Materials Research Agenda for the Automobile and Aircraft Industries (1993) / Chapter Skim
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Materials Research Agenda fr the Civil Aircraft Industry
Materials Research Agenda fr the Civil Aircraft Industry
Pages 49-62
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From page 49... ...
In the few cases where a specific system is favored, it has been identified and discussed. NEED FOR MATERIALS-SYSTEMS APPROACH Innovative materials research and engineering is essential to achieve the high-strength, heat-resistant, lightweight structures required in advanced subsonic and supersonic aircraft.
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From page 50... ...
However, if advanced materials are to be successfully introduced, a more comprehensive materials-system approach must be developed that incorporates materials modeling and processing considerations, and that allows designers to interact even more closely with materials developers to ensure the proper application of new materials. Materials Processing Processing and fabrication play critical roles in the utilization of materials.
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From page 51... ...
One could envision the use of expert systems to help the designer choose appropriate materials and processing techniques for the production of aircraft components. MATERIALS RESEARCH NEEDS FOR AIRCRAFT AIRFRAMES AND ENGINES The materials requirements of the airframe and engine systems of aircraft are sufficiently distinct to permit them to be discussed separately.
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From page 52... ...
Materials Candidates The candidate polymeric composites that can survive the conditions of a Mach 2.4 HSCT airplane for certain structural applications include the carbon-fiber reinforced thermoplastics and thermosets. Cyanate esters and toughened bismaleimides are the
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From page 53... ...
As suggested in Figure 4-2, the takeoff gross weight favors applications of polymeric composites; however, technical and manufacturing uncertainties prevent the elimination of the metal-alloy candidates. Detailed design considerations are required to rank with polymer-matrix composites at
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From page 54... ...
r Jolnlng The ability to achieve lighter-weight and more fatigue-resistant aircraft structures by adhesive bonding in place of riveting was convincingly demonstrated in the Primary Adhesively Bonded Structures Technology program, conducted by McDonnell Douglas for the Air Force (Hart-Smith, 1981~. For successful application, the system for adhesive bonding must be durable in the thermal and chemical environment to which it is exposed.
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From page 55... ...
Therefore, the committee recommends focused research to address the technical problems, such as residual stress, joint efficiency and reliability, fatigue characteristics, and quality assurance, associated with the application of welding to advanced materials for airframes. Interface Science Another associated research opportunity is that of interface science.
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From page 56... ...
The operational temperatures for rear-stage compressor components and first-stage turbine components of the HSCT are also indicated. The materials technology required to improve engine efficiency can be summarized as follows: · Thrust growth in existing engines can be achieved by the use of higher cycle temperatures (T3 and T41)
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From page 57... ...
This tabular summary progresses from advanced subsonic to military demonstrator to the HSCT engines, and from work that is evolutionary in nature and amenable to engineering program approaches through a set of goals that are a radical departure from industry experience. The latter goals require a suitably directed, highly speculative program of materials synthesis and development that might properly be sponsored on an industry-wide basis.
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From page 58... ...
These composites may address certain of the requirements for materials that must operate in the medium-tohigh temperature range, from 600 to 2600~°F. At the lower range of temperature, such materials may be competitive with the fiberreinforced, polyimide-matrix composites, while at the upper range they compete with the capability offered by carbon-carbon composites.
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From page 59... ...
The increasing emphasis on using composites for solutions to the material requirements of advanced engines is shown in Figure 4-4. Advanced materials are viewed by domestic gas-turbine manufacturers as key technology discriminators.
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From page 60... ...
Carbon-fiber reinforced thermoplastics and thermosets, involving the cyanate esters or toughened bismaleimides, are currently favored systems. Compositeresearch opportunities exist in the areas of (l)
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From page 61... ...
Candidate materials are the weldable lithium-containing aluminum alloys and the titanium alloys. The materials research opportunities for aircraft engines are the development of materials with higher-temperature capabilities and thermal efficiency to withstand higher cycle temperatures and reduced cooling flow, superior strength-to-weight characteristics to permit weight reductions, and improved value to reduce overall life-cycle cost.
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