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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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NASA NTRS1980

Regional price targets appropriate for advanced coal extraction

A methodology is presented for predicting coal prices in regional markets for the target time frames 1985 and 2000 that could subsequently be used to guide the development of an advanced coal extraction system. The model constructed is a supply and demand model that focuses on underground mining since the advanced technology is expected to be developed for these reserves by the target years. Coal reserve data and the cost of operating a mine are used to obtain the minimum acceptable selling price that would induce the producer to bring the mine into production. Based on this information, market supply curves can be generated. Demand by region is calculated based on an EEA methodology that emphasizes demand by electric utilities and demand by industry. The demand and supply curves are then used to obtain the price targets. The results show a growth in the size of the markets for compliance and low sulphur coal regions. A significant rise in the real price of coal is not expected even by the year 2000. The model predicts heavy reliance on mines with thick seams, larger block size and deep overburden.

Terasawa, K. L.↗
NASA NTRS2010

Environmentally Responsible Aviation - Real Solutions for Environmental Challenges Facing Aviation

The combined reality of persistently strong growth in air traffic and the vital economic role of the air transport system result in continued demand for the progress of technology for the reduction of aircraft noise, emissions of oxides of nitrogen, and fuel burn. NASA s Environmentally Responsible Aviation (ERA) project has set aggressive goals in these three areas including a noise goal of 42 dB cumulative below the Stage 4 certification level. The goal for the reduction of oxides of nitrogen is 75% below the current standard. The fuel burn reduction goal is 50% below that of a current state-of-the-art aircraft. Furthermore, the overall goal of ERA is to mature technologies that will meet these goals simultaneously and with a timeframe of 2020 for technical readiness. This paper outlines the key technologies and the progress achieved to date toward the goals.

Collier, Fayette↗
NASA NTRSDate not supplied

Designing for Advanced Aerial Mobility: Human-Autonomy Teaming and In-Time System-Wide Safety Assurance

The continued growth of aviation shall require new innovative technologies and operational concepts to meet the ever-increasing demands on air transportation. The NASA Advanced Air Mobility (AAM) project focuses on emerging aviation markets, such as Urban Air Mobility (UAM). UAM is defined as “...a safe and efficient system for air passenger and cargo transportation within an urban area. It is inclusive of small package delivery and other urban unmanned aerial system services and supports a mix of onboard/ground-piloted and increasingly autonomous operations” ([1]). The AAM project emphasizes technology development and validating system-level concepts and solutions in coordination with other NASA Aeronautics Research Mission Directorate (ARMD) projects to enable UAM metro- and micro-plex vertiport and airspace concepts of operations. The NASA AAM research portfolio includes the concepts of Remote Supervisor-in-Command (RSC) and Fleet and Airspace Manager (FAM) as possible human roles for consumer fleet providers. NASA research in RSC is focused on development of guidelines and standards for remote pilots/operators passively and actively controlling a large fleet of autonomous aircraft. For FAM, flight and ground system concepts and technologies to enable high density homogeneous operations at increased scale from vertiport(s), and coordination with other humans in the systems (e.g., UAM urban airspace manager, Air Traffic Control) are key research areas. The envisioned UAM operations are posited to require autonomous systems to enable functions ranging from fleet and resource management to vehicle control. Although automation has become increasingly sophisticated and ubiquitous in civil aviation, autonomy represents a significant evolution in automation, which has generally been limited in functional scope and capability. As autonomy takes on increasing responsibilities, humans and machines will be required to work together in new and different ways [2], rather than traditional design approaches focused on how machines (i.e., autonomy) can do the work of people. The emerging field of human-autonomy teaming (HAT) represents a comprehensive and prioritized research-driven approach to enable the success of future emerging aviation market applications through capabilities and principles that facilitate humans and machine working and thinking better together. The NASA Transformational Tools and Technologies (TTT) Autonomous System (AS) Sub-project was created to assist with the transition into higher levels of autonomy to enable new modes of air transportation, such as UAM. TTT-AS has identified HAT as a key research need to enable UAM while maintaining today’s ultra-safe aviation system safety levels. The latter challenge has been taken up by the NASA System-Wide Safety (SWS) Project, which recognizes that aviation safety, as it evolves, shall require new ways of thinking about safety to include integration of a wide-range of existing and new safety systems and practices, enhanced tools and technologies, increased access to data and data fusion, improved data analysis capabilities, enhanced in-time risk monitoring and detection, hazard prioritization and mitigation, safety assurance decision-support, and in-time integrated system analytics [3].The operational concept of UAM represents a variety of work that has been termed, “work-as-imagined” to characterize the idea that how people think that work is done and how work is actually done are often not the same [4]. To ensure design success and system safety, looking at “work-as-done” provides a comparative approach toward UAM concept and technology design through examination of corresponding analogs found today in aviation (e.g., on-demand operations) and other transportation domains (e.g., port operations). The paper shall discuss various alternative applications with specific focus on airline operation center (AOC) operations, and unmanned aerial system (UAS) command-and-control to inform scaled-versions of FAM and RSC, respectively, and with consideration of the national airspace system contextual environment. The tenets and principles of the HAT field and current NASA research efforts under the TTT-AS sub-project shall also be described. Finally, the SWS sub-project efforts to develop In-Time System-Wide Safety Assurance (ISSA) and In-Time Safety Management Systems (IASMS) are discussed in terms of how “in-time” safety assurance may be conceptualized for the on-demand mobility air taxi “work-as-imagined” operational concept [5]. As part of this effort, concepts from the emerging field of resilience engineering, are being studied. Traditional approaches to aviation safety have focused on what can go wrong and how to prevent it. Another approach to thinking about system safety should reflect not only “avoiding things that go wrong” (protective safety) but also “ensuring that things go right” (productive safety), that enables a system to exhibit the resilient performance [6] necessary for the success of the future aviation system emerging concepts of operations. The paper shall describe efforts focused on how productive safety and resilience may enable a more complete approach to system safety thinking and design of ISSA and IASMS for UAM. Future directions and research needs shall also be discussed.

resilience↗
NASA NTRS1999

NASGRO 3.0: A Software for Analyzing Aging Aircraft

Structural integrity analysis of aging aircraft is a critical necessity in view of the increasing numbers of such aircraft in general aviation, the airlines and the military. Efforts are in progress by NASA, the FAA and the DoD to focus attention on aging aircraft safety. The present paper describes the NASGRO software which is well-suited for effectively analyzing the behavior of defects that may be found in aging aircraft. The newly revised Version 3.0 has many features specifically implemented to suit the needs of the aircraft community. The fatigue crack growth computer program NASA/FLAGRO 2.0 was originally developed to analyze space hardware such as the Space Shuttle, the International Space Station and the associated payloads. Due to popular demand, the software was enhanced to suit the needs of the aircraft industry. Major improvements in Version 3.0 are the incorporation of the ability to read aircraft spectra of unlimited size, generation of common aircraft fatigue load blocks, and the incorporation of crack-growth models which include load-interaction effects such as retardation due to overloads and acceleration due to underloads. Five new crack-growth models, viz., generalized Willenborg, modified generalized Willenborg, constant closure model, Walker-Chang model and the deKoning-Newman strip-yield model, have been implemented. To facilitate easier input of geometry, material properties and load spectra, a Windows-style graphical user interface has been developed. Features to quickly change the input and rerun the problem as well as examine the output are incorporated. NASGRO has been organized into three modules, the crack-growth module being the primary one. The other two modules are the boundary element module and the material properties module. The boundary-element module provides the ability to model and analyze complex two-dimensional problems to obtain stresses and stress-intensity factors. The material properties module allows users to store and curve-fit fatigue-crack growth data. On-line help and documentation are provided for each of the modules. In addition to the popular PC windows version, a unix-based X-windows version of NASGRO is also available. A portable C++ class library called WxWindows was used to facilitate cross-platform availability of the software.

Mettu, S. R.↗
NASA NTRS2022

Impact of Growth Phase, Pigment Adaptation, and Climate Change Conditions on the Cellular Pigment and Carbon Content of Fifty‐One Phytoplankton Isolates

Owing to their importance in aquatic ecosystems, the demand for models that estimate phytoplankton biomass and community composition in the global ocean has increased over the last decade. Moreover, the impacts of climate change, including elevated carbon dioxide (CO2), increased stratification, and warmer sea surface temperatures, will likely shape phytoplankton community composition in the global ocean. Chemotaxonomic methods are useful for modeling phytoplankton community composition from marker pigments normalized to chlorophyll a (Chl a). However, photosynthetic pigments, particularly Chl a, are sensitive to nutrient and light conditions. Cellular carbon is less sensitive, so using carbon biomass instead may provide an alternative approach. To this end, cellular pigment and carbon concentrations were measured in 51 strains of globally relevant, cultured phytoplankton. Pigment-to-Chl a and pigment-to-carbon ratios were computed for each strain. For 25 strains, measurements were taken during two growth phases. While some differences between growth phases were observed, they did not exceed within class differences. Multiple strains of Amphidinium carterae, Ditylum brightwellii and Heterosigma akashiwo were measured to determine whether time in culture influenced pigment and carbon composition. No appreciable trends in cellular pigment or carbon content were observed. Lastly, the potential impact of climate change conditions on the pigment ratios was assessed using a multistressor experiment that included increased mean light, temperature, and elevated pCO2 on three species: Thalassiosira oceanica, Ostreococcus lucimarinus, and Synechococcus. The largest differences were observed in the pigment-to-carbon ratios, while the marker pigments largely covaried with Chl a. The implications of these observations to chemotaxonomic applications are discussed.

Pigments↗
NASA NTRS1981

Worldwide satellite market demand forecast

The forecast is for the years 1981 - 2000 with benchmark years at 1985, 1990 and 2000. Two typs of markets are considered for this study: Hardware (worldwide total) - satellites, earth stations and control facilities (includes replacements and spares); and non-hardware (addressable by U.S. industry) - planning, launch, turnkey systems and operations. These markets were examined for the INTELSAT System (international systems and domestic and regional systems using leased transponders) and domestic and regional systems. Forecasts were determined for six worldwide regions encompassing 185 countries using actual costs for existing equipment and engineering estimates of costs for advanced systems. Most likely (conservative growth rate estimates) and optimistic (mid range growth rate estimates) scenarios were employed for arriving at the forecasts which are presented in constant 1980 U.S. dollars. The worldwide satellite market demand forecast predicts that the market between 181 and 2000 will range from $35 to $50 billion. Approximately one-half of the world market, $16 to $20 billion, will be generated in the United States.

Bowyer, J. M.↗
NASA NTRS1981

Nuclear Electric Propulsion - A concept for solar system exploration

The potential of Nuclear Electric Propulsion (NEP) to meet the increasing demands of our planetary space exploration program is examined and evaluated. Based on an assumption of a modest growth beyond current technology, an NEP system is described that provides performance advantage over all competitive technologies. Flight times and available payload mass - as indicators of mission performance - are compared for several mission opportunities of interest. NEP is shown to have a unique capacity for substantial reductions in mission flight times in terms of payloads consistent with the needs of planetary exploration.

Nagorski, R. P.↗
NASA NTRS1984

Shuttle/Centaur Upper Stage Capability

A joint project to design, develop, procure, and produce Centaur upper stages for use with the Space Shuttle is discussed. A common Centaur G stage 6 meters (19.5 feet) in length is being jointly developed. A longer version designated Centaur G Prime is being developed by NASA to accomplish the Galileo and International Solar-Polar Mission flights in 1986. The Centaur G and G Prime will have the capability to place, respectively, approximately 4540 kilograms (10,000 pounds) and 5910 kilograms (13,000 pounds) into geosynchronous orbit from a standard Shuttle parking orbit of 278 kilometers (150 nautical miles) and Shuttle performance (lift) capability 29,500 kilograms (65,000 pounds). The advent of high energy upper stage capability in 1986 will permit space users and spacecraft developers to utilize spacecraft growth, stage combination concepts with storage modules, teleoperator systems, and other mission peculiar devices to satisfy complex mission demands. These capabilities should greatly enhance the usefulness of the space environment and stimulate mission planners toward conception of innovative means to meet ever increasing mission requirements.

Clark, H. J.↗
NASA NTRS1985

Early evolution of the crust-mantle system

Nd isotopic data indicate that most Archean igneous rocks including compositions ranging from komatiite to tonalite are derived from undepleted or depleted upper mantle sources. If sampling is representative, only a few require enriched sources. A major unresolved question is the fate of the material removed from the upper mantle leaving early depleted sources as residue. One possibility is that widespread depletion of the early mantle resulted from a period of early degassing and magmatism. Rare gas isotopic data, in particular 129Xe/130Xe ratios, seem to demand that the upper mantle was extensively degassed at or before 4.4 b.y. and this led to rapid growth of the atmosphere and oceans. The lower mantle, however, was not significantly degassed during this event. It is likely that such widespread degassing and magmatism of the upper mantle transferred significant quantities of incompatible elements into the uppermost mantle or crust. Once formed, such an enriched fraction should resist recycling into the mantle and collect at or near the Earth's surface. One possibility is that it collects chiefly in a zone of partial melting, analogous to the present low-velocity zone at the base of the lithosphere.

Condie, K. C.↗
NASA NTRS1993

Mass optical storage-tape (MOST)

In today's large mainframe and supercomputer environment there exists a continuous demand for increased performance in digital storage systems. The user need for near-line storage capacity is currently doubling every four years. In addition to higher capacity, a desire exists for higher data transfer rates, and longer term database archivability, at lower, and lower cost. Each component of this quartet of demands appears to be insatiable. Magnetic tape technology presently dominates the digital mass storage markets, but the continuous growth of requirements is drawing attention to the limitations of the technology as an archival mass storage medium. The lowest cost option currently available for long term data storage is to use magnetic tape, although it is not well suited to meeting the need for many tens of years of reliable storage. Today, the majority of magnetic tape mass storage systems are based on the IBM 3480/3490 (or compatible) tape drives. These drives offer only moderate transfer rates and relatively small increments of storage, both of which create a logistics problem due to the large numbers of cartridges necessary in a typical system and the time taken to transfer data. Both higher cartridge capacity and data transfer rates are available in some helical scan magnetic tape systems; however, these command a substantially higher price, exacerbating the cost problem, and are not compatible with most installed systems or tape databases.

Oakley, William S.↗
NASA NTRSDate not supplied

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↗
NASA NTRS2016

Passive Water Assurance Delivery System

This report provides an analysis and evaluation of proposed design improvements to the internal water delivery system of NASA’s passive vegetable growing system. The VEGGIE system is designed to provide fresh vegetables and psychological benefits for astronauts aboard the International Space Station. Preliminary testing conducted by NASA for the VEGGIE system revealed flaws in the water delivery system. In these tests, the interface between the plants and the water reservoir failed to provide passive water delivery through the system both in microgravity experiments and experiments conducted on Earth. Our team’s goal was to fix this interface such that water can be passively delivered from the water reservoir to the plant rooting pillows to grow vegetative crops from seed to harvest. The system requirements outlined by NASA include: minimal total mass, on-demand passive water delivery, same dimensions as existing fixtures, minimal pressure on system to prevent leaking, zero mold growth, minimal swelling or clogging for non-flammable capillary materials, pressure stabilization between the water reservoir and plant pillow bags, even dispersal of water during initial priming, minimal bubble obstruction of capillary interface, maximum gas availability to plant roots, growth in a mixed artificial media (50:50 Arcillite:Fafard #2), and to avoid overwatering and drought conditions for plants. The major proposed design improvements are to use a single-interface capillary cord design to directly connect the water reservoir to the plant-rooting pillows, and to alter the water reservoir to model a propellant management device (PMD) in order to ensure consistent and long term watering for the VEGGIE system. The plant rooting pillow required minimal changes outside of replacing the capillary mat on the bottom of the pillow with O-ring insertion points the single-interface capillary system. - Research was conducted to determine which materials are able to uptake water through capillary action to grow Outredgeous Lettuce plants from seed to harvest. The primary requirements to be met by the team's design and evaluation of the capillary interface were: continuous passive watering for 90 days using non-flammable capillary materials and a peak water delivery rate of 30 mL/hr./0.15 m 2 . The results of the team's experimentation showed that the capillary material Nomex displayed the highest capillary water delivery potential with a maximum flow rate of 3.6 mL/hr. The Nomex capillary systems were the only capillary material to consistently grow Outredgeous Lettuce plants from seed to harvest, and displayed the highest average flow rate for multiple experiment sets. The Nomex material was previously incorporated into the VEGGIE system using a matted version of the capillary material, though the team recommends using a cord configuration in the single-interface capillary system for greater system stability. Nomex has proven to be a promising material, as it has passed both health and fire standards for use aboard the International Space Station. PMDs are made of materials that utilize surface tension and adhesive forces to overcome adverse accelerations to improve stability and ensure fluid delivery. PMDs are typically used in fuel tanks to ensure fuel delivery. The team recommends using a sponge PMD in order to mitigate bubble obstruction, decrease system weight, and ensure reliable water delivery to the capillary interface. The PMD water reservoir requires a rigid water reservoir and a vent tube for pressure stabilization. Since PMD’s cannot be tested in 1-G (Earth conditions), further theoretical modeling and testing is required for the proposed water reservoir design. The intent of this proposed system is to passively water plants in microgravity, though the technology is not limited to microgravity applications. The testing at The Ohio State University has proven that the design is highly effective on Earth, demonstrating that it could serve as a simple water delivery system in home and office applications. This would make vegetative crops more accessible in all indoor applications, thereby improving indoor air quality and occupant comfort. Additionally, this technology has great potential to be utilized in greenhouse plant production, cutting back on more sophisticated watering system energy and time requirements.

Alexandria Jensen↗
NASA NTRS1975

Space processing of crystals for opto-electronic devices: The case for solution growth

The results obtained during a six month program aimed at determining the viability of space processing in the 1980's of dielectric-elastic-magnetic single crystals were described. The results of this program included: identification of some important emerging technologies dependent on dielectric-elastic-magnetic crystals, identification of the impact of intrinsic properties and defects in the single crystals on system performance, determination of a sensible common basis for the many crystals of this class, and identification of the benefits of micro-gravity and some initial experimental evidence that these benefits can be realized in space. It is concluded that advanced computers and optical communications are at a development stage for high demand of dielectric-elastic-magnetic single crystals in the mid-1980's. Their high unit cost and promise for significantly increased perfection by growth in space justified pursuit of space processing.

Hayden, S. C.↗
NASA NTRS1976

The challenge for improved air cargo capability

Requirements for a strategic air cargo capability are considered. Practical national resource investment considerations dictate that future military strategic airlift planners regard civil capabilities as an integral part of the solution. Attention is given to the military needs for airlift, the civil-military airlift commonality, the present air cargo business, growth projections for civil air cargo, future air cargo business, the introduction date for a dedicated airfreighter, and the demands for transport aircraft.

Vaughan, J.↗
NASA NTRS1996

Status of multijunction solar cells

This paper describes Applied Solar's present activity on Multijunction (MJ) space cells. We have worked on a variety of MJ cells, both monolithic and mechanically stacked. In recent years, most effort has been directed to GaInP2/GaAs monolithic cells, grown on Ge substrates, and the status of this cell design will be reviewed here. MJ cells are in demand to provide satellite power because of the acceptance of the overwhelming importance of high efficiency to reduce the area, weight and cost of space PV power systems. The need for high efficiencies has already accelerated the production of GaAs/Ge cells, with efficiencies 18.5-19%. When users realized that MJ cells could provide higher efficiencies (from 22% to 26%) with only fractional increase in costs, the demand for production MJ cells increased rapidly. The main purpose of the work described is to transfer the MOCVD growth technology of MJ high efficiency cells to a production environment, providing all the space requirements of users.

Yeh, Y. C. M.↗
NASA NTRS1997

Laser-Induced Incandescence in Microgravity

Knowledge of soot concentration is important due to its presence and impact upon a wide range of combustion processes ranging from diffusion to premixed flames, laminar to turbulent processes and homogeneous to heterogeneous combustion. Measurement of soot volume fraction (f(sub v)) is essential to discerning its formation and growth. The presence of soot also affects other physical and chemical properties of combustion thereby affecting studies not directly concerned with either its formation or growth, such as radiative heat transfer, CO oxidation and fuel vaporization or pyrolysis rates. Microgravity offers unique opportunities for studying both soot growth and the effect of soot radiation upon flame structure and spread. Spatial scales and residence time scales are greatly extended in 0-g facilitating soot growth studies. With the varied geometries, short duration microgravity test times and time-varying processes there is a demand for measurement of f(sub v) with high spatial and temporal resolution. Laser-induced incandescence (LII) has advanced f(sub v) measurements in many 1-g combustion processes. To create laser-induced incandescence, a pulsed high intensity laser heats soot to incandescence temperatures. Using appropriate spectral and temporal detection conditions, the resulting incandescence can be selectively detected apart from the non-laser-heated soot and flame gases. Theoretical modelling and experiments have shown that the resulting incandescence is representative of f(sub v). Using an intensified array camera and a laser sheet for excitation, one- and two-dimensionally resolved LII images of f(sub v) have been obtained in 1-g. LII has been characterized and developed at NASA-Lewis for soot volume fraction determination in a wide range of 1-g combustion applications. Broadly grouped, the characterization work has included studies of excitation intensity, excitation wavelength and the optimum temporal and spectral detection conditions to enable an accurate representation of soot volume fraction by LII. Tests for special requirements imposed by different combustion processes have been performed in laminar and turbulent diffusion flames, rich sooting premixed flames, single droplet combustion, and other heterogeneous combustion. These studies demonstrated LII's high sensitivity, temporal and spatial capabilities and its geometric versatility. In contrast to the advantages offered to combustion studies by a microgravity environment, advanced diagnostics, specifically those requiring pulsed laser diagnostics have been limited due to the size, weight and power limitations in a low-gravity environment. Reported here are the first demonstrations of LII performed in a microgravity environment. Examples are shown for laminar and turbulent gas-jet diffusion flames in 0-g.

VanderWal, Randy L.↗
NASA NTRS1992

History of on-orbit satellite fragmentations

Since the first serious satellite fragmentation occurred in Jun. 1961, and instantaneously increased the total Earth satellite population by more than 400 percent, the issue of space operations within the finite region of space around the Earth has been the subject of increasing interest and concern. The prolific satellite fragmentations of the 1970's and the marked increase in the number of fragmentations in the 1980's served to widen international research into the characteristics and consequences of such events. Plans for large, manned space stations in the next decade and beyond demand a better understanding of the hazards of the dynamic Earth satellite population. The contribution of satellite fragmentations to the growth of the Earth satellite population is complex and varied. The majority of detectable fragmentation debris have already fallen out of orbit, and the effects of 40 percent of all fragmentations have completely disappeared. In this volume, satellite fragmentations are categorized by their assessed nature and to a lesser degree by their effect on the near-Earth space environment. A satellite breakup is the usually destructive disassociation of an orbital payload, rocket body, or structure, often with a wide range of ejecta velocities. A satellite breakup may be accidental or the result of intentional actions, e.g., due to a propulsion system malfunction or a space weapons test, respectively. An anomalous event is the unplanned separation, usually at low velocity, of one or more detectable objects from a satellite which remains essentially intact. Anomalous events can be caused by material deterioration of items such as thermal blankets, protective shields, or solar panels. As a general rule, a satellite breakup will produce considerably more debris, both trackable and non-trackable, than an anomalous event. From one perspective, satellite breakups may be viewed as a measure of the effects of man's activity on the environment, while anomalous events may be a measure of the environment on man-made objects.

Nauer, David J.↗
NASA NTRS1998

Elevated Temperature Crack Growth Behavior in HSCT Structural Materials

Structures in super-sonic aircraft are subjected to conditions of high temperature and cyclic and sustained loading for extended periods of time. The durability of structures fabricated from aluminum and certain titanium alloys in such demanding conditions is of primary concern to the designers and manufacturers of futuristic transport aircraft. Accordingly, the major goal of this project was to evaluate the performance and durability of high temperature aluminum and titanium alloys for use in high speed civil transport (HSCT) structures. Additional goals were to develop time-dependent fracture mechanics methodology and test methods for characterizing and predicting elevated temperature crack growth behavior in creep-brittle materials such as ones being considered for use in HSCT structures and to explore accelerated methods of simulating microstructural degradation during service and measuring degraded properties in these materials.

Saxena, Ashok↗