This forum uses cookies This forum makes use of cookies to store your login information if you are registered, and your last visit if you are not. Cookies are small text documents stored on your computer; the cookies set by this forum can only be used on this website and pose no security risk. Cookies on this forum also track the specific topics you have read and when you last read them. Please confirm whether you accept or reject these cookies being set.A cookie will be stored in your browser regardless of choice to prevent you being asked this question again. You will be able to change your cookie settings at any time using the link in the footer.

• 0 Vote(s) - 0 Average
• 1
• 2
• 3
• 4
• 5
Calculation internal pressure for thick-walled pipes
18-12-2012, 11:20 AM, (This post was last modified: 17-10-2013, 03:14 PM by shaswin.)
 shaswin Senior Member Posts: 357 Threads: 189 Joined: Dec 2008 Reputation: 0
Calculation internal pressure for thick-walled pipes
According to NEN 3651:2012 paragraph 8.5.2.1 there are two different formulas for the calculation of the hoop stress.

There is a different between a thin-walled and thick-walled pipe.

Formula hoop stress for a thin-walled pipe     :

Formula hoop stress for a thick-walled pipe     :

Ple4Win (v4.2.2 build 12112) uses always the thin-walled pipe formula. There should be a difference between a thin-walled and thick-walled pipe in the calculation of the hoop stress.
31-12-2012, 03:35 PM,
 ir KW Radder Moderator Posts: 22 Threads: 2 Joined: Sep 2008 Reputation: 0
RE: Calculation internal pressure for thick walled pipes
It should be noticed that the formulae for the hoop stress are given for the so-called 'simplified' strength calculation. In general NEN 3651:2012 paragraph 8.3.1 refers to NEN 3650 parts 1 to 5 for the (hoop) stress calculation, where only the formula for the thin-walled pipe is given.

The formula for the thick-walled pipe changes to the formula for the thin-walled pipe if D/d approaches infinity.
Originally PLE has been developed for the strength and stability calculation of 'thin-walled' pipelines.
The hoop stress calculation in the NEN 3650 module is based on NEN 3650-2:2012. Nevertheless it is always good to apply a more accurate formula.

31-12-2012, 07:09 PM, (This post was last modified: 13-05-2016, 01:06 PM by shaswin.)
 shaswin Senior Member Posts: 357 Threads: 189 Joined: Dec 2008 Reputation: 0
RE: Calculation internal pressure for thick walled pipes
No problem Rien.

When you will apply this formulae in Ple4Win the ratio D/T column from the PIPEDIM output table should be changed. D shouldn't be the external diameter but the average diameter and T should be T-MIN. So the ratio should be Dg/T-MIN.
The wanings should be also updated when changed.

This part of the helpfile should also be updated: Ref: Tables Reference > Output Tables > Pipe dimension data [PIPEDIM] > Table error description / ID: H310523
12-05-2016, 02:47 PM,
 ir KW Radder Moderator Posts: 22 Threads: 2 Joined: Sep 2008 Reputation: 0
RE: Calculation internal pressure for thick-walled pipes
Hi Shaswin,

This is to inform you that we are investigating the possibilities to incorporate the behaviour of a thick-walled pipe in PLE. These pipes may occur especially in offshore environments with high internal pressure.
It is not only a matter of a different hoop stress, but it has an effect on internal forces and upheaval buckling risks as well. Of importance is the DNV code DNV-OS-F101 for submarine pipeline systems.
13-05-2016, 01:11 PM, (This post was last modified: 13-05-2016, 01:12 PM by shaswin.)
 shaswin Senior Member Posts: 357 Threads: 189 Joined: Dec 2008 Reputation: 0
RE: Calculation internal pressure for thick-walled pipes
Nice.
20-05-2016, 11:52 AM,
 Dr. J Foerster Moderator Posts: 215 Threads: 6 Joined: Sep 2008 Reputation: 0
RE: Calculation internal pressure for thick-walled pipes
This issue has also been assigned to ticket no J-1885, see this topic for more about thick-walled pipelines

Forum Jump:

Users browsing this thread: 1 Guest(s)