Measurements of temperature and pressure have been made on two models with stagnation-point, single-hole, mass injection ratios from zero to 99 and at 0, 5, 10, and 20 degrees angle-of-attack in the nasa langley 8' high temperature-structures-tunnel. these raw-data have not been reduced to… More

The effective utilization of the aedc track g facility to evaluate the erosion performance of reentry vehicle nosetip materials in weather environments has been limited by a lack of insight into physical phenomena peculiar to track testing. the purpose of the proposed investigation is to analyze and… More

Carbon ablation data obtained in high pressure ablation tests (aedc track g) will be correlated with theory, including possible effects of melting, the uncertainties in the ablation theory that are consistent with the ground testdata will be defined. the results will then be used to predict the… More

Antenna windows critically affect the performance of advanced reentry systems. in many cases compromises in vehicle effectiveness must be made because of window material limitations. to aid in the improvement of window, and therefore overall performance, an analysis study is proposed to (1) evaluate… More

Four major classes of directed energy weapons are being evaluated for defense against icbms: cw laser, pulse laser, particle beams, and x-ray lasers. the vulnerability and first-order hardening methods for an existing u.s. icbm (peacekeeper) will be identified and evaluated in the proposed effort.… More

Some proposed cw laser weaponshavebeam diameters on the order of a meter with flux levels exceeding 2kw/cm. there is evidence that laser beam attenuation by ablation products will be significant for this type of weapon in some target flight regimes. the objectives of the project will be to: (1)… More

The exit shrouds on fast-launch icbms will experience thermal, structural, and erosive environments that are significantly more severe than on conventional icbm's. this program will evaluate these environments and determine the effects of system design parameters, such as trajectory, geometry, and… More

Studies will be conducted to define ground tests to measure the effects of flowfield plasma on radar beam attenuation and deflection. reentry flight environments will be analyzed to define simulation requirements, test facilities and experimental approaches will be selected, and a test plan will be… More

A requirement exists to inspect and calibrate transpiration cooled nosetips (tcnt) and other hardware which utilize transpiration cooling. the proposed program addresses the feasibility demonstration of critical elements and a preliminary design of a high resolution fully automated… More

U.s. response to current soviet icbm defense has included the development of penetration aid systems to deny or delay the acquisition of u.s. reentry vehicles. with deployment of soviet directed energy weapons (dew), the effectiveness of these countermeasures may be reduced. in the proposed program,… More

Studies will be conducted to define feasible aft cover design that exploit the improved properties of new advanced materials to enhance survivability in anticipated future nuclear environments. geometric design configurations and candidate materials that satisfy the design constraints will be… More

A requirement exists for the precision inspection of the aedc track g facility between shots to survey for damage to as well as misalignment. the critical facility elements which provide bearing surfaces for the hypervelocity model. the proposed program addresses this need. a baseline self-contained… More

The thermostructural performance sensitivity of nozzles to changes in carbon-carbon composite material properties has been a significant problem. the proposed study will identify critical properties and develop a test matrix for for characterizing changes in these properties as a function of… More

The feasibility and performance limits of transpiration cooled nosetips, (tcnt's) using a warm gas coolant will be investigated. such concepts have the potential of combining the reliable maintenance free coolant supply of existing gas-jet nosetip concepts with the relatively predictable performance… More

Several government advanced technology programs (tav, bvg, elite, etc.) have proposed systems which require "hot" structures, capable of sustaining operational loads at exposure temperatures of 2500 deg f and higher. the most promising material candidate for these hot structure applications is… More

Plasma treatment of polyaramid filaments with amines to induce surface chemistry modification has created improved performance kevlar/epoxy composites. performance improvement has been attributed to the development of covalent bonds, but limited data suggests that the surface energetics… More

Several government advanced technology programs (elite, tav, bgv), etc.) are proposing systems which require structural components capable of sustaining operational loads at exposure temperatures of 3000 deg f and higher. the most promising material solution for these hot structure applications is… More

The deficiencies in current antenna window materials and design methods restrict the performance goals of certain advanced air force systems. to improve the performance of antenna windows and therefore improve overall system effectiveness, material formulations, material constructions and design… More

For certain air force advanced reentry applications, antenna window performance has a critical role in dictating overall system effectiveness. to aid in the characterization of antenna window performance, reentry data are needed in the areas of ablation, thermal, structural and electrical response.… More

Advanced maneuvering reentry systems require installation of a large phased array antenna in the vehicle shell structure. the large physical size of the required cutout combined with the severe maneuvering and nuclear airblast loads place severe demands on the structural attachment between the… More

The department of defense is allocating significant resources to explore development of novel short wavelength laser (swl) concepts into weapon grade systems. the design goals for these weapons have been established largely on the basis of lethality data obtained with ir lasers. in the proposed… More

The copper/epoxy composite material is anticipated to be a limited factor in achieving the desired performance of superconducting magnets in fusion energy systems. this results from the low radiation hardness of epoxy resins, the degradation in mechanical properties as a result of neutron and gamma… More

Plasma treatment of polyaramid filaments with amines to induce surface chemical modification, has created improved performance kevlar/ epoxy composites. covalent bonds are established between the two constituents when plasma treatment ablates the polyaramid oxidized hydrocarbon surface layer and… More

The response of a hard mobile launcher (hml) in a nuclear airblast environment is strongly dependent on the drag loads produced by the two phase fluid-particle gust behind the blast wave. the objective of this proposed research is to demonstrate the feasibility of conducting credible aero/dust load… More

A method of demonstrating computer tomography (ct) as a quantitative nondestructive evaluation tool for low temperature composites in proposed. the feasibility of ct applied to flat laminate plate and filament wound cylindrical specimens fabricated from glass fiber/epoxy and graphite fiber/epoxy… More

A method of demonstrating computed tomography (ct) teamed with software image processing methods as a quantitative means of evaluating bone structure, density and geometry of the human musculoskeletal system is proposed. the feasibility of ct techniques applied to osteoporosis femur specimens in… More

Carbon/phenolic composites suffer from low interfacial bond strengths, the result of poor secondary bonding and the failure to develop covalent bonds at the fiber-matrix interface. the consequences are a composite material system with major limitations due to low interfacial shear and transverse… More

Optical devices may be exposed to direct or indirect thermal radiation from fireballs on the tactical nuclear battlefield. the fireball thermal radiation persists for several seconds, depending on the yield and detonation altitude of the nuclear weapon. the total blackbody fluence radiated to the… More

We propose a combined program of analysis and accelerated aging to determine the origin of instabilities in fluid solutions of the radiochromic dyes used in optical waveguide dosimeters. chromatographic and spectrophotometric techniques will be used to separate and identify impurities in dyes and… More

Manufacturing problems involved with the fusion and compaction of advanced thermoplastic-graphite precursor tape in construction of composite structures having contoured shapes has seriously retarded the acceptance of these high performance materials by industry. the 700 to 800 deg f fusion… More

The feasibility of a centralized finite element modeling and analysis data base system for the support of united states air force (usaf) aircraft structures will be assessed. the centralized system must be able to obtain, develop, modify, evaluate, certify, and apply these finite element models in… More

Titanium has a unique combination of thermophysical properties which result in oxidation susceptibility. a number of coatings have been developed for titanium to improve its oxidation resistance. coating processes for titanium present a variety of problems and all possess limitations. chemical vapor… More

Organic fibers, such as polyethylene, are extremely attractive for rotating machinery, energy storage devices because of high specific longitudinal strength and stiffness properties. the major limitation in these types of applications (e.g., flywheels) is the low transverse tensile strength of the… More

Thermoplastic polymers, with characteristics of high strain-to-failure, rapid formability and reprocessing capability, are attractive as matrix materials for composite material systems. a major limitation is that thermoplastic composites exhibit low fiber/matrix adhesion. contributing factors… More

A new low cost casting method has been developed to produce silicon/ carbide aluminum (sic/al) with inexpensive raw materials and conventional foundry techniques. limited material tests and cost projections indicate that sic/al posses many characteristics that make it a desirable materials… More

Isce accumulation on the trailing wire antenna will change its aerodynamic tow characteristics. in general, it causes increased drag, changes the deployed wire shape and can affect the dynamic stability of the cable. if ice build-up is not controlled, it can lead to tension failure of the wire… More

Plasma amination was successfully applied to low and inter- mediate modulus graphite fibers. amine concentration densi-ties exceeded 1.6 and 0.6 nh2/100a2, respectively. ammonia plasma exposure induced no damage in low modulus fibers; intermediate modulus were not tested. peel strength of an… More

A method for fusion and compaction in-situ filament winding with advanced thermoplastic/graphite fiber co-mingled strands is proposed. heat for fusion will be supplied through electromagnetic induction currents. exploratory experiments have shown that eddy current heatingof graphite fibers can be… More

A lightweight gondola is proposed which uses the advantages of advanced composites and the improved interlaminar properties of amine plasma-treated kevlar/epoxy to provide a versatile, modular structure which is easily adaptable to various payload requirements. two design concepts with separable… More

Significant increases in stiffness, wear and fatigue resistance were observed in cast sic/al-a201-t6 relative to the base alloy. high temperature strength improvements werenot obtained with the addition of sic, however, other sources indicate strength improvements are obtainable through the use of… More

Carbon and graphite fibers have relatively poor oxidation resistance. their utility in high temperature applications can be enhanced by a well adhering oxidation resistant coating. such coatings also have the potential for improving interfacial adhesion with matrix resins. the goal of this program… More

Remote fiber spectroscopy coupled with fiber optic chemical sensors has shown promise for groundwater monitoring. laser-induced fluorescence has been principal diagnostic technique investigated for the measurement of organochlorides and other common groundwater containments. laboratory and model… More

Pda proposes to conduct a feasibility study on the employment of three technologies to improve the preprocessing techniques applied to input data for vulnerability assessment computer codes. this study will evaluate computer graphics systems, database management systems, and expert or knowledge… More

A need exists to develop a reliable and accurate device to meter particles into the high pressure section of arc heaters to support the high temperature erosion test capabilities at aedc. such devices are needed for both the heat - h1 and dust erosion tunnel (det) facilities. the preliminary… More

The objective of this program is to develop laboratory apparatus to measure the spectral emittance of material samples at high temperatures. the apparatus will be capable of making the measurements over a range of from 0 to 10 microns. the design goal is to permit measurements at sample temperatures… More

New reentry vehicle concepts under development by the air force have antenna window requirements that push the limits of current design technology. the objective of this program is to investigate materials and design options developed to meet advanced reentry system requirements without compromising… More

The objective of this program is to develop and evaluate a general purpose areodynamic shear gauge concept for use in the arnold engineering development center von karman gas dynamic wind tunnels. the gauge will be sufficiently sensitive for both laminar and turbulent flow shear measurements and… More

Torpedo hull sections are currently either cast or forged from aluminum. due to the inherently moderate strength and stiffness to weight ratios afforded by aluminum, relatively thick torpedo hull sections are required to withstand the hydrodynamic loads encountered during deep depth operations as… More

Accurate predictions of the window/heatshield ablated shape and in-depth heat transfer are vital to ensure vehicle survival and the antenna window's transmission performance. these predictions require accurate thermophysical property data on the material. some of the thermophysical data currently… More

The detection and characterization of defects in solid propellants, nozzles, cones and other propulsion components are of great importance in the manufacturing of solid rocket motors. to implement the required quality control, proper test methods that can be carried out at the manufacturing site… More

Aircraft repair in a field environment demands a fast acting effective process that is extremely versatile. induction heating is well suited for field level repair in that it is a very fast heating technique and it can be made to operate on available power sources. the problem with current induction… More

Current nde methods are largely dependent upon qualitative indicators. tomographic nde methods offer the potential of developing quantitative accept/reject criteria. computed x-ray tomography (ct) can define material characteristics, such as density, on a spatially-resolved basis. the development of… More

Thermoplastics, being semicrystalline materials are sensitive to process history. crystallinity significantly affects mechanical properties. relationships governing nucleation and crystal growth in fiber-reinforced thermoplastics are poorly understood. crystals can be preferentially nucleated at and… More

The westar/palapa satelite launch events, in which two-dimensional (2d) carbon-carbon (c-c) rocket nozzle exit cones failed and caused a loss of mission, points graphically to the inadequacies of the design -analysis- manufacturing -test- and inspection process. we believe that the lack of… More

Carbon-phenolic materials have been widely used in solid rocket motors (srms) for many years, despite the fact that their thermostructural behavior has not been well understood. the application of carbon-phenolic to the man-rated space shuttle srms, however, has necessitated the capability for… More

Films of radiochromic dosimetry material coupled with filters provide both dose and spectral information on nuclear tests, a substantial monitoring capability. the diagnostic devices, however, occupy substantial volume; the materials bleach due to radiation damage and are prone to dye migration. all… More

A series of well characterized im6/3501-6 composite plates will be exposed to controlled, will instrumented jp4 pool fires of varying duration. fire exposed plates will be characterized using pulse-echo ultrasonic, microscopy, dsc, tag and mechanical testing in flexure and short beam shear.… More

A family of reactive coupling agents based upon an exothermic decomposition is being developed. the reaction may be initiated thermally or with actinic light. initiation may be varied over a wide range of temperatures or wavelengths, which allows the bonding reaction to be tailored to the adhesive… More

Development of reactive primer/modified phenolic adhesive system is proposed for bonding radome materials. initial studies have shown that the reactive primer chemistry will form chemical bonds with metals, ceramics and polymers. a two-stage primer is proposed that can be bonded to a radome… More

Integral fuel tanks are common to aircraft systems. fuel tank repairs are significiant cost item because of maintenance frequency and time to affect repair. conventional fuel tank sealants, such as polysulfides, require hours to cure. this is a major contributor to repair time. a reactive adhesive… More

A phase i program is proposed to establish the feasibility of using photochromic dyes previously developed for thermal protection systems to achieve passive solar control chamcteristics in aircraft cockpit transparencies. the photochromic response to sunlight would cause the transmittance of the… More

Carbon-phenolic (c/ph) composites have been widely used in solid rocket motors despite the fact that their high-temperature, thermostructural behavior is not well understood. many of the failure modes (e.g., wedge-out, ply-lift, delamination, pocketing) commonly seen in the c/phcomponents of fired… More

The sensitivity of the thermostructural performance of rocket nozzles to changes in carbon-carbon composite material properties has been a significant problem. resultsof an air force study have clearly indicated that significant gains in structural reliability could be achieved by adopting a rotated… More

One mission of the Naval Special Warfare forces is both location and neutralization of very shallow water anit-invasion mines. This proposal addresses the mine neutralization aspect of the problem. PDA has been developing high speed underwater rockets and projectiles for the past six years for the… More