01.07.2014 Views

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

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

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

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

2 1z or 2..<br />

.• .. :. • C .2,e. .. . .<br />

In this case,<br />

I ~~<br />

Xi6= -. A.P• ,,,.p<br />

O2<br />

If the rigidity <strong>of</strong> the rotor is greater by one order than the rigidity<br />

<strong>of</strong> the bearing (k 1 = O.lc), the rctor can be considered absolutely<br />

rigid. Error in determining the natural angular frequency, in this<br />

case, does not exceed 5% <strong>and</strong> we can assume that the natural frequency<br />

<strong>of</strong> vibrations is proportional to /A-. Since the ratio wc//W = n/n 1<br />

= n /nlx does not depend on pressure drop in the bearing, the revolutions<br />

<strong>of</strong> autovibration appearance are also propoi'tional to /•:<br />

Sn.ix<br />

In hydrostatic bearings the role <strong>of</strong> the damping coefficient is<br />

played by expression n - n 1 = (nx - n )VJj i.e., with forced<br />

vibrations the value <strong>of</strong> damping in hydrostatic bearings is proportional<br />

to VAFp.-<br />

For a rigid rotor the formulas for amplitude <strong>and</strong> phase <strong>of</strong><br />

forced vibrations (3.164) assume the form<br />

I"I<br />

(n -hi.))AP +,,<br />

tgc,=<br />

wl (.r - nIx) V Ap<br />

-404

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!