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

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<strong>The</strong>se formulas show that on the free face maximum thermal<br />

stress acts in a circular direction. If we add stresses a from<br />

formula (5.34) with stresses a. caused by moments M. <strong>and</strong> force T,<br />

[formula (5.36)], we obtain<br />

Eau~(____ S-- F + (I-<br />

-. (5.37)<br />

When p = 0.3 this stress is 25% greater than the stress (5.34)<br />

calculated for points at a great distance from the faces.<br />

In brittle material we should, thus, fear cracks from the ends<br />

<strong>of</strong> the shell <strong>and</strong> not in the middle. Figure 5.25c <strong>and</strong> 5.26 show<br />

stress diagrams for the end <strong>and</strong> the center part <strong>of</strong> the shell having<br />

a temperature gradient through the thickness.<br />

rmdi<br />

MMV<br />

Fig. 5,26. <strong>The</strong>rmal stresses Fig. 5.27. Moments acting on an<br />

in a cylindrical shell,<br />

element <strong>of</strong> a "conical shell.";<br />

<strong>Analysis</strong> <strong>of</strong> conical shells<br />

A conical shell experiences internal pressure <strong>and</strong> thermal loadings.<br />

Let us consider an axisymmetric problem. <strong>The</strong>refore, the unknown<br />

stresses <strong>and</strong> strains <strong>of</strong> the elements are functions only <strong>of</strong> coordinate<br />

556

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