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

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<strong>The</strong> question <strong>of</strong> system stability can be solved using the Routh-<br />

Hurwitz criterion. For system stability it is necessary <strong>and</strong><br />

sufficient that a matrix made up <strong>of</strong> the coefficients <strong>of</strong> the frequency<br />

equation <strong>and</strong> the even-order diagonal minors <strong>of</strong> this matrix be<br />

positive. <strong>The</strong> Routh-Hurwitz matrix, in this case, has the form<br />

-2, w -, own2 0 0<br />

0 (,2+W 2 0 -(02(02 0 0<br />

1 2 - 1 2<br />

0o OMI 021t O 1020<br />

2 0<br />

0 0 w+0) 2 0 -0 2 0--V<br />

2 1'2 0<br />

0 0 -ai -6 1 O* n (on,(d<br />

12<br />

For system stability the foll*owing conditions are necessary<br />

<strong>and</strong> sufficient:<br />

(w.24) >0; ,n(.,4,, O.,>0;<br />

2 • "2(,- 1 +2) >O<br />

- w) 2 h2(.)8 (02+ W;) +n 2 e4Oci)>0,~2''<br />

then the system is<br />

stable when<br />

,t>O, WK n, (3.165)<br />

For the self-excitation rate w* = (n)/(nl)wo 0 , in all roots<br />

s <strong>of</strong> the characteristic equation n > 0,<br />

the vibrations described<br />

by expression (3.163) will be attenuating <strong>and</strong> only forced vibrations<br />

will exist in the system. When w > wc in the system, along with<br />

c<br />

forced vibrations there will also be autovibrations described by<br />

expression (3.163).<br />

<strong>The</strong> quantity s on the boundary <strong>of</strong> the autovibrations can be<br />

found from equation (3.164) with allowance for the fact that<br />

on the boundary wn 1 = W0n:<br />

401

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