Shreedhar,
I didn't get your point: "............if it not welded, it will tend to relax."
In general, some amount of erection tolerance exists for a pipe support. For example, a "guide" is in most cases "guide with a gap" and hence some degree of rotation is always let free. However what I was trying to prove that wherever we have large rotation across a guide, erection tolerance does play a governing role and as a stress analyst one needs to take care of that too.
Pankaj.
"shreedhar" <shivapuji@mis.co.ae>
02/15/05 12:20 PM
Please respond to PipingDesign
To: <PipingDesign@yahoogroups.com>
cc:
Subject: Re: [PipingDesign] Pipe supports
.
Dear Pankaj,
Below listed are my views of the subject ...
Best wishes,
Shreedhar Shivapuji.
>
> As a common practice, pipe supports such as guides and axial stops are
> modeled in stress analysis software as point contact supports i.e. it
> restricts movements only and allows free rotation.
[Another thing to be noticed ... physically, shoes are guided which is
somewhere below the centreline of the pipe. But in the analysis we guide
them along the centreline.]
>
> It we really go into construction of these supports, in most cases, it
> locks one or more additional degree of freedom, not accounted for in our
> analysis.
[No. There won't restriction on rotation unless the support is welded.]
>
> Let's take an example of a simple pipe guide on shoe, locking movement
in
> say X-axis (let X be north, Z be east and Y - up). If we consider no gap
> in the pipe support, rotation about Y-axis is also locked. Now my
question
> to all is whether this locked rotation is considered in your analysis.
[Again, if it not welded, it will tend to relax. Hence, there won't be
restriction on rotation.]
>
> I did a similar test case for a pipe support near equipment. The result
> was quite disturbing. Introducing a rotational stop at support point
> resulted in a huge moment, which surely would not make our structural
> colleagues happy. On the other hand, if we introduced some gap in the
> support (which is the most probable case), rotational effect was
> nullified, but loads on equipment nozzle were increased considerably.
[Rotational restraint can be used if the equipment can be protected (by
keeping within the nozzle allowables). But construction of such a support
can be quite intricate.]
>
> Expert opinion solicited.
>
> Regards,
> "A CENTRAL ASIAN FRIEND"
>
>
>
>
>
>
> Christopher Wright <chrisw@skypoint.com>
> 02/15/05 10:42 AM
> Please respond to PipingDesign
>
>
> To: PipingDesign@yahoogroups.com
> cc:
> Subject: Re: [PipingDesign] Looking for job as a Piping
Designer / Draftsman
> .
>
>
>
>
> On Feb 14, 2005, at 10:48 PM, Steve McKenzie wrote:
>
> > until you can communicate in an asian language as well as our asian
> > friends can communicate in English, I suggest that you tread warily.
> I owe a lot of people an apology for that crack. I can't help the fact
> that I really get spun up by poor writing and bad netiquette, and I
> won't be so hypocritical as to pretend I don't, but I am sorry I
> offended more people than those who had it coming.
>
> I will say this. You can skate over to any of the Usenet newsgroups to
> get an idea of what happens to the signal to noise ratio when people
> don't observe long-standing standards on netiquette. I really think we
> need to stay on topic and to quoting properly and reply in readable
> english, which is the language of the list.
> Christopher Wright P.E. |"They couldn't hit an elephant at
> chrisw@skypoint.com | this distance" (last words of Gen.
> .......................................| John Sedgwick, Spotsylvania
> 1864)
> http://www.skypoint.com/~chrisw/
>
>
>
>
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> http://www.pipingoffice.us/
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[Non-text portions of this message have been removed] Received on Tue Feb 15 02:52:00 2005
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