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

SI
Now we seek the pressure of the gases which cause this radial.
strain. For this we find from formula (2.41) e = AR/R = 0.25/92 =
= .72"103. Next we find e and 0:
=• •-
-a' t' = 2,72.1-- _10,4- 10-3 =--7,68-10-';
t; •. -WaT" = 2,72.10-3-- l~610-3 = ,610-3.
According to the known values of relative strains el and 0"
from the graph a = f(C) presented in Fig. 2.37, we find the value
of the stresses
a' = -21.4"107 N/m 2 and a" = 9.4"10 7 N/m 2 .
As mentioned above, we assume that with negative values of
9 the diagram a = f(e) has the same form as at positive values,
only the sign of a changes.
At low values of e the stress cs can be directly calculated
from'formula a0 = EE9, where the Young's modulus for each temper.ture
is taken from the graph presented in Fig. 2.38.
In our case, E' = 1.6"1011 N/m 2 ; E" = 2'1011 N/m 2 .
N
1,8 .(2)~ Cm a.
0,8xn9_ nb
_
,0 1....go t0
Fig. 2.38. Variation in the Young's modulus of various materials.
KEY: (1) N/m 2 ; (2) Steel.
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