NASA Scientific and Technical Aerospace Reports

otor and blades, were found to be inaccurate and, more importantly, insufficient to facilitate controller design. Some
assumptions made to facilitate the previous results were not valid, and thus improvements are presented here to better match
the physical reality. As will be shown, the improved temperature sub- models, match a commercially validated model and are
sufficiently simplified to aid in controller design.
Author
Temperature Profiles; Dynamic Models; Turbines; Engine Parts
20040071041 NASA Marshall Space Flight Center, Huntsville, AL, USA
Friction Stir Welding of GR-Cop 84 for Combustion Chamber Liners
Russell, Carolyn K.; Carter, Robert; Ellis, David L.; Goudy, Richard; 2004; 9 pp.; In English; 45th AIAA/ASME/ASCE/
AHS/ASC Structures, Structural Dynamics and Materials Conference, 19-22 Apr. 2004, Palm Springs, CA, USA; No
Copyright; Avail: CASI; A02, Hardcopy
GRCop-84 is a copper-chromium-niobium alloy developed by the Glenn Research Center for liquid rocket engine
combustion chamber liners. GRCop-84 exhibits superior properties over conventional copper-base alloys in a liquid
hydrogen-oxygen operating environment. The Next Generation Launch Technology program has funded a program to
demonstrate scale-up production capabilities of GR-Cop 84 to levels suitable for main combustion chamber production for the
prototype rocket engine. This paper describes a novel method of manufacturing the main combustion chamber liner. The
process consists of several steps: extrude the GR-Cop 84 powder into billets, roll the billets into plates, bump form the plates
into cylinder halves and friction stir weld the halves into a cylinder. The cylinder is then metal spun formed to near net liner
dimensions followed by finish machining to the final configuration. This paper describes the friction stir weld process
development including tooling and non-destructive inspection techniques, culminating in the successful production of a liner
preform completed through spin forming.
Author
Chromium Alloys; Preforms; Powder (Particles); Niobium Alloys; Manufacturing; Friction Stir Welding
20040073438 General Electric Co., Niskayuna, NY, USA
Disk Crack Detection for Seeded Fault Engine Test
Luo, Huageng; Rodriguez, Hector; Hallman, Darren; Corbly, Dennis; Lewicki, David G., Technical Monitor; June 2004;
54 pp.; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): NAS3-01135; WBS-22-728-30-03
Report No.(s): NASA/CR-2004-213069; E-14545; No Copyright; Avail: CASI; A04, Hardcopy
Work was performed to develop and demonstrate vibration diagnostic techniques for the on-line detection of engine rotor
disk cracks and other anomalies through a real engine test. An existing single-degree-of-freedom non-resonance-based
vibration algorithm was extended to a multi-degree-of-freedom model. In addition, a resonance-based algorithm was also
proposed for the case of one or more resonances. The algorithms were integrated into a diagnostic system using state-of-theart
commercial analysis equipment. The system required only non-rotating vibration signals, such as accelerometers and
proximity probes, and the rotor shaft 1/rev signal to conduct the health monitoring. Before the engine test, the integrated
system was tested in the laboratory by using a small rotor with controlled mass unbalances. The laboratory tests verified the
system integration and both the non-resonance and the resonance-based algorithm implementations. In the engine test, the
system concluded that after two weeks of cycling, the seeded fan disk flaw did not propagate to a large enough size to be
detected by changes in the synchronous vibration. The unbalance induced by mass shifting during the start up and coast down
was still the dominant response in the synchronous vibration.
Author
Cracks; Detection; Vibration; Diagnosis; Engine Tests; Rotons
20040073465 National Inst. of Aerospace Research, Hampton, VA, USA, NASA Langley Research Center, Hampton, VA,
USA
Stress Distribution During Deformation of Polycrystalline Aluminum by Molecular-Dynamics and Finite-Element
Modeling
Yamakov, V.; Saether, E.; Phillips, D.; Glaessgen, E. H.; March 25, 2004; 9 pp.; In English; 45th AIAA/ASME/ASCE/AHS/
ASC Structures, Structural Dynamics, and Materials Conference, 19-22 Apr. 2004, Palm Springs, CA, USA
Contract(s)/Grant(s): NAS1-00135; NCC1-02043; 706-63-51
Report No.(s): AIAA Paper 2004-1700; No Copyright; Avail: CASI; A02, Hardcopy
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