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

In some cases, it is assumed that the reduction.in rigidity for
a perforated plate occurs as a result of the variation in E and p
of the plate. For the problems which we are studying, it is feasible
to attribute the decrease in rigidity to the decrease in plate
thickness, which we shall designate h., and we shall find from the
relation D.
-- --- y - -- i4 :
D
h
ii.isVi , (2.78)
As has been mentioned, the value of y depends upon the geometric
dimensions of the perforated plate and is .determined from formula
[26]
y=O,25(3+k) I- (
(2.79)
wheire d is
s is
k is
the diameter of the opening;
the step of the opening;
the plate rigidity coefficient;
k
1,41
1+ s(2.80)
The variation in the coefficient k as a function of ratio of
plate thickness h to width of connecting neck (s - d) is shodn in
Fig. 2.59a. As is apparent from formula (2.80), it varies f,,om
zero to -1.
The variation in the coefficient y as a function of the ratio
of the diameters of the perforation opening to their step is shown
in Fig. 2.59b. Usually the values of y fall within 0.1 to 0.5,
which corresponds to the ratio (d/s) = 0.2-0.9.
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