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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3

High temperature acoustic and hybrid microwave/acoustic levitators for materials processing

The physical acoustics group at the Jet Propulsion Laboratory developed a single mode acoustic levitator technique for advanced containerless materials processing. The technique was successfully demonstrated in ground based studies to temperatures of about 1000 C in a uniform temperature furnace environment and to temperatures of about 1500 C using laser beams to locally heat the sample. Researchers are evaluating microwaves as a more efficient means than lasers for locally heating a positioned sample. Recent tests of a prototype single mode hybrid microwave/acoustic levitator successfully demonstrated the feasibility of using microwave power as a heating source. The potential advantages of combining acoustic positioning forces and microwave heating for containerless processing investigations are presented in outline form.

Barmatz, Martin↗

Waste treatment integration in space

The circumstances and criteria for space-based waste treatment bioregenerative life-support systems differ in many ways from those needed in terrestrial applications. In fact, the term "waste" may not even be appropriate in the context of nearly closed, cycling, ecosystems such as those under consideration. Because of these constraints there is a need for innovative approaches to the problem of "materials recycling". Hybrid physico-chemico-biological systems offer advantages over both strictly physico-chemico or biological approaches that would be beneficial to material recycling. To effectively emulate terrestrial cycling, the use of various microbial consortia ("assemblies of interdependent microbes") should be seriously considered for the biological components of such systems. This paper will examine the use of consortia in the context of a hybrid-system for materials recycling in space.

Waste Management/methods↗

Flexural Fatigue Testing and Qualification of Hybrid PAN-pitch Composite Materials with High Through-Thickness Thermal Conductivity

Carbon-fiber-reinforced polymers (CFRPs) considered for motor components within future electric vertical takeoff and landing (eVTOL) vehicles require not only a high strength-to-weight ratio but also a high through-thickness thermal conductivity (TC) to dissipate heat. Previously, CFRPs incorporating pitch CF interleaves demonstrated an increased through-thickness TC relative to the baseline composite, but the effect on flexural fatigue life was not evaluated. For this work, T700S/TC275–1 braided carbon fiber/epoxy prepreg baseline (no interleave), YSH–60A pitch interleave, and YS–80A pitch interleave configurations were tested for fatigue life. A combination of ASTM International Standards D7264 and D3479 were used to develop a reliable testing method. An Instron® (Illinois Tool Works Inc.) 8501 servohydraulic system with a fatigue test fixture was set up with a 16:1 span:thickness ratio, load ratio R set to 0.1, and frequency of 4 Hz. High-cycle fatigue testing was completed, and it was found that YSH–60A interleave performed slightly better than YS–80A below 100,000 cycles but showed no differences above 100,000 cycles. In all cases, the baseline CFRP had superior fatigue life performance both in terms of stress handled and total cycles to failure. These fatigue testing data will inform future use of hybrid CFRP materials by highlighting the tradeoff between increased through-thickness TC and fatigue life. Testing guidelines, equipment, and parameters for static and fatigue tests were successfully outlined for CFRPs.

composites↗

Properties of PMR Polyimides Improved by Preparation of Polyhedral Oligomeric Silsesquioxane (POSS) Nanocomposites

The field of hybrid organic-inorganic materials has grown drastically over the last several years. This interest stems from our ever-increasing ability to custom-build and control molecular structure at several length scales. This ability to control both the composition and structure of hybrid materials is sometimes broadly referred to as nanocomposite systems. One class of hybrid (organic-inorganic) nanostructured material is polyhedral oligomeric silsesquioxane (POSS), shown in the preceding diagram. The hybrid composition gives POSS materials dramatically enhanced properties relative to traditional hydrocarbons and inorganics. An important benefit of this technology is that it makes possible the formulations of nanostructured chemicals with excellent thermal and oxidative stability. This is largely due to the inorganic component.

Campbell, Sandi G.↗

Additive Manufacturing: Disrupting Global Supply Chains and Enabling Sustainable Development

The integration of new materials and innovative manufacturing technologies into product supply chains are critically needed to address human and societal needs and to promote sustainable development and economic competitiveness. Recently, there has been tremendous growth in the additive manufacturing (AM) landscape with the introduction of high- end machines suitable for industrial applications. In addition, availability of desktop 3-D printers as well as open source printers and platforms have also facilitated the large scale growth of distributed manufacturing. The paradigm shift in thinking, where one can turn their design into product on demand, is leading to new business models and challenging traditional models of product development and distribution. In this presentation, an overview of different AM technologies will be provided along with technical challenges and opportunities. Various examples of materials (polymers, ceramics, metals, hybrids, and multi material systems) and structures achieved from utilizing a wide variety of additive manufacturing approaches will be provided. Technical challenges and opportunities for the utilization of additive manufacturing as a powerful enabler for sustainable development and disruptive technological threat to global supply chains for different materials and systems will be presented.

Additive Manufacturing↗

Preliminary burn and impact tests of hybrid polymeric composites

Free graphite fibers released into the environment from resin matrix composite components, as a result of fire and/or explosion, pose a potential hazard to electrical equipment. An approach to prevent the fibers from becoming airborne is to use hybrid composite materials which retain the fibers at the burn site. Test results are presented for three hybrid composites that were exposed to a simulation of an aircraft fire and explosion. The hybrid systems consisted of 16 plies of graphite-epoxy with two plies of Kevlar-, S-glass-, or boron-epoxy on each face. Two different test environments were used. In one environment, specimens were heated by convection only, and then impacted by a falling mass. In the other environment, specimens were heated by convection and by radiation, but were not impacted. The convective heat flux was about 100-120 kW/m in both environments and the radiative flux was about 110 kW/sq m.

Tompkins, S. S.↗

Hybrid Multifoil Aerogel Thermal Insulation

This innovation blends the merits of multifoil insulation (MFI) with aerogel-based insulation to develop a highly versatile, ultra-low thermally conductive material called hybrid multifoil aerogel thermal insulation (HyMATI). The density of the opacified aerogel is 240 mg/cm3 and has thermal conductivity in the 20 mW/mK range in high vacuum and 25 mW/mK in 1 atmosphere of gas (such as argon) up to 800 C. It is stable up to 1,000 C. This is equal to commercially available high-temperature thermal insulation. The thermal conductivity of the aerogel is 36 percent lower compared to several commercially available insulations when tested in 1 atmosphere of argon gas up to 800 C.

Sakamoto, Jeffrey↗

Dry Process for Manufacturing Hybridized Boron Fiber/Carbon Fiber Thermoplastic Composite Materials from a Solution Coated Precursor

An apparatus for producing a hybrid boron reinforced polymer matrix composite from precursor tape and a linear array of boron fibers. The boron fibers are applied onto the precursor tapes and the precursor tape processed within a processing component having an impregnation bar assembly. After passing through variable-dimension forming nip-rollers, the precursor tape with the boron fibers becomes a hybrid boron reinforced polymer matrix composite. A driving mechanism is used to pulled the precursor tape through the method and a take-up spool is used to collect the formed hybrid boron reinforced polymer matrix composite.

Harry L Belvin↗

Hybrid rocket fuel combustion and regression rate study

The objectives of this study are to develop hybrid fuels (1) with higher regression rates and reduced dependence on fuel grain geometry and (2) that maximize potential specific impulse using low-cost materials. A hybrid slab window motor system was developed to screen candidate fuels - their combustion behavior and regression rate. Combustion behavior diagnostics consisted of video and high speed motion pictures coverage. The mean fuel regression rates were determined by before and after measurements of the fuel slabs. The fuel for this initial investigation consisted of hydroxyl-terminated polybutadiene binder with coal and aluminum fillers. At low oxidizer flux levels (and corresponding fuel regression rates) the filled-binder fuels burn in a layered fashion, forming an aluminum containing binder/coal surface melt that, in turn, forms into filigrees or flakes that are stripped off by the crossflow. This melt process appears to diminish with increasing oxidizer flux level. Heat transfer by radiation is a significant contributor, producing the desired increase in magnitude and reduction in flow dependency (power law exponent) of the fuel regression rate.

Strand, L. D.↗

Influence of Material Distribution on Impact Resistance of Hybrid Composites

Impact events occur in a wide variety of circumstances. A typical example is a bullet impacting a target made of composite material. These impact events produce time-varying loads on a structure that can result in damage. As a first step to understanding the damage resistance issue in composite laminates, an accurate prediction of the transient response during an impact event is necessary. The analysis of dynamic loadings on laminated composite plates has undergone considerable development recently. Rayleigh-Ritz energy method was used to determine the impact response of laminated plates. The impact response of composite plates using shear deformation plate theory was analyzed. In recent work a closed-form solution was obtained for a rectangular plate with four edges simply supported subjected to a center impact load using classical plate theory. The problem was further investigated and the analysis results compared of both classical plate theory and shear deformation theory, and found that classical plate theory predicts very accurate results for the range of small deformations considered. In this study, the influence of cross sectional material distribution on the comparative impact responses of hybrid metal laminates subjected to low and medium velocity impacts is investigated. A simple linear model to evaluate the magnitude of the impact load is proposed first, and it establishes a relation between the impact velocity and the impact force. Then a closed-form solution for impact problem is presented. The results were compared with the finite element analysis results. For an 11 layer-hybrid laminate, the impact response as a function of material distribution in cross-section is presented. With equal areal weight, the effect of the number of laminate layers on the impact resistance is also investigated. Finally, the significance of the presented results is discussed.

Abatan, Ayu↗

Additive Manufacturing of Multi-Material Systems for Aerospace Applications

Additive manufacturing methods for producing single materials are rapidly improving. The resulting material properties and microstructures are becoming more comparable to those of conventionally fabricated materials. However, the need for multi-functional and complex structures and components requires additional innovations in manufacturing such as multi-material and hybrid additive manufacturing approaches. Additive manufacturing machines with multiple print capabilities and combinations of AM, machining, and conventional processing methods will further open up design spaces and possibilities. In this presentation, several examples of the needs and methods for multi-material fabrication will be discussed with a focus on aerospace applications. Direct printing of silver coils in conjunction with fused deposition modeling, machined parts, and, binder jetting is being developed for innovative stator designs. Binder jetting of silicon-based materials with powder bed additions is being developed for heat exchanger applications. Additive manufacturing of bi-material systems is being pursued to fabricate lightweight, integrated, multifunctional structures.

multi-materials↗

High Voltage Hybrid Electric Propulsion - Multilayered Functional Insulation System (MFIS) NASA-GRC

High power transmission cables pose a key challenge in future Hybrid Electric Propulsion Aircraft. The challenge arises in developing safe transmission lines that can withstand the unique environment found in aircraft while providing megawatts of power. High voltage AC, variable frequency cables do not currently exist and present particular electrical insulation challenges since electrical arcing and high heating are more prevalent at higher voltages and frequencies. Identifying and developing materials that maintain their dielectric properties at high voltage and frequencies is crucial.

Power distribution↗

Contamination control in hybrid microelectronic modules. Part 2: Selection and evaluation of coating materials

The selection, test, and evaluation of organic coating materials for contamination control in hybrid circuits is reported. The coatings were evaluated to determine their suitability for use as a conformal coating over the hybrid microcircuit (including chips and wire bonds) inside a hermetically sealed package. Evaluations included ease of coating application and repair and effect on thin film and thick film resistors, beam leads, wire bonds, transistor chips, and capacitor chips. The coatings were also tested for such properties as insulation resistance, voltage breakdown strength, and capability of immobilizing loose particles inside the packages. The selected coatings were found to be electrically, mechanically, and chemically compatible with all components and materials normally used in hybrid microcircuits.

Himmel, R. P.↗

Advanced Materials Development under NASA’s Hybrid Thermally Efficient Core (HyTEC) Project

The Hybrid Thermally Efficient Core (HyTEC) project aims to develop small core turbofan engine technologies that will enable fuel burn reductions, additional use of electric airplane systems through power extraction, and to advance engine operability and compatibility with sustainable aviation fuels. As such, a portfolio of technologies that contribute to raising the pressure, temperature and efficiency of turbofan engine cores needs developed. Included in HyTEC’s technology portfolio to enable these advancements are enhanced combustor liner materials and higher temperature capable turbine blades and vanes manufactured using ceramic matrix composites (CMCs) and environmental barrier coatings (EBCs). These technologies are being developed and tested in laboratory-scale relevant environments to advance the technology readiness level (TRL) to 4 or 5, before moving into an engine core demonstrator to raise the TRL to 6. A new natural gas/oxygen burner rig facility will be used to simulate turbine engine relevant environments at the laboratory/coupon scale. In addition, improvements to enable sub-element, and more complex component testing in NASA Glenn’s combustor facility (CE-5) will be presented.

Ceramic Matrix Composites (CMCs)↗

Spherical Cryogenic Hydrogen Tank Preliminary Design Trade Studies

A structural analysis, sizing optimization, and weight prediction study was performed by Collier Research Corporation and NASA Glenn on a spherical cryogenic hydrogen tank. The tank consisted of an inner and outer wall separated by a vacuum for thermal insulation purposes. HyperSizer (Collier Research and Development Corporation), a commercial automated structural analysis and sizing software package was used to design the lightest feasible tank for a given overall size and thermomechanical loading environment. Weight trade studies were completed for different panel concepts and metallic and composite material systems. Extensive failure analyses were performed for each combination of dimensional variables, materials, and layups to establish the structural integrity of tank designs. Detailed stress and strain fields were computed from operational temperature changes and pressure loads. The inner tank wall is sized by the resulting biaxial tensile stresses which cause it to be strength driven, and leads to an optimum panel concept that need not be stiffened. Conversely, the outer tank wall is sized by a biaxial compressive stress field, induced by the pressure differential between atmospheric pressure and the vacuum between the tanks, thereby causing the design to be stability driven and thus stiffened to prevent buckling. Induced thermal stresses become a major sizing driver when a composite or hybrid composite/metallic material systems are used for the inner tank wall for purposes such as liners to contain the fuel and reduce hydrogen permeation.

Arnold, Steven M.↗

Carbon/graphite composite material study. Appendix C: NASA studies on modification of carbon/graphite fibers and alternative materials

The feasibility of modifying resin matrix composites to reduce the potential of electrical shorting from fire released fiber was explored. The effort included modifications to or coatings for graphite fibers, alternative fibers, modifications to matrix materials, and hybrid composites. The objectives included reduction of the conductivity of the graphite fiber, char formation to reduce fiber release, glass formation to prevent fiber release, catalysis to assure fiber consumption in a fire, and replacement of the graphite fibers with nonconductive fibers of similar mechanical potential.

Source record↗

Large, horizontal-axis wind turbines

Development of the technology for safe, reliable, environmentally acceptable large wind turbines that have the potential to generate a significant amount of electricity at costs competitive with conventional electric generating systems are presented. In addition, these large wind turbines must be fully compatible with electric utility operations and interface requirements. There are several ongoing large wind system development projects and applied research efforts directed toward meeting the technology requirements for utility applications. Detailed information on these projects is provided. The Mod-O research facility and current applied research effort in aerodynamics, structural dynamics and aeroelasticity, composite and hybrid composite materials, and multiple system interaction are described. A chronology of component research and technology development for large, horizontal axis wind turbines is presented. Wind characteristics, wind turbine economics, and the impact of wind turbines on the environment are reported. The need for continued wind turbine research and technology development is explored. Over 40 references are sited and a bibliography is included.

Linscott, B. S.↗

Hybrid aerogel rigid ceramic fiber insulation and method of producing same

A hybrid insulation material comprises of porous ceramic substrate material impregnated with nanoporous material and method of making the same is the topic of this invention. The porous substrate material has bulk density ranging from 6 to 20 lb/ft.sup.3 and is composed of about 60 to 80 wt % silica (SiO.sub.2) 20 to 40 wt % alumina (Al.sub.2 O.sub.3) fibers, and with about 0.1 to 1.0 wt % boron-containing constituent as the sintering agent. The nanoporous material has density ranging from 1.0 to 10 lb/ft.sup.3 and is either fully or partially impregnated into the substrate to block the pores, resulting in substantial reduction in conduction via radiation and convention. The nanoporous material used to impregnate the fiber substrate is preferably formed from a precursor of alkoxysilane, alcohol, water, and an acid or base catalyst for silica aerogels, and from a precursor of aluminum alkoxide, alcohol, water, and an acid or base catalyst for alumina aerogels.

Barney, Andrea O.↗