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<DIV><FONT face=Arial size=2>Me thinks there's a fine line betwixt anile, and
cautious.</FONT></DIV>
<DIV><FONT face=Arial size=2>Actually, it's not all that fine......</FONT></DIV>
<DIV> </DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=gfowler@raytheon.com href="mailto:gfowler@raytheon.com">Gray E
Fowler</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, February 03, 2005 1:16
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> MK belldeal-actuallly switchin"
to Natural Frequency</DIV>
<DIV><BR></DIV><BR><FONT size=3>"Agree w/ John about using foam as a vibration
damper. Also, someone much wiser than me pointed out that whatever is
installed should NOT be halfway, 1/4 way, or any reasonable fraction of the
pushrod length because these may end up as stationary nodes in the vibrating
rod, and end up doing no good. </FONT>
<P><FONT size=3>Rick</FONT><FONT face=sans-serif size=2>"</FONT>
<P>
<P><FONT face=sans-serif size=2>Rick</FONT>
<P><FONT face=sans-serif size=2>Could happen but consider this.....The
resonance or flutter results from a combination of factors. One is the modulus
of the item and one is the mass. In the case of our push rod scenario, the cf
rod has a consistent stiffness the length of the rod, so that is constant, but
the longer the rod the easier it is to buckle. A full length rod has a certain
mass and a half length rod (foam in the middle) has half that mass. The
apparent stiffness of the half rod is greater and the mass is less therefore
what make a full length rod resonate most likely will not make the half rod do
the same. In addition, having the rod in contact with the foam dampens the
resonance, as opposed to a situation where the rod is hard fastened, and
therfore sets up a new set of resonance factor based on the mass and modulus
again.</FONT>
<P><FONT face=sans-serif size=2>Hopefully this makes sense...I absorbed this
primitive knowledge hanging around true stress weenies...
<BR><BR><BR><BR>Gray Fowler<BR>Principal Chemical Engineer<BR>Composites
Engineering</FONT></P></BLOCKQUOTE></BODY></HTML>