in ground effects investigations. This technique simulates the rate of descent by horizontal motion of a model over an inclined ground board in the Langley Vortex Research Facility (VRF) During initial evaluations of the technique, dynamic ground effects data were obtained over the inclined ground board, steady state ground effects data were obtained over a flat portion of the ground board, and the results were compared to conventional static wind tunnel ground effect data both with and without a moving belt ground plane simulation. Initial testing and analysis led to the following conclusions: the moving belt ground plane had little effect on static ground effects for the configurations tested unless thrust reversers were employed; in general, rate-of-descent reduced ground effects to the point that for reversed thrust cases an expected loss of lift due to ground effects was eliminated at approach conditions; and, in general, the steady state results from the VRF matched static results obtained from the wind tunnel once the flow field stabilized over the flat portion of the ground board.
    Keywords: AERODYNAMICS
    Type: NASA, Ames Research Center, The 1987 Ground Vortex Workshop; p 121-146
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    Summary of an experimental investigation on the ground vortex (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The results of an experimental investigation into the position and characteristics of the ground vortex are summarized. A 48-inch wind tunnel was modified to create a testing environment suitable for the ground vortex study. Flow visualization was used to document the jet-crossflow interaction and a two-component Laser Doppler Velocimeter (LDV) was used to survey the flowfield in detail. Measurements of the ground vortex characteristics and location as a function of freestream-to-jet velocity ratio, jet height, pressure gradient and upstream boundary layer thickness were obtained.
    Keywords: AERODYNAMICS
    Type: NASA, Ames Research Center, The 1987 Ground Vortex Workshop; p 39-60
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  • 62
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    Ground vortex flow field investigation (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Flow field investigations were conducted at the NASA Ames-Dryden Flow Visualization Facility (water tunnel) to investigate the ground effect produced by the impingement of jets from aircraft nozzles on a ground board in a STOL operation. Effects on the overall flow field with both a stationary and a moving ground board were photographed and compared with similar data found in other references. Nozzle jet impingement angles, nozzle and inlet interaction, side-by-side nozzles, nozzles in tandem, and nozzles and inlets mounted on a flat plate model were investigated. Results show that the wall jet that generates the ground effect is unsteady and the boundary between the ground vortex flow field and the free-stream flow is unsteady. Additionally, the forward projection of the ground vortex flow field with a moving ground board is one-third less than that measured over a fixed ground board. Results also showed that inlets did not alter the ground vortex flow field.
    Keywords: AERODYNAMICS
    Type: The 1987 Ground Vortex Workshop; p 61-90
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    The characteristics of the ground vortex and its effect on the aerodynamics of the STOL configuration (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The interaction of the free stream velocity on the wall jet formed by the impingement of deflected engine thrust results in a rolled up vortex which exerts sizable forces on a short takeoff (STOL) airplane configuration. Some data suggest that the boundary layer under the free stream ahead of the configuration may be important in determining the extent of the travel of the wall jet into the oncoming stream. Here, early studies of the ground vortex are examined, and those results are compared to some later data obtained with moving a model over a fixed ground board. The effect of the ground vortex on the aerodynamic characteristics are discussed.
    Keywords: AERODYNAMICS
    Type: The 1987 Ground Vortex Workshop; p 1-38
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    Ceramic matrix composites in simulated SSME environments (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Future Space Shuttle Main Engine (SSME)-type rocket engines can benefit from the use of fiber-reinforced ceramix matrix composites (FRCMC). Ceramics reinforced with long continuous fibers exhibit improved tolerance to severe thermomechanical and environmental exposures. An in-house NASA-Lewis program to evaluate the durability of FRCMC in simulated SSME environments is described. Primary tests involve multiple (one second) exposures of FRCMC specimens in a hydrogen/oxygen rocket test rig. This rig generates surface heating rates of 1000 to 2500 C/second. The FRCMC durability evaluation involves measurement of retained strength as a function of thermal shock severity and number of upshock cycles. Preliminary test results for monolithic silicon nitride (Si3N4) and silicon carbide (SiC), and one type of silicon based FRCMC, are presented. The test data are examined in terms of simple thermal shock theory.
    Keywords: COMPOSITE MATERIALS
    Type: NASA, Marshall Space Flight Center, Advanced Earth-to-Orbit Propulsion Technology 1988, Volume 1; p 730-741
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  • 65
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    Lightweight composite reflector panels (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The Hexel Corp. has produced additional composite panels, based on JPL designs, that: (1) have increased the panel size from 0.15 to 0.40 meters, (2) have improved the as-manufactured surface precision 3.0 to approx. 1.0 micron RMS, (3) have utilized different numbers of face sheet plys, (4) have improved face sheet fiber orientation, (5) have variations of aluminum honeycomb core cell size, (6) have combined graphite/epoxy (Gr/Ep) face sheets with E-glass honeycomb cores, and (7) have used standard aluminum core with face sheets composed of combinations of glass, Kevlar, and carbon fibers. Additionally, JPL has identified candidate alternate materials for the facesheets and core, modified the baseline polymer panel matrix material, and developed new concepts for panel composite cores. Dornier designed and fabricated three 0.6 meter Gr/Ep panels, that were evaluated by JPL. Results of both the Hexel and Dornier panel work were used to characterize the state-of-the-art for Gr/Ep mirrors.
    Keywords: COMPOSITE MATERIALS
    Type: Report of the Asilomar 3 LDR Workshop; p 74-75
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    Status of Gr/glass composites technology at UTOS (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The TSC (Thermally Stable Composite) refers to a family of graphite reinforced glass matrix composite materials developed by UTOS. This fiber matrix combination exhibits low coefficients of thermal expansion (CTE), exceptional dimensional stability, high specific strength and stiffness, adequate fracture toughness, and space environment compatibility. The dimensional stability of a TSC mirror structure was experimentally characterized at the Steward Observatory. Preliminary results indicate that TSC is significantly more thermally stable than most current structural composite materials. In addition, the use of lower CTE glass matrix materials, such as 96 percent silica glass, have the potential for producing graphite/glass panels with expansion rates and stability comparable to that of fused silica.
    Keywords: COMPOSITE MATERIALS
    Type: Jet Propulsion Lab., California Inst. of Tech., Report of the Asilomar 3 LDR Workshop; p 68-69
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    Advanced composite materials for precision segmented reflectors (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The objective in the NASA Precision Segmented Reflector (PSR) project is to develop new composite material concepts for highly stable and durable reflectors with precision surfaces. The project focuses on alternate material concepts such as the development of new low coefficient of thermal expansion resins as matrices for graphite fiber reinforced composites, quartz fiber reinforced epoxies, and graphite reinforced glass. Low residual stress fabrication methods will be developed. When coupon specimens of these new material concepts have demonstrated the required surface accuracies and resistance to thermal distortion and microcracking, reflector panels will be fabricated and tested in simulated space environments. An important part of the program is the analytical modeling of environmental stability of these new composite materials concepts through constitutive equation development, modeling of microdamage in the composite matrix, and prediction of long term stability (including viscoelasticity). These analyses include both closed form and finite element solutions at the micro and macro levels.
    Keywords: COMPOSITE MATERIALS
    Type: Jet Propulsion Lab., California Inst. of Tech., Report of the Asilomar 3 LDR Workshop; p 72-73
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    Propfan model wind tunnel aeroelastic research results (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Some of the single rotation propfan model wind tunnel aeroelastic findings from the experimental part of this research program are described. These findings include results for unstalled or classical flutter, blade response from separated flow excitations, and blade response from aerodynamic excitations at angled inflow conditions.
    Keywords: AERODYNAMICS
    Type: NASA, Lewis Research Center, Lewis Structures Technology, 1988. Volume 1: Structural Dynamics; p 273-286
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    Structural analyses of engine wall cooling concepts and materials (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The severe thermal environments under which hypersonic aircraft such as the National Aerospace Plane (NASP) will operate require cooling of the engine walls, especially in the combustor. A preliminary assessment is made of some candidate materials based on structural analyses for a number of convective cooling configurations. Three materials were studied: graphite/copper and tungsten/copper composite alloys with 50 percent fiber volume fractions and a wrought cobalt-base superalloy, Haynes 188. Anisotropic mechanical and thermal properties for the composites were obtained from a computer code, ICAN, which determines the composite material properties from the individual properties of the fiber and matrix materials. The structural analyses were performed by using the MARC nonlinear finite element code. Heat transfer analyses were conducted to calculate the metal temperature distributions.
    Keywords: COMPOSITE MATERIALS
    Type: NASA. Lewis Research Center, Lewis Structures Technology, 1988. Volume 2: Structural Mechanics; p 265-280
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  • 70
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    Impact damage in composite laminates (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Damage tolerance requirements have become an important consideration in the design and fabrication of composite structural components for modern aircraft. The ability of a component to contain a flaw of a given size without serious loss of its structural integrity is of prime concern. Composite laminates are particularly susceptible to damage caused by transverse impact loading. The ongoing program described is aimed at developing experimental and analytical methods that can be used to assess damage tolerance capabilities in composite structures subjected to impulsive loading. Some significant results of this work and the methodology used to obtain them are outlined.
    Keywords: COMPOSITE MATERIALS
    Type: Lewis Structures Technology, 1988. Volume 2: Structural Mechanics; p 235-243
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    Computational simulation methods for composite fracture mechanics (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Structural integrity, durability, and damage tolerance of advanced composites are assessed by studying damage initiation at various scales (micro, macro, and global) and accumulation and growth leading to global failure, quantitatively and qualitatively. In addition, various fracture toughness parameters associated with a typical damage and its growth must be determined. Computational structural analysis codes to aid the composite design engineer in performing these tasks were developed. CODSTRAN (COmposite Durability STRuctural ANalysis) is used to qualitatively and quantitatively assess the progressive damage occurring in composite structures due to mechanical and environmental loads. Next, methods are covered that are currently being developed and used at Lewis to predict interlaminar fracture toughness and related parameters of fiber composites given a prescribed damage. The general purpose finite element code MSC/NASTRAN was used to simulate the interlaminar fracture and the associated individual as well as mixed-mode strain energy release rates in fiber composites.
    Keywords: COMPOSITE MATERIALS
    Type: NASA. Lewis Research Center, Lewis Structures Technology, 1988. Volume 2: Structural Mechanics; p 157-169
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    Features and applications of the integrated composites analyzer (ICAN) code (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The thermal behavior of composite spacecraft antenna reflectors was investigated with the Integrated Composites Analyzer (ICAN) computer code. Parametric studies were conducted on the face sheets and honeycomb core which constitute the sandwich-type structures. Selected thermal and mechanical properties of the composite faces and sandwich structures are presented graphically as functions of varying fiber volume ratio, laminate configuration, fabrication factors, and environmental conditions.
    Keywords: COMPOSITE MATERIALS
    Type: Lewis Structures Technology, 1988. Volume 2: Structural Mechanics; p 99-112
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    A viscoplastic constitutive theory for metal matrix composites at high temperature (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A viscoplastic constitutive theory is presented for representing the high temperature deformation behavior of metal matrix composites. The point of view taken is a continuum one where the composite is considered a material in its own right, with its own properties that can be determined for the composite as a whole. It is assumed that a single preferential (fiber) direction is identifiable at each material point (continuum element) admitting the idealization of local transverse isotropy. A key ingredient is the specification of an experimental program for the complete determination of the material functions and parameters for characterizing a particular metal matrix composite. The parameters relating to the strength of anisotropy can be determined through tension/torsion tests on longitudinally and circumferentially reinforced thin walled tubes. Fundamental aspects of the theory are explored through a geometric interpretation of some basic features analogous to those of the classical theory of plasticity.
    Keywords: COMPOSITE MATERIALS
    Type: NASA. Lewis Research Center, Nonlinear Constitutive Relations for High Temperature Applications, 1986; p 7-25
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    Comparison of experimental rotor damping data-reduction techniques (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The ability of existing data reduction techniques to determine frequency and damping from transient time-history records was evaluated. Analog data records representative of small-scale helicopter aeroelastic stability tests were analyzed. The data records were selected to provide information on the accuracy of reduced frequency and decay coefficients as a function of modal damping level, modal frequency, number of modes present in the time history record, proximity to other modes with different frequencies, steady offset in time history, and signal-to-noise ratio. The study utilized the results from each of the major U.S. helicopter manufacturers, the U.S. Army Aeroflightdynamics Directorate, and NASA Ames Research Center using their inhouse data reduction and analysis techniques. Consequently, the accuracy of different data analysis techniques and the manner in which they were implemented were also evaluated. It was found that modal frequencies can be accurately determined even in the presence of significant random and periodic noise. Identified decay coefficients do, however, show considerable variation, particularly for highly damped modes. The manner in which the data are reduced and the role of the data analyst was shown to be important. Although several different damping determination methods were used, no clear trends were evident for the observed differences between the individual analysis techniques. It is concluded that the data reduction of modal-damping characteristics from transient time histories results in a range of damping values.
    Keywords: AERODYNAMICS
    Type: Integrated Technology Rotor Methodology Assessment Workshop; p 231-248
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    Aeroelastic modeling of rotor blades with spanwise variable elastic axis offset: Classic issues revisited and new formulations (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: In response to a systematic methodology assessment program directed to the aeroelastic stability of hingeless helicopter rotor blades, improved basic aeroelastic reformulations and new formulations relating to structural sweep were achieved. Correlational results are presented showing the substantially improved performance of the G400 aeroelastic analysis incorporating these new formulations. The formulations pertain partly to sundry solutions to classic problem areas, relating to dynamic inflow with vortex-ring state operation and basic blade kinematics, but mostly to improved physical modeling of elastic axis offset (structural sweep) in the presence of nonlinear structural twist. Specific issues addressed are an alternate modeling of the delta EI torsional excitation due to compound bending using a force integration approach, and the detailed kinematic representation of an elastically deflected point mass of a beam with both structural sweep and nonlinear twist.
    Keywords: AERODYNAMICS
    Type: NASA, Ames Research Center, Integrated Technology Rotor Methodology Assessment Workshop; p 217-22
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    Delamination durability of composite materials for rotorcraft (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Delamination is the most commonly observed failure mode in composite rotorcraft dynamic components. Although delamination may not cause immediate failure of the composite part, it often precipitates component repair or replacement, which inhibits fleet readiness, and results in increased life cycle costs. A fracture mechanics approach for analyzing, characterizing, and designing against delamination will be outlined. Examples of delamination problems will be illustrated where the strain energy release rate associated with delamination growth was found to be a useful generic parameter, independent of thickness, layup, and delamination source, for characterizing delamination failure. Several analysis techniques for calculating strain energy release rates for delamination from a variety of sources will be outlined. Current efforts to develop ASTM standard test methods for measuring interlaminar fracture toughness and developing delamination failure criteria will be reviewed. A technique for quantifying delamination durability due to cyclic loading will be presented. The use of this technique for predicting fatigue life of composite laminates and developing a fatigue design philosophy for composite structural components will be reviewed.
    Keywords: COMPOSITE MATERIALS
    Type: NASA, Washington, NASA(Army Rotorcraft Technology. Volume 2: Materials and Structures, Propulsion and Drive Systems, Flight Dynamics and Control, and Acoustics; p 573-605
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    Comprehensive rotorcraft analysis methods (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The development and application of comprehensive rotorcraft analysis methods in the field of rotorcraft technology are described. These large scale analyses and the resulting computer programs are intended to treat the complex aeromechanical phenomena that describe the behavior of rotorcraft. They may be used to predict rotor aerodynamics, acoustic, performance, stability and control, handling qualities, loads and vibrations, structures, dynamics, and aeroelastic stability characteristics for a variety of applications including research, preliminary and detail design, and evaluation and treatment of field problems. The principal comprehensive methods developed or under development in recent years and generally available to the rotorcraft community because of US Army Aviation Research and Technology Activity (ARTA) sponsorship of all or part of the software systems are the Rotorcraft Flight Simulation (C81), Dynamic System Coupler (DYSCO), Coupled Rotor/Airframe Vibration Analysis Program (SIMVIB), Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD), General Rotorcraft Aeromechanical Stability Program (GRASP), and Second Generation Comprehensive Helicopter Analysis System (2GCHAS).
    Keywords: AERODYNAMICS
    Type: NASA, Washington, NASA(Army Rotorcraft Technology. Volume 1: Aerodynamics, and Dynamics and Aeroelasticity; p 312-352
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    Missile aerodynamics (1988)
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    Publication Date: 2011-08-19
    Description: The fundamental aerodynamics of slender bodies is examined in the reprint edition of an introductory textbook originally published in 1960. Chapters are devoted to the formulas commonly used in missile aerodynamics; slender-body theory at supersonic and subsonic speeds; vortices in viscid and inviscid flow; wing-body interference; downwash, sidewash, and the wake; wing-tail interference; aerodynamic controls; pressure foredrag, base drag, and skin friction; and stability derivatives. Diagrams, graphs, tables of terms and formulas are provided.
    Keywords: AERODYNAMICS
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    Viscous transonic airfoil workshop compendium of results (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 1073-108
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  • 80
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    Transonic unsteady aerodynamic and aeroelastic calculations about airfoils and wings (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Recent advances in the numerical simulation of unsteady transonic flow around airfoils and wings are surveyed, with an emphasis on the treatment of aeroelastic effects. The fundamental physical principles involved are discussed, and the numerical implementation of the methods is considered. Typical results are presented in extensive graphs and diagrams and briefly characterized, with reference to experimental data.
    Keywords: AERODYNAMICS
    Type: Computers and Structures (ISSN 0045-7949); 30; 4, 19
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    Analytical and experimental investigation of the notched strength of thick laminates with surface notches (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Experimental and analytical investigations of the fracture of a graphite/epoxy laminate with part-through semielliptic surface notches have been conducted. Experimental values of notched strength were determined for a variety of notch aspect ratios and notch depths. Analytical predictions of laminate failure were obtained from three different models. The three models were equally successful in predicting the fracture of laminates with deep notches. The experimental results of laminates with shallow notches indicated more notch sensitivity (that is greater strength reduction) than did the analytical models.
    Keywords: COMPOSITE MATERIALS
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    The correlation of low-velocity impact resistance of graphite-fiber-reinforced composites with matrix properties (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Summarized are basic studies that were conducted to correlate the impact resistance of graphite-fiber-reinforced composites with polymer matrix properties. Three crosslinked epoxy resins and a linear polysulfone were selected as composite matrices. As a group, these resins possess a significantly large range of mechanical properties. The mechanical properties of the resins and their respective composites were measured. Neat resin specimens and unidirectional and crossply composite specimens were impact tested with an instrumented dropweight tester. Impact resistances of the specimens were assesseed on the basis of loading capability, energy absorption, and extent of damage.
    Keywords: COMPOSITE MATERIALS
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    Analytical modeling of helicopter static and dynamic induced velocity in GRASP (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The methodology used by the General Rotorcraft Aeromechanical Stability Program (GRASP) to model the characteristics of the flow through a helicopter rotor in hovering or axial flight is described. Since the induced flow plays a significant role in determining the aeroelastic properties of rotorcraft, the computation of the induced flow is an important aspect of the program. Because of the combined finite-element/multibody methodology used as the basis for GRASP, the implementation of induced velocity calculations presented an unusual challenge to the developers. To preserve the modelling flexibility and generality of the code, it was necessary to depart from the traditional methods of computing the induced velocity. This is accomplished by calculating the actuator disk contributions to the rotor loads in a separate element called the air mass element, and then performing the calculations of the aerodynamic forces on individual blade elements within the aeroelastic beam element.
    Keywords: AERODYNAMICS
    Type: Vertica (ISSN 0360-5450); 12; 4, 19; 337-344
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  • 84
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    An experimental and computational study of rotor-vortex interactions (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: An experimental and computational study has been performed on a close rotor-blade/vortex interaction. Surface pressure data was obtained from a rotor operating close to the tip-vortex from an upstream wing in a wind tunnel. Data was obtained for a wide range of blade-vortex proximities, orientations, and blade-tip Mach numbers (up to the transonic regime). A numerical model of these interactions was constructed using the unsteady, three-dimensional, full-potential rotor code called FPR. The model employed an undistorted full-field representation of the measured vortex. This simple model gave excellent comparisons with the data for a wide range of conditions, including parallel head-on interactions. Computational studies have also been performed on the manner of vortex representation and the influence of vortex-core size.
    Keywords: AERODYNAMICS
    Type: Vertica (ISSN 0360-5450); 12; 4, 19
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    Thermal expansion measurements of metal matrix composites (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The laser-interferometric-dilatometer system currently operational at NASA-Langley is described. The system, designed to characterize metal matrix composites, features high precision, automated data acquisition, and the ability to test a wide variety of specimen geometries over temperature ranges within 80-422 K. The paper presents typical thermal-expansion measurement data for a Gr/Al rod; Gr/Al and Gr/Mg unidirectional laminates; and a Gr/Mg (+ or -8)s laminate.
    Keywords: COMPOSITE MATERIALS
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    Thermal-mechanical fatigue test apparatus for metal matrix composites and joint attachments (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Two thermal-mechanical fatigue (TMF) test facilities were designed and developed, one to test tungsten fiber reinforced metal matrix composite specimens at temperature up to 1430C (2600F) and another to test composite/metal attachment bond joints at temperatures up to 760F (1400F). The TMF facility designed for testing tungsten fiber reinforced metal matrix composites permits test specimen temperature excursions from room temperature to 1430C (2600F) with controlled heating and loading rates. A strain-measuring device measures the strain in the test section of the specimen during each heating and cooling cycle with superimposed loads. Data is collected and recorded by a computer. The second facility is designed to test composite/metal attachment bond joints and to permit heating to a maximum temperature of 760C (1400F) within 10 min and cooling to 150C (300F) within 3 min. A computer controls specimen temperature and load cycling.
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    Euler solution of multiblade rotor flow (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A numerical method for solving the Euler equations for multiblade rotors has been developed and some preliminary results reported. The numerical scheme is a combination of several recent methods and algorithm improvements, adapted to the particular requirements of rotor-body interactions. A cylindrical basic grid has been used to study conventional multiblade helicopter rotors. Test calculations have been made for two- and six-blade rotors in hover and for a two-blade rotor in forward flight, under transonic tip conditions but without lift. The results show good agreement with experimental data.
    Keywords: AERODYNAMICS
    Type: Vertica (ISSN 0360-5450); 12; 3, 19; 303-313
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    Spur-type instability observed on numerically simulated vortex filaments (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: An instability observed on vortex filaments during numerical simulations of the three-dimensional, time-dependent dynamics of vortex wakes is studied to determine when and why it occurs. It is concluded that the observed instability is a consequence of the use of straight-line vortex segments of finite length to model continuously curving vortex filaments. The instability appears to occur only when the link length is a sizable fraction of the vortex span and, therefore, is not expected in an experiment. Guidelines are then given that help avoid numerical instabilities when vortex filaments are used in flow simulations.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 25; 835-841
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    Monte Carlo simulations in support of the Shuttle upper atmospheric mass spectrometer experiment (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Thermophysics and Heat Transfer (ISSN 0887-8722); 2; 138-144
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    Numerical prediction of flow in slender vortices (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The slender vortex approximation was investigated using the Navier-Stokes equations written in cylindrical coordinates. It is shown that, for free vortices without external pressure gradient, the breakdown length is proportional to the Reynolds number. For free vortices with adverse pressure gradients, the breakdown length is inversely proportional to the value of its gradient. For low Reynolds numbers, the predictions of the simplified system agreed well with the ones obtained from solutions of the full Navier-Stokes equations, whereas for high Reynolds numbers, the flow became quite sensitive to pressure fluctuations; it was found that the failure of the slender vortex equations corresponded to the critical condition as identified by Benjamin (1962) for inviscid flows. The predictions obtained from the approximating system were compared with available experimental results. For low swirl, a good agreement was obtained; for high swirl, on the other hand, upstream effects on the pressure gradient produced by the breakdown bubble caused poor agreement.
    Keywords: AERODYNAMICS
    Type: Computers and Fluids (ISSN 0045-7930); 16; 3, 19
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    Thermal properties of composites with bismaleimide-vinyl poly(styrylpyridine) blends (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Thermal properties, flammability, and selected mechanical properties of eight different graphite composite panels fabricated using four different resin matrices and two types of graphite reinforcement were investigated and compared with the properties of an epoxy composite, MXB 7203. The resin matrices included XU71775/H795, a blend of vinyl poly(styrylpyridine) and bismaleimide; H795, a bismaleimide; Cycom 6162, a phenolic; and PSP 6022M, a poly(styrylpyridine). The graphite fiber was AS-4 used in the form of tape or fabric. It was found that the XU71775/H795 blend with the graphite tape was the optimum design giving the lowest heat release rate, while the control epoxy panel exhibited the highest total heat release and heat release rates, highest smoke and CO evolution, highest mass losses, and lowest oxygen index of all the composites tested.
    Keywords: COMPOSITE MATERIALS
    Type: Polymer Composites (ISSN 0272-8397); 9; 172-183
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    Bismaleimide-vinylpolystyrylpyridine graphite composites (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Flammability, thermal, and selected mechanical properties of composites fabricated with epoxy and other thermally stable resin matrices are described. Properties which were measured included limiting-oxygen index, smoke evolution, thermal degradation products, total-heat release, heat-release rates, mass loss, flame spread, ignition resistance, thermogravimetric analysis and selected mechanical properties. This paper describes the properties of eight different graphite composite panels fabricated using four different resin matrices and two types of graphite reinforcement. The resin matrices included: XU71775/H795, a blend of vinylpolystyrylpyridine and bismaleimide; H795, a bismaleimide; Cycom 6162, a phenolic; and PSP 6022M, a polystyrylpyridine. The graphite fiber used was AS-4 in the form of either tape or fabric. The properties of these composites were compared with epoxy composites. It was determined that the blend of vinylpolystyrylpyridine and bismaleimide (XU71775/H795) with the graphite tape was the optimum design giving the lowest heat release rate.
    Keywords: COMPOSITE MATERIALS
    Type: Journal of Thermoplastic Composite Materials (ISSN 0892-7057); 1; 12-38
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    NLF technology is ready to go (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Natural laminar flow (NLF) can reduce drag on aircraft developed using modern structural design methods. Modern metal and composite construction methods can meet NLF requirements for subsonic commuter and business airframes. NLF research at NASA concentrates on expanding the practical application of NLF drag reduction technology; payoffs include progress with liquid-crystal flow visualization, NLF on three-dimensional bodies, and the effects of acoustics on laminar stability. Fuel savings from 2 to 4 percent are expected if laminar flow could be achieved over the forward 50 percent of engine nacelles on large transports depending on the configuration. It is concluded that the skill required to use NLF for drag reduction depends on understanding the conservative design corridors within which laminar flow is durable and reliable.
    Keywords: AERODYNAMICS
    Type: Aerospace America (ISSN 0740-722X); 26; 16
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    The fix for tough spots (1988)
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    Publication Date: 2011-08-19
    Description: Modern turbulence-control techniques are discussed. Particular atention is given to retrofit techniques such as riblets and large-eddy breakup (LEBU) devices which use passive elements suitable for a variety of existing vehicles with minimum added complexity. Riblets are small flow-aligned grooves in the aircraft skin that damp turbulence and reduce skin friction; the mechanism of riblet drag reduction derives from the enhancement of turbulence-altering, transverse viscous forces by strong spanwise surface geometry gradients. LEBUs are thin plates or ribbons suspended in a turbulent boundary layer to sever or break up the large vortices that form the convoluted outer edge of the layer. Other turbulence-control techniques are discussed, including one that involves the injection of control vortices into the turbulent boundary layer to modify or substitute for large-eddy structures.
    Keywords: AERODYNAMICS
    Type: Aerospace America (ISSN 0740-722X); 26; 24
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    Laminar flow control is maturing (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Recent research demonstrates that laminar flow (LF) can be reliable in flight and that the support system need not be complex. Shaping produces favorable pressure gradients for maintaining natural laminar flow (NLF), and laminar flow control (LFC) techniques such as full chord suction promise a fuel-saving payoff of up to 30 percent on long-range missions. For large aircraft, current research is concentrated on hybrid LFC concepts which combine suction and pressure-gradient control. At NASA Ames, an F-14 with variable wing sweep has been flight tested with smooth surface gloves on the wings; preliminary results indicate high transition Reynolds numbers to sweep angles as large as 25 deg. In addition, a 757 was flight tested with an NLF glove on the right wing just outboard of the engine pylon; and the LF was found to be suprisingly robust.
    Keywords: AERODYNAMICS
    Type: Aerospace America (ISSN 0740-722X); 26; 20
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  • 96
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    Composite materials: Testing and design (1988)
    In:  Other Sources
    Details
    Publication Date: 2016-03-09
    Description: The present conference discusses topics in the analysis of composite structures, composite materials' impact and compression behavior, composite materials characterization methods, composite failure mechanisms, NDE methods for composites, and filament-wound and woven composite materials' fabrication. Attention is given to the automated design of a composite plate for damage tolerance, the effects of adhesive layers on composite laminate impact damage, instability-related delamination growth in thermoset and thermoplastic composites, a simple shear fatigue test for unidirectional E-glass epoxy, the growth of elliptic delaminations in laminates under cyclic transverse shear, and the mechanical behavior of braided composite materials.
    Keywords: COMPOSITE MATERIALS
    Format: text
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    NASA TECHNICAL REPORTS
  • 97
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    Numerical study of the skin friction on a spheroid at incidence (1988)
    In:  Other Sources
    Details
    Publication Date: 2016-03-09
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 26; 129-136
    Format: text
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    NASA TECHNICAL REPORTS
  • 98
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    Instability-related delamination growth of embedded and edge delaminations (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Compressive loads can cause local buckling in composite laminates that have a near surface delamination. This buckling causes load redistribution and secondary loads, which in turn cause interlaminar stresses and delamination growth. The goal of this research was to enhance the understanding of this instability-related delamination growth in laminates containing either an embedded or an edge delamination.
    Keywords: COMPOSITE MATERIALS
    Type: NASA-TM-100655 , NAS 1.15:100655
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 99
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    Computation of the tip vortex flowfield for advanced aircraft propellers (1988)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The tip vortex flowfield plays a significant role in the performance of advanced aircraft propellers. The flowfield in the tip region is complex, three-dimensional and viscous with large secondary velocities. An analysis is presented using an approximate set of equations which contains the physics required by the tip vortex flowfield, but which does not require the resources of the full Navier-Stokes equations. A computer code was developed to predict the tip vortex flowfield of advanced aircraft propellers. A grid generation package was developed to allow specification of a variety of advanced aircraft propeller shapes. Calculations of the tip vortex generation on an SR3 type blade at high Reynolds numbers were made using this code and a parametric study was performed to show the effect of tip thickness on tip vortex intensity. In addition, calculations of the tip vortex generation on a NACA 0012 type blade were made, including the flowfield downstream of the blade trailing edge. Comparison of flowfield calculations with experimental data from an F4 blade was made. A user's manual was also prepared for the computer code (NASA CR-182178).
    Keywords: AERODYNAMICS
    Type: NASA-CR-182179 , NAS 1.26:182179 , R88-900064-F
    Format: application/pdf
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  • 100
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    Overview of CFD methods and comparison with flight aerothermal data (1988)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: An overview of previously published aerothermal investigations which demonstrate the capabilities of detailed computational fluid dynamics and engineering codes to predict the aerothermal environment about an entry vehicle is presented. The overview consists of a brief discussion of the computational methods and experimental data and includes comparisons between the computed results and data. The overview focuses primarily on analyses of flight data since these data provide the unique capability to assess the real-gas chemistry options in the codes. The computed results are based on a series of codes which are employed by the Aerothermodynamics Branch of the Space System Division at the Langley Research Center. The flight data, which were measured on the Reentry F, the Space Shuttle, and the Fire II vehicles, represent a wide range of vehicle configurations and freestream conditions. Also, results of one recent set of ground tests are included since the tests provide data on a model of a pending flight project. The comparisons of the predicted results and data demonstrate the adequacy of the present computational fluid dynamics capabilities and indicate the potential to predict the aerothermal environment about future flight vehicles.
    Keywords: AERODYNAMICS
    Type: AGARD, Validation of Computational Fluid Dynamics. Volume 2: Poster Papers; 17 p
    Format: text
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