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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 505 records · Page 28

All sources NASA NTRS DOE OSTI

NASA NTRS1988

Thermal Response Of Composite Insulation

Engineering model gives useful predictions. Pair of reports presents theoretical and experimental analyses of thermal responses of multiple-component, lightweight, porous, ceramic insulators. Particular materials examined destined for use in Space Shuttle thermal protection system, test methods and heat-transfer theory useful to chemical, metallurgical, and ceramic engineers needing to calculate transient thermal responses of refractory composites.

Stewart, David A.↗

NASA NTRS1988

P/M aluminum metal matrix composites

Development of lightweight, high specific stiffness engineered materials has been the long term goal of many investigators. Recently, this quest has focused on discontinuously reinforced aluminum metal matrix composites. This paper reviews the fabrication of powder metallurgy discontinuously reinforced metal matrix composites. Emphasis is given to the differences in heat treatment response reported between unreinforced and reinforced powder metallurgy materials. It is proposed that these observations can be rationalized by considering the effects of pre-existing heterogeneous nucleation sites, i.e., the dislocation substructure developed during rapid cooling of discontinuously reinforced aluminum metal matrix composites, on precipitation in reinforced aluminum alloys.

Rack, H. J.↗

NASA NTRS1990

Durable Bipolar Plates For Lead/Acid Batteries

New structure for positive faces of bipolar plates increases longevity of lead/acid batteries. Divides positive-electrode layer into many isolated segments so defects cannot spread across layer. Surfaces treated before assembly to promote adhesion. Ridges on body divide possible electrode into isolated squares, each typically 1 in. on side. Materials supporting electrochemically active components lightweight and resistant to acid.

Clough, Thomas J.↗

NASA NTRS1993

Automated Cutting And Drilling Of Composite Parts

Proposed automated system precisely cuts and drills large, odd-shaped parts made of composite materials. System conceived for manufacturing lightweight composite parts to replace heavier parts in Space Shuttle. Also useful in making large composite parts for other applications. Includes robot locating part to be machined, positions cutter, and positions drill. Gantry-type robot best suited for task.

Warren, Charles W.↗

NASA NTRS1993

Thermal Conductivity And Expansion Of Graphite/Copper

Report describes fabrication of graphite-fiber/copper-matrix composite plates, measurements of thermal conductivities of plates at temperatures from ambient to 1,073 K, and measurements of thermal expansions of plates from ambient temperature to 1,050 K. Composites promising lightweight, high-thermal-conductivity materials proposed for use in heat exchangers and other heat-transfer components of power systems in spacecraft and hypersonic aircraft. Graphite/copper also of interest as model composite material.

Mcdanels, David L.↗

NASA NTRS1992

Extraterrestrial applications of solar optics for interior illumination

Solar optics is a terrestrial technology that has potential extraterrestrial applications. Active solar optics (ASO) and passive solar optics (PSO) are two approaches to the transmission of sunlight to remote interior spaces. Active solar optics is most appropriate for task illumination, while PSO is most appropriate for general illumination. Research into solar optics, motivated by energy conservation, has produced lightweight and low-cost materials, products that have applications to NASA's Controlled Ecological Life Support System (CELSS) program and its lunar base studies. Specifically, prism light guides have great potential in these contexts. Several applications of solar optics to lunar base concepts are illustrated.

Eijadi, David A.↗

NASA NTRS2001

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.↗

NASA NTRS2003

Integrated Propulsion/Vehicle System Structurally Optimized

Ongoing research and testing are essential in the development of air-breathing hypersonic propulsion technology, and this year some positive advancement was made at the NASA Glenn Research Center. Recent work performed for GTX, a rocket-based combined-cycle, single-stage-to-orbit concept, included structural assessments of both the engine and flight vehicle. In the development of air-breathing engine technology, it is impractical to design and optimize components apart from the fully integrated system because tradeoffs must be made between performance and structural capability. Efforts were made to control the flight trajectory, for example, to minimize the aerodynamic heating effects. Structural optimization was applied to evaluate concept feasibility and was instrumental in the determination of the gross liftoff weight of the integrated system. Achieving low Earth orbit with even a small payload requires an aggressive approach to weight minimization through the use of lightweight, oxidation-resistant composite materials. Assessing the integrated system involved investigating the flight trajectory to determine where the critical load events occur in flight and then generating the corresponding environment at each of these events. Structural evaluation requires the mapping of the critical flight loads to finite element models, including the combined effects of aerodynamic, inertial, combustion, and other loads. NASA s APAS code was used to generate aerodynamic pressure and temperature profiles at each critical event. The radiation equilibrium surface temperatures from APAS were used to predict temperatures through the thickness. Heat transfer solutions using NASA's MINIVER code and the SINDA code (Cullimore & Ring Technologies, Littleton, CO) were calculated at selective points external to the integrated vehicle system and then extrapolated over the entire exposed surface. FORTRAN codes were written to expedite the finite element mapping of the aerodynamic heating effects for the internal structure.

Hunter, James E.↗

NASA NTRS2006

Flexible Fabrics with High Thermal Conductivity for Advanced Spacesuits

This paper describes the effort and accomplishments for developing flexible fabrics with high thermal conductivity (FFHTC) for spacesuits to improve thermal performance, lower weight and reduce complexity. Commercial and additional space exploration applications that require substantial performance enhancements in removal and transport of heat away from equipment as well as from the human body can benefit from this technology. Improvements in thermal conductivity were achieved through the use of modified polymers containing thermally conductive additives. The objective of the FFHTC effort is to significantly improve the thermal conductivity of the liquid cooled ventilation garment by improving the thermal conductivity of the subcomponents (i.e., fabric and plastic tubes). This paper presents the initial system modeling studies, including a detailed liquid cooling garment model incorporated into the Wissler human thermal regulatory model, to quantify the necessary improvements in thermal conductivity and garment geometries needed to affect system performance. In addition, preliminary results of thermal conductivity improvements of the polymer components of the liquid cooled ventilation garment are presented. By improving thermal garment performance, major technology drivers will be addressed for lightweight, high thermal conductivity, flexible materials for spacesuits that are strategic technical challenges of the Exploration

Trevino, Luis A.↗

NASA NTRS2011

Development of Passive Fuel Cell Thermal Management Technology

The NASA Glenn Research Center is developing advanced passive thermal management technology to reduce the mass and improve the reliability of space fuel cell systems for the NASA exploration program. The passive thermal management system relies on heat conduction within the cooling plate to move the heat from the central portion of the cell stack out to the edges of the fuel cell stack rather than using a pumped loop cooling system to convectively remove the heat. Using the passive approach eliminates the need for a coolant pump and other cooling loop components which reduces fuel cell system mass and improves overall system reliability. Previous analysis had identified that low density, ultra-high thermal conductivity materials would be needed for the cooling plates in order to achieve the desired reductions in mass and the highly uniform thermal heat sink for each cell within a fuel cell stack. A pyrolytic graphite material was identified and fabricated into a thin plate using different methods. Also a development project with Thermacore, Inc. resulted in a planar heat pipe. Thermal conductivity tests were done using these materials. The results indicated that lightweight passive fuel cell cooling is feasible.

Burke, Kenneth A.↗

NASA NTRS2014

PRSEUS Structural Concept Development

A lighter, more robust airframe is one of the key technological advancements necessary for the successful launch of any large next-generation transport aircraft. Such a premise dictates that considerable improvements beyond current state-of-the-art aluminum structures is needed, and that improvements of this magnitude will require an extensive use of composite materials that are not only lightweight, but also economical to produce. To address this challenge, researchers at NASA and The Boeing Company are developing a novel structural concept called the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) under the Environmentally Responsible Aviation (ERA) Project. It is an integrally stiffened panel concept that is stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. In addition to improved structural performance, an important facet of this unique arrangement of stitched carbon fibers is its innovative manufacturing method that has the potential to lower fabrication costs by eliminating fasteners and autoclave cures. The rationale and development status for this new approach forms the basis of the work described in this paper. The test specimens described herein were fabricated, or are currently being fabricated, by The Boeing Company, while the structural analyses and testing tasks are being performed by NASA and Boeing personnel.

Velicki, Alex↗

NASA NTRS2015

Method for Producing Launch/Landing Pads and Structures Project

Current plans for deep space exploration include building landing-launch pads capable of withstanding the rocket blast of much larger spacecraft that that of the Apollo days. The proposed concept will develop lightweight launch and landing pad materials from in-situ materials, utilizing regolith to produce controllable porous cast metallic foam brickstiles shapes. These shapes can be utilized to lay a landing launch platform, as a construction material or as more complex parts of mechanical assemblies.

Technology Portfolio System↗

NASA NTRS2017

Hybrid Gear Performance Under Loss-of-Lubrication Conditions

Hybrid composite gear technology is being investigated to increase power density in rotorcraft drive systems. These gears differ from conventional steel gears in that the structural web material is replaced with a lightweight carbon fiber composite. Past studies have focused on performance of this technology under normal operating conditions, however, for this technology to be viable it must also withstand adverse conditions. The study presented here evaluates the performance of hybrid gears under loss-of-lubrication conditions in NASA Glenn Research Centers Contact Fatigue Test Facility. Two experiments are presented using small-scale 3.5 inch (8.9 cm) pitch diameter hybrid gears and compared to a baseline steel gear pair. Results of these tests show that there are limitations to the use of a hexagonal interlock pattern between the steel and composite. There is also evidence that the presence of polymer in the gear during an oil out event has a potential to increase time to failure. Further studies are planned to expand on these initial findings.

Gearbox↗

NASA NTRS2017

Hybrid Gear Performance Under Loss-of-Lubrication Conditions

Gearbox↗

DOE OSTI2021

Fabrication of Flexible Perovskite Solar Cells via Rapid Thermal Annealing

Adaptability, lightweight, and low cost of materials make flexible perovskite solar cells essential for the perovskite technology to breach commercial photovoltaic market. Roll-to-roll manufacturing has great potential for high-throughput perovskite manufacturing; however, conventional annealing methods are not capable of producing flexible perovskite solar cells at scale. Rapid thermal annealing (RTA), a radiative method, is utilized on roll-to-roll lines within many different industries and has shown promising potential for perovskite annealing. Here, we introduce a blade-coated perovskite thin film on flexible ITO-coated PET annealed via RTA that reduces post-deposition processing time from ~150 seconds to ~14 seconds. Performance was not sacrificed for scalability as a perovskite solar cell was produced with a power conversion efficiency (PCE) of 14.58%.

Martin, Blake↗

NASA NTRS2019

High-Resolution, Lightweight, and Low-cost X-Ray Optics for the Lynx Observatory

We describe an approach to build an x-ray mirror assembly that can meet Lynx’s requirements of high-angular resolution, large effective area, light weight, short production schedule, and low-production cost. Adopting a modular hierarchy, the assembly is composed of 37,492 mirror segments, each of which measures ∼100 mm × 100 mm × 0.5 mm. These segments are integrated into 611 modules, which are individually tested and qualified to meet both science performance and spaceflight environment requirements before they in turn are integrated into 12 metashells. The 12 metashells are then integrated to form the mirror assembly. This approach combines the latest precision polishing technology and the monocrystalline silicon material to fabricate the thin and lightweight mirror segments. Because of the use of commercially available equipment and material and because of its highly modular and hierarchical building-up process, this approach is highly amenable to automation and mass production to maximize production throughput and to minimize production schedule and cost. As of fall 2018, the basic elements of this approach, including substrate fabrication, coating, alignment, and bonding, have been validated by the successful building and testing of single-pair mirror modules. In the next few years, the many steps of the approach will be refined and perfected by repeatedly building and testing mirror modules containing progressively more mirror segments to fully meet science performance, spaceflight environments, as well as programmatic requirements of the Lynx mission and other proposed missions, such as AXIS.

Zhang, William W.↗

NASA NTRS1960

VII. Some structual and materials considerations for manned military aircraft

The design of lightweight, efficient structures is one of the fundamental requirements for achievement of high performance in military aircraft. In this paper some of the structural and materials considerations that are important to the strength, weight, and integrity of aircraft structures are reviewed. A comparison of some structural materials is made on the basis of weight-strength and tear resistance. In the area of structural design, the relative weights of several types of construction that are of current interest are reviewed and the influence of different materials and the effects of the related temperatures on structural weight are indicated. Lastly, other factors that are of importance in structural design of future aircraft are discussed. These include strength under nonuniform temperatures, creep, sonic fatigue, and panel flutter.

Structural material↗

NASA NTRS1975

On development of an inexpensive, lightweight thermal micrometeroid garment for space suits

A lightweight and inexpensive coverlayer developed for space suits is described. Material selection, procurement, and testing, pattern design, and prototype fabrication are discussed. By using the minimum required cross section necessary for earth orbital mission, by utilizing the lightest weight materials possible, and by decreasing the use of weight costly taping a lightweight and economical thermal micrometeroid garment was developed. Simplification of manufacturing techniques and use of off-the-shelf materials helped to reduce costs.

Source record↗