Re: thermal movement calculation

From: <George>
Date: Mon Sep 22 2003 - 08:41:00 EDT

Hello Chris:
AMEN on the comments about engineers vs. computer operators! Thermal growth doesn't necessarily mean a lot - it's relative growth between solidly anchored elements that counts. Along the same line, I have seen piping vibration on a compressor that (I swear) was 200 mils p/p. But it was at 5 cps, on a 30 foot line that was only anchored at one end. Result, movement was gross, but strain gauge check was near nothing.

Comment: An engineer tells you how to do it, a lawyer comes along and tells you that you can't....

George McKinney

• Original Message -----
  From: Christopher Wright
  To: ?
  Sent: Saturday, September 20, 2003 1:02 PM
  Subject: RE: [PipingDesign] thermal movement calculation
  

>So it is important in support & nozzle loads point of view
> that what exactly to follow in caeser & in practical too??

I had a tough time with your syntax, but if the quoted sentence means
what I think it means, you're right on. Software, FEA or CAESAR gives
results. They aren't good or bad results until the engineering with
responsibility for the job has validated the results agaisnt the actual
installation and said that they're good or bad. Software users who are
disconnected from the real world of fabrication and the actual service
environment have a lot of very strange notions about what goes on in the
real world. My experience is that a very good case could be made that
such people aren't really engineers. They may know something about
engineering, but that something lacks a necessary perspective. I've done
both and I've had a lot of opportunities to see how the computer monitor
pictures differ remarkably from what goes on during the third shift.

That's not to say that the software is no good or that a user needs to
understand the source code before he can trust it. Whether you do manual
calculations on the back of an envelope or use FEA of Code software, no
one who calls himself an engineer or a designer should be under the
illusion that his calculations are anything but a thumbnail sketch of a
very complicated reality.

Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw@skypoint.com | this distance" (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)
<a href="http://www.skypoint.com/~chrisw">http://www.skypoint.com/~chrisw</a>

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[Non-text portions of this message have been removed] Received on Mon Sep 22 08:41:00 2003