Structural Uses for Ductile Ordered Alloys (1984) / Chapter Skim
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'POTENTIAL DEPARTMENT OF DEFENSE APPLICATIONS'
'POTENTIAL DEPARTMENT OF DEFENSE APPLICATIONS'
Pages 49-68
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From page 49... ...
These include specifications from which approval for deviation would be required, sole source conditions to which many contractors might justifiably object, production schedules so tight that time for usage validation is not available before final commitment to full scale production is required, and poor part performance, which encourages conservatism on the contractors part. Component selection for early ductile ordered alloy application should attempt to minimize these factors.
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From page 50... ...
1982) which shows the required structural thicknesses to sustain the various failure limits in an aircraft structure built of two competitive materials.
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51 Q) "8 1 •o 2 cr Strength Crack Propagation Strength Aerodynamic Loads Buckling Buckling Aerodynamic Loads Basic material Hypothetical new material that is stronger and stiffer, but no better in crack propagation resistance FIGURE 12 Potential weight savings considering additional failure modes (based on Ekvall 1982)
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From page 52... ...
Many of those listed in Table 7 have already passed this conceptual stage and, therefore, application windows have apparently been closed. However, high-performance vehicles often experience unacceptable weight increases during prototype development, and component failures also are not uncommon at this stage.
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53 AIRCRAFT ENG1NES T CF ADV DEV PROTOTYPE DEV PRODUCT1ON t t t ft ORIG1NAL DES1GN WE1GHT TEST 1N•SERV1CE ENV1RONMENTAL GROWTH FA1LURES FA1LURES TROUBLES TECH DEMO DEMO ENGINE PROTOTYPE DEV PRODUCT1ON 1 t OR1GINAL TEST DES1GN FA1LURES TECH DEMO MOD DEV PRODUCT1ON EXPER1MENTAL RA1SE PERFORMANCE OR TECH DEMO MOD DEV PRODUCT1ON EXPER1MENTAL 1NCREASE TBO 15 10 T1ME (years) 10 FIGURE 13 New material application windows (Ekvall et al.
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From page 54... ...
For example, government agencies often fund much of the initial screening program through to manufacturing technology demonstrations before the material is incorporated into a product acquired by DOD. In many cases close coordination of all stages aids greatly in providing periodic feedback and program continuity.
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55 10 w z o 1ncorporation ^•^B QUAL1F1CAT1ON'" Engine Test F Rig Test Specifications Processing-Secondary DEVELOPMENT r Design Data Processing•Primary Cost Benefit Study T Laboratory. ' Demonstration I 5 YEARS 10 FIGURE 14 Typical development sequence for a new material being incorporated into a defense system (courtesy of United Technologies, Inc., Pratt and Whitney Aircraft)
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From page 56... ...
Alloys with good high-temperature strength and oxidation resistance and low density would seem especially advantageous in rotating parts in which centrifugal loads may account for about 75 percent of the total loading. Figure 15 illustrates a typical large transport aircraft turbofan engine and Table 8 lists property requirements and failure modes possible for the various components.
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58 s s •• 1 I I I 01 T A 8 js e S £ 1 E E E 0 o Y •H | 9 ; hot-c 2 ti i U "c u j i cd ^ • •j •jj ^ 0 t .o • m en i o § • !
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59 FIGURE 16 Fan assembly of a CF6-80 engine (courtesy of General Electric Company)
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60 FIGURE 17 Compressor rotor of a CF6-6 engine (courtesy of General Electric Company)
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61 FIGURE 18 Combustion chamber of a JT9D engine (courtesy of United Technologies Corporation, Pratt and Whitney Aircraft)
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62 FIGURE 19 High pressure turbine assembly of a CF6-50 engine (courtesy of General Electric Corporation)
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Figures 22 and 23 show typical cross-sections of advanced rocket engine turbomachinery with potential applications being turbine blades, disks, and combustion chamber liners. Other potential aerospace hardware applications for ordered alloys are in advanced metallic thermal protection systems and hot gas ducting for lift augmentation devices.
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64 VANE BLADE FIGURE 20 Turbine blades and vanes of a PW2037 engine (courtesy of United Technologies Corporation, Pratt and Whitney Aircraft)
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65 FIGURE 21 Low pressure turbine assembly of a CF6-6 engine (courtesy of General Electric Corporation)
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66 FIGURE 22 High pressure fuel turbopump (courtesy of Rockwell International, Rocketdyne Division)
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67 • OX1D1ZER PREBURNfR H1GH PRESSURE HYDROGEN TURBOPUMP MA1N COMBUST1ON CHAMBER H1GH PRESSURE OX1D1ZER TURBOPUMP FIGURE 23 Space shuttle main engine powerhead component arrangement (courtesy of Rockwell International, Rocketdyne Division)
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From page 68... ...
1982. Methodology for Evaluating Weight Savings From Basic Material Properties.
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