1,518 research outputs found

    Life prediction of materials exposed to monotonic and cyclic loading: A new technology survey

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    Reviewed and evaluated technical abstracts for about 100 significant documents are reported relating primarily to life prediction for structural materials exposed to monotonic and cyclic loading, particularly in elevated temperature environments. The abstracts in the report are mostly for publications in the period April 1962 through April 1974. The purpose of this report is to provide, in quick reference form, a dependable source for current informatio

    Life prediction of materials exposed to monotonic and cyclic loading: Bibliography

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    This bibliography is comprised of approximately 1200 reference citations related to the mechanics of failure in aerospace structures. Most of the references are for information on life prediction for materials exposed to monotonic and cyclic loading in elevated temperature environments such as that in the hot end of a gas turbine engine. Additional citations listed are for documents on the thermal and mechanical effects on solar cells in the cryogenic vacuum environment; radiation effects on high temperature mechanical properties; and high cycle fatigue technology as applicable to gas turbine engine bearings. The bibliography represents a search of the literature published in the period April 1962 through April 1974 and is largely limited to documents published in the United States. It is a companion volume to NASA CR-134750, Life Prediction of Materials Exposed to Monotonic and cyclic Loading - A Technology Survey

    A review of physics-based models in prognostics: application to gears and bearings of rotating machinery

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    Health condition monitoring for rotating machinery has been developed for many years due to its potential to reduce the cost of the maintenance operations and increase availability. Covering aspects include sensors, signal processing, health assessment and decision-making. This article focuses on prognostics based on physics-based models. While the majority of the research in health condition monitoring focuses on data-driven techniques, physics-based techniques are particularly important if accuracy is a critical factor and testing is restricted. Moreover, the benefits of both approaches can be combined when data-driven and physics-based techniques are integrated. This article reviews the concept of physics-based models for prognostics. An overview of common failure modes of rotating machinery is provided along with the most relevant degradation mechanisms. The models available to represent these degradation mechanisms and their application for prognostics are discussed. Models that have not been applied to health condition monitoring, for example, wear due to metal–metal contact in hydrodynamic bearings, are also included due to its potential for health condition monitoring. The main contribution of this article is the identification of potential physics-based models for prognostics in rotating machinery

    Aeronautical engineering: A continuing bibliography with indexes, supplement 100

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    This bibliography lists 295 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System in August 1978

    Aeronautical Engineering: A special bibliography, supplement 60

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    This bibliography lists 284 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1975

    NDE: An effective approach to improved reliability and safety. A technology survey

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    Technical abstracts are presented for about 100 significant documents relating to nondestructive testing of aircraft structures or related structural testing and the reliability of the more commonly used evaluation methods. Particular attention is directed toward acoustic emission; liquid penetrant; magnetic particle; ultrasonics; eddy current; and radiography. The introduction of the report includes an overview of the state-of-the-art represented in the documents that have been abstracted

    Aeronautical engineering: A special bibliography with indexes, supplement 80

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    This bibliography lists 277 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1977

    Aeronautical engineering: A special bibliography with indexes, supplement 82, April 1977

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    This bibliography lists 311 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1977

    Aeronautical engineering: A continuing bibliography, supplement 122

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    This bibliography lists 303 reports, articles, and other documents introduced into the NASA scientific and technical information system in April 1980

    Aeronautical Engineering: A special bibliography with indexes, supplement 67, February 1976

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    This bibliography lists 341 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1976
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