Uniform Tension: the Problem and the Solution

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22 ISSN 0236-3941. Вестник МГТУ им. Н.Э. Баумана. Сер. Машиностроение. 2017. № 5
DOI: 10.18698/0236-3941-2017-5-22-27
UNIFORM TENSION: THE PROBLEM AND THE SOLUTION
A. Eremichev
University Mediterranean Karpasia, Nicosia, N. Cyprus
Abstract Keywords
When we need to plot the failure surface of a material, the
"starting point" is of great importance. It is determined by
results of uniform compression and uniform tension tests.
The former is rather trivial, although greater technical diffi-
culties arise when creating a pressure high enough to make
the material fail. Implementing a uniform tension stress
state, however, and especially simultaneously measuring the
failure stress is a complex scientific and engineering task. We
supply a brief review of articles on the subject. We describe
the sample and the device for implementing triaxial tension
we developed. We provide test results for plexiglas (PMMA)
and carbon-carbon composite material samples
Test samples, uniform tension, uniform
triaxial tension, finite element method,
Drucker’s postulate, plexiglas, carbon-
carbon composite material
Received 24.05.2017
© BMSTU, 2017
To determine the surface of strength [1], of great importance is the "starting point"
which is determined by the results of tests on a uniform all-round compression and a
all-round uniform tension.
The first definition is rather trivial, although associated with greater technical dif-
ficulties when creating the higher pressure at which the material collapses under
compression. The creation of the stress state "all-round uniform tension" and espe-
cially the measurement of breaking stress at the same time, is a complex engineering
task.
One of the greatest scientists and educators in the field of strength of materials
Feodos'ev V.I. in the book [2] wrote:
"The only one method of the all-round homogeneous tension known at present
time is the following: "The previously cooled solid homogeneous ball is quickly heat-
ed. The stress state indicated above will occur in the ball center. Unfortunately this
method is not suitable for investigation of material properties under this state stress,
for example for determining the so-called rupture characteristic".
This method was used by modern scholars [3]. Obviously are the difficulties to de-
fine specific values of the limit of the all-round tensile strength. Strength at all-round
uniform tension in [3] is determined indirectly by finite element method (FEM).
Lately many works have been written which address the issues associated with the
testing of materials under three axial tension. A review of these works is beyond the
scope of this article. However, a large number of such works testify the importance of
studying the properties of materials with uniform three-axis tensile.