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

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satisfies the bounaary conditions <strong>of</strong> the r oblem (this function is<br />

already normalized).<br />

Fig. 3.27. Integration <strong>of</strong><br />

the f(x) function by the<br />

trapezoid method.<br />

<strong>The</strong> analysis will use formula (3.25).<br />

performed according to the trapezoid method.'<br />

Integration will be<br />

Integration in lines (8)<br />

<strong>and</strong> (15) begins from the blade tip<br />

since according to the boundary conditions when = 1, the shearing<br />

force is equal to zero. Integrat:!on in.lines (9) <strong>and</strong> (16) is also<br />

performed from the blade tip (wh.2n i = 1 the bending moment is zero).<br />

In lines (11), (18) <strong>and</strong> (12), (19) we integrate from the beginning<br />

<strong>of</strong> reading (since when z - 0 the angle <strong>of</strong> pitch <strong>and</strong> the deflection<br />

<strong>of</strong> the blade are equal to zero).<br />

Both the zero <strong>and</strong> the subsequent approximations <strong>of</strong> function<br />

uare drawn on the graph (Fig. 3.26).<br />

<strong>The</strong> angular velocity <strong>of</strong> natural blade vibrations is determined<br />

from formula (3.45), taking into account the remote factor:<br />

'As we know, the formula <strong>of</strong> trapezoids has the following form<br />

(if the number <strong>of</strong> points <strong>of</strong> division is equal to n) (see Fig. 3.27)<br />

f (.) dx - Ax (fo +- fI + 2f2 +... + 2f -, + f J), where Ax=- .<br />

2 n<br />

<strong>The</strong> greater n the more accurate the formula.<br />

278

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