Anti-buckling assembly prevents buckling of sheet metal fatigue specimen when axial compressive load is applied. It provides for cyclic heating and cooling of specimen during testing. Assembly permits tests at two locations on specimen. Device has ports for visual, optical, or photographic monitoring of fatigue crack propagation in test specimen

Eichenbrenner, F. E.

Imig, L. A.

English

NASA Technical Reports Server

See Note 
1p",
Intake 
Manifold
See Note
['1 
R' Manifold 
Slotted 
Guides
February 1973	 B73-10047 
NASA TECH BRIEF 
Langley Research Center 
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. 
Fatigue Testing Device 
.
An anti-buckling assembly has been developed which 
prevents buckling of a sheet metal fatigue specimen 
when axial compressive load is applied; it has provisions 
for cyclic heating and cooling of the specimen during 
testing; it permits simultaneous tests at two locations 
on the specimen; and has ports for visual, optical, or 
photographic monitoring of fatigue crack propagation 
in the test specimen. 
The main components of the assembly(see illustration) 
are the slotted guides. The slotted guides are used in 
pairs and are placed over the test specimen with the 
slotted sides of the guides facing the specimen as it is 
mounted in the fatigue machine. Shims are inserted 
between the guides in such a manner thatj neither the 
shims nor guides interfere with the test specimen. With 
the guides in this position they assure that the specimen 
does not buckle when compressive loads are applied. 
The guides contain passages for the movement of air 
to cool the specimen, a mounting for a heat source to 
heat the specimen, and ports for viewing fatigue cracks.
Reflectors, upon which are mounted quartz-envelope 
heating lamps, reflect radiant energy to the test specimen 
through the viewing ports in the guides. The viewing 
ports in the guides are covered with a heat resistant 
window which prevents air from circulating and disrupt-
ing the temperature uniformity of the specimen. 
The test specimen is cooled by pressurized air 
through one end of the intake manifold and the channels 
in the guides. A special fitting assures that the air supply 
to each of the test areas is equal. The heated air is 
expelled through another port in the intake manifold 
and through the exhaust manifold. 
Similar assemblies may be designed to accommodate 
specimens with other than two test sections and of 
different shapes. Cooling at different rates may be 
achieved by using media other than compressed air. 
Heating rates are dependent on thc type of controller 
used [in this device temperature may be cycled from 
room temperature to 588 K (6000 F) to room temper-
ature in less than one minute]. 
Slotted 
Reflector	 Guide 
See Note 
Window
(Heat Resistant)
Window 
o 
O^
Th- 
>J+ iI'! J ir 0	 Reflector 
Insulation	 Insulation 
Cover	 Cover 
Note: 
Quartz Lamp Mounting And Insulating Pieces. 
(continued overleaf) 
Thisdocumentwas 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=19730000047 2020-03-17T06:41:17+00:00Z
Note 
No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Langley Research Center 
Mail Stop 139 A 
Hampton, Virginia 23365 
Reference: B73-10047
Patent status,: 
Inquiries concerning rights for the commercial use 
of this invention should be addressed to: 
Patent Counsel 
Langley Research Center 
Code 456 
Hampton,Virginia 23365 
Source: F. E. Eichenbrenner and L. A. Imig

Langley Research Center

(LAR-1 0426)
. 
B73-10047	 Category 04, 07


Fatigue testing device

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