Dear All,
Let me add up something to this question:
Many a times client support standard wants us to use 3 Directional Restraints (3D stops) instead of pure welded anchors and the constructional arrangement used to implement such a 3D stop is normally shown on support standard as a shoe (Y hold down) + guide + Axial stop ; all with 0 mm gap.
In such cases, although Caesar analysis will allow rotations at such supports, but in actual practice, due to the physical arrangement used for such supports, rotational DOF is also restrained although the same was not considered in stress analysis.
How, prudent and logical are such assumptions?
Pankaj.Mandal@fluor.com wrote:
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.
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.
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.
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.
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, Spotsylvania1864)
Yahoo! Groups Links
--------------------------------------------------------------------------------\ ---------------------
--------------------------------------------------------------------------------\ -----------------------
[Non-text portions of this message have been removed]
Yahoo! Groups SponsorADVERTISEMENT
document.write('');
To visit your group on the web, go to: http://groups.yahoo.com/group/PipingDesign/
To unsubscribe from this group, send an email to: PipingDesign-unsubscribe@yahoogroups.com
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
Yahoo! India Matrimony: Find your life partneronline.
[Non-text portions of this message have been removed] Received on Tue Feb 15 23:02:00 2005
This archive was generated by hypermail 2.1.8 : Mon Oct 27 2008 - 20:24:06 EDT