Civil Engineering Reference
In-Depth Information
Fig. 5.21
Ti-G2 example
EEC profile (
v
=
12.7 mm/
min) [
11
]. Depicted is a
general shape of an EEC
profile for Ti-G2 at this
particular speed
1
0.8
0.6
0.24
ξ = 0.46 ·
S
%
0.4
0.2
0
0.00
20.00
40.00
60.00
80.00
100.00
% Stroke Completed
Fig. 5.22
Stainless Steel
304 example EEC profile
(
v
=
12.7 mm/min) [
11
].
Depicted is a general shape
of an EEC profile for SS304
at this particular speed
0.6
0.5
0.4
0.3
ξ
=
0.00075·
S
%
2.2
0.2
0.1
0
0.00
20.00
40.00
60.00
80.00
100.00
% Stroke Completed
determines the overall shape of the profile. In particular, if the exponential term
is less than one, the profile will be convex-shaped, and if the exponential term is
greater than one, the profile will be concave-shaped.
The concave/convex shapes of the profiles can also be explained visually by
examining the mechanical power profiles of the EAF tests run on each of the materi-
als. Figure
5.23
shows the mechanical power profiles of a conventional compression
test and an EAF compression test for the Ti-G2 material. The difference between
the baseline and EAF power profiles, at discrete points, becomes slightly smaller or
remains the same as the test progresses. This explains the profile in Fig.
5.21
, where
minimal increase is seen toward the end of the test, when compared to the increases
at the beginning. Figure
5.24
displays the mechanical power profiles for EAF tests
on the SS304 material. Contrary to the Ti-G2 material, the difference in the baseline
and EAF power profiles increases as the tests progress. This leads to the profile in
Fig.
5.22
, where the largest EEC increase is witnessed toward the end of the tests.
Two properties of the metals can be responsible for the difference in the shapes
of the EEC profiles: the effect of temperature increase on the strength of the
metal, and the effect of alloying. The strength of the titanium begins to immedi-
ate decrease as temperature is increased, whereas the strength of the stainless steel
does not show much of sensitivity to temperature until higher temperatures are
