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Space Shuttle Main Engine High Pressure Fuel Turbopump Turbine Blade CrackingThe analytical results from two-dimensional (2D) and three-dimensional (3D) finite element model investigations into the cracking of Space Shuttle Main Engine (SSME) High Pressure Fuel Turbopump (HPFTP) first- and second-stage turbine blades are presented. Specifically, the initiation causes for transverse cracks on the pressure side of the firststage blade fir tree lobes and face/corner cracks on the downstream fir tree face of the second-state blade are evaluated. Because the blade material, MAR-M-246 Hf (DS), is highly susceptible to hydrogen embrittlement in the -100 F to 400 F thermal environment, a steady-state condition (full power level = 109 percent) rather than a start-up or shut-down transient was considered to be the most likely candidate for generating a high-strain state in the fir tree areas. Results of the analyses yielded strain levels on both first- and second-stage blade fir tree regions that are of a magnitude to cause hydrogen assisted low cycle fatigue cracking. Also evident from the analysis is that a positive margin against fir tree cracking exists for the planned design modifications, which include shot peening for both first- and second-stage blade fir tree areas.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Lee, Henry
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
September 5, 2013
Publication Date
May 1, 1988
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
NAS 1.15:100327
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.
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