Design and Experimental Evaluation of a Light-weight Turbine-wheel Assembly
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Morgan, W C↗
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Results for “Light Weight”
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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Design and Experimental Investigation of Light-weight Bases for Air-cooled Turbine Rotor Blades
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Freche, John C↗
Genetic algorithms in conceptual design of a light-weight, low-noise, tilt-rotor aircraft
This report outlines research accomplishments in the area of using genetic algorithms (GA) for the design and optimization of rotorcraft. It discusses the genetic algorithm as a search and optimization tool, outlines a procedure for using the GA in the conceptual design of helicopters, and applies the GA method to the acoustic design of rotors.
Wells, Valana L.↗
Genetic algorithms in conceptual design of a light-weight, low-noise, tilt-rotor aircraft
This report outlines research accomplishments in the area of using genetic algorithms (GA) for the design and optimization of rotorcraft. It discusses the genetic algorithm as a search and optimization tool, outlines a procedure for using the GA in the conceptual design of helicopters, and applies the GA method to the acoustic design of rotors.
Wells, Valana L.↗
Manufacturing Challenges Implementing Material Changes for the Super Light Weight External Tank: A Welding Process Perspective
A viewgraph presentation gives an overview of the manufacturing challenges in implementing welding material changes for the super lightweight external tank. Details are given on the external tank configuration, the weld purging equipment used, planning the selection of weld filler wire alloy, the initial weld microstructure, the wide panel tensile testing, and the dome cap welding.
Lawless, K.↗
Light Weight Long Life Materials and Structures
High performance materials are enabling or enhancing for numerous engine/vehicle concepts and are critical to meeting safety, cost, and performance goals. A subproject covers polymeric, metallic, and ceramic high temperature materials for rocket propulsion systems. Projects will also include a wide variety of efforts with some fundamental work with late maturity dates.
Glasgow, Tom↗
Design and Development of Thin Plastic Foil, Conical Approximation, High Through-out X-Ray Telescope: Light Weight, Thin Plastic Foil, X-Ray Telescopes
We present results from a program to develop an X-ray telescope made from thin plastic shells. Our initial results have been obtained from multi-shell cylindrical lenses that are used in a point-to-point configuration to image the small focal spot of a an X-ray tube on a microchannel plate detector. We describe the steps that led up to the present design and present data from the tests that have been used to identify the properties of the plastic material that make it a suitable X-ray reflector. We discuss two applications of our technology to X-ray missions that are designed to address some of the scientific priorities set forth in NASA's long term plans for high energy astrophysics. One mission will observe in the 1 - 10 keV band, the other will extend up to ca. 100 keV.
Schnopper, Herbert W.↗
The Series Connected Buck Boost Regulator Concept for High Efficiency Light Weight DC Voltage Regulation
Improvements in the efficiency and size of DC-DC converters have resulted from advances in components, primarily semiconductors, and improved topologies. One topology, which has shown very high potential in limited applications, is the Series Connected Boost Unit (SCBU), wherein a small DC-DC converter output is connected in series with the input bus to provide an output voltage equal to or greater than the input voltage. Since the DC-DC converter switches only a fraction of the power throughput, the overall system efficiency is very high. But this technique is limited to applications where the output is always greater than the input. The Series Connected Buck Boost Regulator (SCBBR) concept extends partial power processing technique used in the SCBU to operation when the desired output voltage is higher or lower than the input voltage, and the implementation described can even operate as a conventional buck converter to operate at very low output to input voltage ratios. This paper describes the operation and performance of an SCBBR configured as a bus voltage regulator providing 50 percent voltage regulation range, bus switching, and overload limiting, operating above 98 percent efficiency. The technique does not provide input-output isolation.
Birchenough, Arthur G.↗
Light Weight Biomorphous Cellular Ceramics from Cellulose Templates
Bimorphous ceramics are a new class of materials that can be fabricated from the cellulose templates derived from natural biopolymers. These biopolymers are abundantly available in nature and are produced by the photosynthesis process. The wood cellulose derived carbon templates have three- dimensional interconnectivity. A wide variety of non-oxide and oxide based ceramics have been fabricated by template conversion using infiltration and reaction-based processes. The cellular anatomy of the cellulose templates plays a key role in determining the processing parameters (pyrolysis, infiltration conditions, etc.) and resulting ceramic materials. The processing approach, microstructure, and mechanical properties of the biomorphous cellular ceramics (silicon carbide and oxide based) have been discussed.
Singh, Mrityunjay↗
Light Weight Design Nickel-Alkaline Cells Using Fiber Electrodes
Using fiber electrode technology, currently produced by Bekaert Corporation (Bekaert), Electro Energy, Inc., (EEI) Mobile Energy Products Group (formerly, Eagle-Picher Technologies, LLC., Power Systems Department) in Colorado Springs, CO has demonstrated that it is feasible to manufacture flight weight nickel-hydrogen cells having about twice the specific energy (80 vs. 40 watt-hr/kg) as state-of-the-art nickel-hydrogen cells that are flown on geosynchronous communications satellites. Although lithium-ion battery technology has made large in-roads to replace the nickel-alkaline technology (nickel-cadmium, nickel-metal hydride), the technology offered here competes with lithium-ion weight and offers alternatives not present in the lithium-ion chemistry such as ability to undergo continuous overcharge, reversal on discharge and sustain rate capability sufficient to start automotive and aircraft engines at subzero temperatures. In development to date seven 50 ampere-hour nickel-hydrogen have been constructed, acceptance tested and briefly tested in a low earth orbit (LEO) cycle regime. The effort was jointly funded by Electro Energy, Inc. and NASA Glenn Research Center, Cleveland, OH. Five of the seven cells have been shipped to NASA GRC for further cycle testing. Two of the cells experienced failure due to internal short circuits during initial cycle testing at EEL Destructive Physical Analysis (DPA) of one of the cells has shown the failure mode to be due to inadequate hydrogen catalyst electrodes that were not capacity balanced with the higher energy density nickel oxide electrodes. In the investigators opinion, rebuild of the cells using proper electrode balance would result in cells that could sustain over 30,000 cycles at moderate depths-of-discharge in a LEO regime or endure over 20 years of geosynchronous orbit (GEO) cycling while realizing a two-fold increase in specific energy for the battery or a 1.1 kg weight savings per 50 ampere-hour cell. Additional information is included in the original extended abstract.
Pickett, David F.↗
A Light-Weight Inflatable Hypersonic Drab Device for Venus Entry
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Inflatable hypersonic Venus Entry↗
Performance of a Light-Weight Ablative Thermal Protection Material for the Stardust Mission Sample Return Capsule
New tests and analyses are reported that were carried out to resolve testing uncertainties in the original development and qualification of a lightweight ablative material used for the Stardust spacecraft forebody heat shield. These additional arcjet tests and analyses confirmed the ablative and thermal performance of low density Phenolic Impregnated Carbon Ablator (PICA) material used for the Stardust design. Testing was done under conditions that simulate the peak convective heating conditions (1200 W/cm2 and 0.5 atm) expected during Earth entry of the Stardust Sample Return Capsule. Test data and predictions from an ablative material response computer code for the in-depth temperatures were compared to guide iterative adjustment of material thermophysical properties used in the code so that the measured and predicted temperatures agreed. The PICA recession rates and maximum internal temperatures were satisfactorily predicted by the computer code with the revised properties. Predicted recession rates were also in acceptable agreement with measured rates for heating conditions 37% greater than the nominal peak heating rate of 1200 W/sq cm. The measured in-depth temperature response data show consistent temperature rise deviations that may be caused by an undocumented endothermic process within the PICA material that is not accurately modeled by the computer code. Predictions of the Stardust heat shield performance based on the present evaluation provide evidence that the maximum adhesive bondline temperature will be much lower than the maximum allowable of 250 C and an earlier design prediction. The re-evaluation also suggests that even with a 25 percent increase in peak heating rates, the total recession of the heat shield would be a small fraction of the as-designed thickness. These results give confidence in the Stardust heat shield design and confirm the potential of PICA material for use in new planetary probe and sample return applications.
Covington, M. A.↗
Light weight polymer matrix composite material
A graphite fiber reinforced polymer matrix is layed up, cured, and thermally aged at about 750.degree. F. in the presence of an inert gas. The heat treatment improves the structural integrity and alters the electrical conductivity of the materials. In the preferred embodiment PMR-15 polyimides and Celion-6000 graphite fibers are used.
Bowles, Kenneth J.↗
High Conductivity Carbon-Carbon Heat Pipes for Light Weight Space Power System Radiators
Based on prior successful fabrication and demonstration testing of a carbon-carbon heat pipe radiator element with integral fins this paper examines the hypothetical extension of the technology via substitution of high thermal conductivity composites which would permit increasing fin length while still maintaining high fin effectiveness. As a result the specific radiator mass could approach an ultimate asymptotic minimum value near 1.0 kg/m2, which is less than one fourth the value of present day satellite radiators. The implied mass savings would be even greater for high capacity space and planetary surface power systems, which may require radiator areas ranging from hundreds to thousands of square meters, depending on system power level.
Juhasz, Albert J.↗
Next Generation Astronomical X-ray Optics: High Angular Resolution, Light Weight, and Low Production Cost
X-ray astronomy depends on the availability of telescopes with high resolution and large photon collecting areas. Since x-ray observation can only be carried out above the atmosphere, these telescopes must be necessarily lightweight. Compounding the lightweight requirement is that an x-ray telescope consists of many nested concentric shells, which further require that x-ray mirrors must also be geometrically thin to achieve high packing efficiency. This double lightweight and geometrically thin requirement poses significant technical challenges in fabricating the mirrors and in integrating them into mirror assemblies. This paper reports on the approach, strategy and status of our x-ray optics development program whose objective is to meet these technical challenges at modest cost to enable future x-ray missions, including small Explorer missions in the near term, probe class missions in the medium term, and large flagship missions in the long term.
Zhang. W. W.↗
Cryogenic Optical Performance of a Light-weight Mirror Assembly for Future Space Astronomical Telescopes: Optical Test Results and Thermal Optical Model
A 40 cm diameter mirror assembly was interferometrically tested at room temperature down to 250 degrees Kelvin for thermal deformation. The 2.5 m radius of curvature spherical mirror assembly was constructed by low temperature fusing three abrasive waterjet core sections between two face sheets. The 93% lightweighted Corning ULE mirror assembly represents the current state of the art for future UV, optical, near IR space telescopes. During the multiple thermal test cycles, test results of interferometric test, thermal IR images of the front face were recorded in order to validate thermal optical model.
Eng, Ron↗
Low-Cost, Light Weight, Thin Film Solar Concentrator
This research addresses a cost barrier towards achieving a solar thermal collector system with an installed cost of $75/sq m and meet the Department of Energy's (DOE's) performance targets for optical errors, operations during windy conditions and lifetime. Current concentrators can cost as much as 40-50% of the total installed costs for a CSP plant. In order to reduce the costs from current $200-$250/sq m, it is important to focus on the overall system. The reflector surface is a key cost driver, and our film-based polymer reflector will help significantly in achieving DOE's cost target of $75/sq m. The ease of manufacturability, installation and replacement make this technology a compelling one to develop. This technology can be easily modified for a variety of CSP options including heliostats, parabolic dishes and parabolic troughs.
Concentrating Solar Power (CSP)↗