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

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

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Bend w is an elastic bend <strong>of</strong> the shell as a result <strong>of</strong> pressure<br />

PRt" This bend is known from relationship (5.13): w* = -rcAt.<br />

Equating those values <strong>of</strong> w*, we obtain the pressure P~t' which holds<br />

the shell in<br />

a rigid bond:<br />

a compressed state as a result <strong>of</strong> the application <strong>of</strong><br />

r2<br />

I<br />

<strong>and</strong><br />

PRI= -7'a7A.<br />

r<br />

<strong>The</strong> obtained shell deformation w* = -w* = -raAt <strong>and</strong> reaction<br />

y t<br />

forces -PRt differ from the actual since actually there is no rigid<br />

attachment. <strong>The</strong> shell is free.<br />

b) In order to obtain the pure deformation <strong>of</strong> the shell, we<br />

should apply the load arising in the shell during its attachment<br />

but with opposite sign. We find the bend <strong>of</strong> the shell from the<br />

reaction Pt = -PRt from equation<br />

A.D D rD (5.14)<br />

c) <strong>The</strong> sum <strong>of</strong> the two deformations obtained from equations<br />

(5.13) <strong>and</strong> (5.14), which we shall designate Wp, gives us the elastic<br />

component <strong>of</strong> total shell deformation during its thermal loading:<br />

wy = -rcAt + wp.<br />

loads:<br />

Hence we find the stresses arising in<br />

the shell from thermal<br />

r r (5.15)<br />

d) <strong>The</strong> numerical value <strong>of</strong> total thermal deformation by heating<br />

a free shell is found from relationship<br />

w = wt + Wy = raAt - raAt + w = wp. (5.16)<br />

524

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