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The J-2X Fuel Turbopump - Turbine Nozzle Low Cycle Fatigue Acceptance RationaleThe J-2X Fuel Turbopump (FTP) turbine, which drives the pump that feeds hydrogen to the J-2X engine for main combustion, is based on the J-2S design developed in the early 1970 s. Updated materials and manufacturing processes have been incorporated to meet current requirements. This paper addresses an analytical concern that the J-2X Fuel Turbine Nozzle Low Cycle Fatigue (LCF) analysis did not meet safety factor requirements per program structural assessment criteria. High strains in the nozzle airfoil during engine transients were predicted to be caused by thermally induced stresses between the vane hub, vane shroud, and airfoil. The heritage J-2 nozzle was of a similar design and experienced cracks in the same area where analysis predicted cracks in the J-2X design. Redesign options that did not significantly impact the overall turbine configuration were unsuccessful. An approach using component tests and displacement controlled fracture mechanics analysis to evaluate LCF crack initiation and growth rate was developed. The results of this testing and analysis were used to define the level of inspection on development engine test units. The programmatic impact of developing crack initiation/growth rate/arrest data was significant for the J-2X program. Final Design Certification Review acceptance logic will ultimately be developed utilizing this test and analytical data.
Document ID
20120003052
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Hawkins, Lakiesha V.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Duke, Gregory C.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Newman, Wesley R.
(Jacobs Engineering Group, Inc. Huntsville, AL, United States)
Reynolds, David C.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 25, 2013
Publication Date
December 5, 2011
Subject Category
Mechanical Engineering
Report/Patent Number
M11-0688
Meeting Information
Meeting: JANNAF 5th Spacecraft Propulsion Subcommittee Meeting
Location: Huntsville, AL
Country: United States
Start Date: December 5, 2011
End Date: December 9, 2011
Sponsors: Department of the Army, Department of the Air Force, Department of the Navy, NASA Headquarters
Funding Number(s)
CONTRACT_GRANT: NNM06AB13C
Distribution Limits
Public
Copyright
Other

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