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Silicon Nitride Creep Under Various Specimen-Loading ConfigurationsExtensive creep testing of a hot-pressed silicon nitride (NC 132) was performed at 1300 C in air using five different specimen-loading configurations: (1) pure tension, (2) pure compression, (3) four-point uniaxial flexure, (4) ball-on-ring biaxial flexure, and (5) ring-on-ring biaxial flexure. This paper reports experimental results as well as test techniques developed in this work. Nominal creep strain and its rate for a given nominal applied stress were greatest in tension, least in compression, and intermediate in uniaxial and biaxial flexure. Except for the case of compression loading, nominal creep strain generally decreased with time, resulting in a less-defined steady-state condition. Of the four creep formulations-power-law, hyperbolic sine, step, and redistribution--the conventional power-law formulation still provides the most convenient and reasonable estimation of the creep parameters of the NC 132 material. The data base to be obtained will be used to validate the NASA Glenn-developed design code CARES/Creep (ceramics analysis and reliability evaluation of structures and creep).
Document ID
20000120387
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Choi, Sung R.
(Ohio Aerospace Inst. Brook Park, OH United States)
Holland, Frederic A.
(NASA Glenn Research Center Cleveland, OH United States)
Date Acquired
September 7, 2013
Publication Date
November 1, 2000
Subject Category
Structural Mechanics
Report/Patent Number
NAS 1.15:210026
E-12223
NASA/TM-2000-210026
Funding Number(s)
PROJECT: RTOP 910-30-11
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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