Test apparatus is designed for determining tensile strength, modulus of elasticity, elongation, and thermal coefficient of contraction or expansion of uniformly shaped plastics, adhesives, and foam materials over temperature range of 700 to 90 K (800 to -300). Tests may be used in design quality control, and in evaluation of new adhesives and plastic materials

Helf, J. C.

Hill, W. L.

Pontius, H. L.

English

NASA Technical Reports Server

Environmental 
Chamber Specimen 
Attachment Clevis Rods 
And Pins Should Be 
Fabricated Of A Material 
With Thermal Expansion 
Characteristics Of Invar
Magnet Bonded

To Phenolic
With Epoxy
Adhesive 
December 1972
	 B72-10679 
ff NASA TECH BRIEF Marshall Space Flight 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. 
A Monostrain Test Apparatus 
Phenolic 
Cylinder
Dial
Indicator
Rod 
Phenolic Tube
Dial Indicator 
(Free Movement 
0.001-Inch, 0.025-mm, 
Increments) 
A monostrain testing apparatus was designed for 
determining the tensile strength, modulus of elasticity, 
elongation, and the thermal coefficient of contraction 
or expansion of uniformly shaped plastics, adhesives, 
and foam materials over a temperature range of 700 to 
90K (800 to —3000F). Test specimens are prepared by 
several methods. For example, sheets of paste adhesive 
systems and primer materials are cast on a flat surface 
which is covered with an appropriate release material.
The desired thickness of the sheet may be controlled 
with aluminum strips acting as dikes for the casting. 
Sheet adhesives and film plastics are cured on a flit 
sheet covered with an appropriate release material. Test 
specimens of foam are prepared by machining from 
sections of sprayed foam. All the test specimens, whether 
cut or machined to configuration required for the test, 
must be uniform in cross-sectional area within ten per-
cent for specimens to 0.25 mm (0.010 inch) thick and 
(continued overleaf) 
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=19720000678 2020-03-17T03:42:27+00:00Z
five percent (or 0.025 mm, 0.001 inch, whichever is 
greater) for thicknesses to 1.52 mm (0.060 inch). 
For the thermal contraction or expansion test (see 
figure), the specimen is installed in the environmental 
chamber and suspended from the upper clevis. A pheno-
lic cylinder with a clevis attached is suspended freely 
from the lower end of the test specimen. A magnet 
bonded to the bottom of the cylinder point contacts 
the free moving arm of a dial indicator. The indicator is 
located within and attached to a phenolic tube that 
rests on the lower platen of the test machine. At stabili-
zation of test temperature, the indicator will indicate 
the contraction or expansion of the test specimen. The 
free weight of the apparatus attached to the bottom of 
the specimen is such that room temperature elongation 
(creep) will not exceed 0.01% per unit length per hour. 
For thermal expansion tests, this suspended weight 
should not cause significant creep at the maximum 
temperature of the test. 
In tensile testing, the specimen is assembled in the 
loading devises within the environmental chamber after 
the test machine is balanced at zero load. Specimen 
alignment in the vertical axis must be accomplished prior 
to loading. The deflector, or strain measuring instru-
ment, is installed in a position that will permit vertical 
movement at the center of the loading platen to be 
recorded. During heating or cooling of the test specimen, 
the test assembly is operated to position the movable 
platen and allow for expansion or contraction of the 
specimen. The tensile test is initiated after the desired
test temperature has been stabilized within the specimen 
for a period of ten minutes. The rate of loading should 
be compatible with the material being tested in that 
creep will be negligible and failure should occur in two 
to five minutes. Tensile testing at temperatures in 
excess of 535K (500°F) requires serrated clamping 
type plates for gripping the ends of the specimens. 
Machining the hole for pin loading is omitted for 
specimens to be loaded in this manner. 
Notes: 
1. The mechanical and physical properties of materials 
determined by these tests may be used in design, 
quality control, and in the evaluation of new adhesives 
and plastic materials. 
2. Requests for further information may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Code A&PS-TU 
Marshall Space Flight Center, Alabama 35812 
Reference: B72-10679 
Patent status: 
NASA has decided not to apply for a patent. 
Source: W. L. Hill, H. L. Pontius and
.
 J. C. Helf of
North American Rockwell Corp. 
under contract to

Marshall Space Flight Center

(MFS-24221)
V 
B72-10679	 Category 04, 06


A monostrain test apparatus

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