Design and Stress Analysis of Extraterrestrial ... - The Black Vault

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The constants B and n are determined in processing the experimental
creep curve. For example, on Fig. 1.27a the dependence o'f creep
deforiAation e on time and stress is shown for steel.' The sect.qn of
unsteady creep is disregarded.
75 A
10 5 210 -
5 I -..
0 5 70 O45o,5 Us'.10',ad 3 . 5
a) . 6.1O•'a/cN?
Fig. 1.27. Determining 6onstants of the creep curve.
Steel content: C = 0.31; Mn = 0.54; Ni 2.05; Crl=
= 0.83.
2 = Ni 2 ac=h 2 2
Designations: M/2 MN/m2; vac h; aac2 = daN/cm
From these curves we determine the rates corresponding to
steady creep = cmn (,the subscript "min" will be dropped in thl.
future). The value of creep rate-is presented in Table 1.1!. We map
these points on a logarithmic grid (Fig. -1.27b) and dx~aw a straight
line so that it occupies, as nearly as possible, the "average"
position between them.
has the form
Since relationship (1.16) for steady creep
t Ban, I , (1.17)
the tangent of the slope angle of a straight line In I in B +,n
agrees with index n; from Fig. 1.27b we find n = 2.3. Afteý this,
from the points of the straight line we find B.; The values of
in o
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