6,902 research outputs found

    Third Conference on Artificial Intelligence for Space Applications, part 2

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    Topics relative to the application of artificial intelligence to space operations are discussed. New technologies for space station automation, design data capture, computer vision, neural nets, automatic programming, and real time applications are discussed

    Practical reliability. Volume 3 - Testing

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    Application of testing to hardware program

    A manual for pyrotechnic design, development and qualification

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    Although pyrotechnic devices have been singularly responsible for the success of many of the critical mechanical functions in aerospace programs for over 30 years, ground and in-flight failures continue to occur. Subsequent investigations reveal that little or no quantitative information is available on measuring the effects on performance of system variables or on determining functional margins. Pyrotechnics are considered to be readily available and, therefore, can be managed by any subsystem in which they are applied, such as structure, propulsion, electric power, or life support. The primary purpose of this manual is to alter the concept that the use of pyrotechnics is an art and refute 'justifications' that applications do not need to be understood by providing information on pyrotechnic design, development, and qualification on an engineering basis. Included are approaches to demonstrate functional reliability with less than 10 units, how to manage pyrotechnic-unique requirements, and methods to assure that the system is properly assembled and will perform the required tasks

    Spray automated balancing of rotors: Methods and materials

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    The work described consists of two parts. In the first part, a survey is performed to assess the state of the art in rotor balancing technology as it applies to Army gas turbine engines and associated power transmission hardware. The second part evaluates thermal spray processes for balancing weight addition in an automated balancing procedure. The industry survey reveals that: (1) computerized balancing equipment is valuable to reduce errors, improve balance quality, and provide documentation; (2) slow-speed balancing is used exclusively, with no forseeable need for production high-speed balancing; (3) automated procedures are desired; and (4) thermal spray balancing is viewed with cautious optimism whereas laser balancing is viewed with concern for flight propulsion hardware. The FARE method (Fuel/Air Repetitive Explosion) was selected for experimental evaluation of bond strength and fatigue strength. Material combinations tested were tungsten carbide on stainless steel (17-4), Inconel 718 on Inconel 718, and Triballoy 800 on Inconel 718. Bond strengths were entirely adequate for use in balancing. Material combinations have been identified for use in hot and cold sections of an engine, with fatigue strengths equivalent to those for hand-ground materials

    Advanced flight control system study

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    The architecture, requirements, and system elements of an ultrareliable, advanced flight control system are described. The basic criteria are functional reliability of 10 to the minus 10 power/hour of flight and only 6 month scheduled maintenance. A distributed system architecture is described, including a multiplexed communication system, reliable bus controller, the use of skewed sensor arrays, and actuator interfaces. Test bed and flight evaluation program are proposed

    Reliability of ceramics for heat engine applications

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    The advantages and disadvantages associated with the use of monolithic ceramics in heat engines are discussed. The principle gaps in the state of understanding of ceramic material, failure origins, nondestructive tests as well as life prediction are included

    Advanced information processing system: The Army fault tolerant architecture conceptual study. Volume 1: Army fault tolerant architecture overview

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    Digital computing systems needed for Army programs such as the Computer-Aided Low Altitude Helicopter Flight Program and the Armored Systems Modernization (ASM) vehicles may be characterized by high computational throughput and input/output bandwidth, hard real-time response, high reliability and availability, and maintainability, testability, and producibility requirements. In addition, such a system should be affordable to produce, procure, maintain, and upgrade. To address these needs, the Army Fault Tolerant Architecture (AFTA) is being designed and constructed under a three-year program comprised of a conceptual study, detailed design and fabrication, and demonstration and validation phases. Described here are the results of the conceptual study phase of the AFTA development. Given here is an introduction to the AFTA program, its objectives, and key elements of its technical approach. A format is designed for representing mission requirements in a manner suitable for first order AFTA sizing and analysis, followed by a discussion of the current state of mission requirements acquisition for the targeted Army missions. An overview is given of AFTA's architectural theory of operation

    Flight Technology Improvement

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    Shortcomings in spaceborne instrumentation technology are analyzed and recommendations are given for corrections and technology development. The technologies discussed are optical radiometric instruments and calibration, attitude control and determination, and electromechanical and power subsystems

    Preliminary design of a 100 kW turbine generator

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    The National Science Foundation and the Lewis Research Center have engaged jointly in a Wind Energy Program which includes the design and erection of a 100 kW wind turbine generator. The machine consists primarily of a rotor turbine, transmission, shaft, alternator, and tower. The rotor, measuring 125 feet in diameter and consisting of two variable pitch blades operates at 40 rpm and generates 100 kW of electrical power at 18 mph wind velocity. The entire assembly is placed on top of a tower 100 feet above ground level

    Methodology for Assessing Reliability Growth Using Multiple Information Sources

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    The research presented here examines the assessment of the reliability of a system or product utilizing multiple data sources available throughout the different stages of its development. The assessment of the reliability as it changes throughout the development of a system is traditionally referred to as reliability growth, which refers to the discovery and mitigation of failure modes within the system, thereby improving the underlying reliability. Traditional models for assessing reliability growth work with test data from individual test events to assess the system reliability at the current stage of development. These models track or project the reliability of the system as it matures subject to the specific assumptions of the models. The contributions of this research are as follows. A new Bayesian reliability growth assessment technique is introduced for continuous-use systems under general corrective action strategies. The technique differs from those currently in the literature due to the allowance for arbitrary times for corrective actions. It also provides a probabilistic treatment of the various parameters within the model, accounting for the uncertainty present in the assessment. The Bayesian reliability growth assessment model is then extended to include results from operational testing. The approach considers the posterior distribution from the reliability growth assessment of the prior for the operational reliability assessment. The developmental and operational testing environments are not a priori assumed to be equivalent, and the change in environments is accounted for in a probabilistic manner within the model. A Bayesian reliability growth planning model is also presented that takes advantage of the reduced uncertainty in the combined operational assessment. The approach allows for reductions in the amount of demonstration testing necessary for a given level of uncertainty in the assessment, and it can also be used to reduce high design goals that often result from traditional operating characteristic curve applications. The final part of this research involves combining various sources of reliability information to obtain prior distributions on the system reliability. The approach presents a general framework for utilizing information such as component/subsystem testing, historical component reliability data, and physics-based modeling of specific component failure mechanisms
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