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#62013 - 02/06/15 10:46 AM My Code Stress Seems High
LeviM Offline
Member

Registered: 11/14/12
Posts: 73
Loc: Texas, U.S.A
Hello,

I'm getting a 245.67% stress ratio (sustained case) at an intersection node, which seems a bit high. The intersection consists of a 4" sch40 pipe with a 1" sch80 pipe branch and I've set the "SIFS & Tees" on the intersection to "8 - Socket". Attached is a screen shot of the intersection in question, the stress table, global element forces extended report, and my attempt to calculate the stress with Excel.

What am I missing?

-Levi


Attachments
Stress check.png



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#62016 - 02/06/15 04:29 PM Re: My Code Stress Seems High [Re: LeviM]
Richard Ay Offline
Member

Registered: 12/13/99
Posts: 6226
Loc: Houston, Texas, USA
There isn't enough info to tell. Please open a Support Request on Smart Support and send in your job file.
_________________________
Regards,
Richard Ay - Consultant

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#62060 - 02/11/15 01:40 PM Re: My Code Stress Seems High [Re: LeviM]
LeviM Offline
Member

Registered: 11/14/12
Posts: 73
Loc: Texas, U.S.A
I might put in a support request at some point, but shouldn't I be able to find the sustained code stress with the moments and pipe dimensions?

Something like this:

[ft*lb] [in*lb]
Mx= 250.5 3006
My= -36.3 -435.6
Mz= 8.6 103.2

I/c[in^3.]= 0.1606
SIF= 1.3
Allowable Stress= 20000

Mr= 3039.150144 =SQRT((Mx)^2+(My)^2+(Mz)^2)

σ= 18923.72444 =Mr/(I/c)

σ*SIF= 24600.84177
Stress %= 123.0042088



Edited by LeviM (02/11/15 01:47 PM)

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#62061 - 02/11/15 02:22 PM Re: My Code Stress Seems High [Re: LeviM]
Dave Diehl Offline
Member

Registered: 12/14/99
Posts: 2382
Loc: Houston, TX, USA
Too many questions remain but I'll give it a try...

You are running B31.1, you have corrosion defined (about 0.08 inches), and you have all cases corroded?
_________________________
Dave Diehl

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#62064 - 02/11/15 03:43 PM Re: My Code Stress Seems High [Re: LeviM]
LeviM Offline
Member

Registered: 11/14/12
Posts: 73
Loc: Texas, U.S.A
I'm using B31.3 and my corrosion is set at... ohwwww... 0.125 in. That seems like it could be a bit of a problem, seeing as the wall thickness is only 0.179 in. I didn't think to set the corrosion and it just grabbed the value from a thicker pipe.

Well, I better add corrosion to my pre-run check list. Thank you.

-Levi

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#62065 - 02/11/15 04:05 PM Re: My Code Stress Seems High [Re: LeviM]
LeviM Offline
Member

Registered: 11/14/12
Posts: 73
Loc: Texas, U.S.A
Yes! That fixed it. Thank you!

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