Split nut with internal taper to hold specially formed specimen composed of filaments of refractory material provides means for holding at high temperature and under tension so that performance evaluations may be made

Coulbert, C. D.

English

NASA Technical Reports Server

Spread Filaments 
to Form Head 
Pyrolytically Bonded 
High Tensile 
Filament 
Rod
1972	 1.	 B72-10028 
NASA TECH BRIEF 
Ames Research Center 	
-4 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield; Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Specimen for High-Temperature Tensile Tests 
The problem: 
To hold a specimen composed of filaments or yams 
of refractory material at high temperature and under 
tension so that its performance may be evaluated. 
The solution: 
A split nut with an internal taper and a specimen 
fabricated with a specially formed end to fit within 
the assembled nut. 
How it's done: 
The tensile member consists of a bundle of high-
strength filaments, such as carbon yarn, which has 
been impregnated and bonded pyrolytically to form 
a solid, high-strength part. In composite structures 
of this type, the temperature limits are set by the 
strength vs. temperature properties of the filament 
and the bond. With pure carbon fibers and pyrolytic 
graphite bonding, the strength of such members 
should be retained at temperatures as high as 
2200°C (4000°F).
As indicated in the diagram, the tension member 
contains filaments or yarns neatly aligned and closely 
spaced in the rod-like central portion, but the fila-
ments are spread at the ends before bonding to form 
the head which will support the member during the 
test. This technique of forming the ends allows trans-
fer of load from the rod by shear across the filaments 
rather than shear parallel to the filaments. 
The test specimen may be of any cross section 
(square, round, hollow, irregular, etc.) and of a 
length determined solely by the available furnaces 
and testing machines or devices. 
The split nut shown in the diagram is formed so 
that its internal taper matches the taper of the formed 
head on the tensile specimen. Its external thread is 
dimensioned to fit the chucks of the testing machine. 
Note: 
No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: B72-10028 
Patent status: 
No patent action is contemplated by NASA. 
Source: C. D. Coulbert of 
The Marquardt Company
under contract to
Ames Research Center 
(ARC-10531) 
Category 04 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States 	 will be free from privately owned rights. 
https://ntrs.nasa.gov/search.jsp?R=19720000028 2020-03-17T03:23:51+00:00Z


Specimen for high-temperature tensile tests

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