Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Nozzle 2D shell analysis acc. to EN 13445-3

Nozzle 2D shell analysis acc. to EN 13445-3

Nozzle 2D shell analysis acc. to EN 13445-3

Hello all,

I have a trouble assessing the FEA results of a set-in nozzle on a dished end.
Design pressure of a vessel p = 40 atu = 40,53 bar; temperature T = 100°C.

Due to changed pipe routing the existing vessel's nozzle should be checked against the loads from piping, but high stresses due to internal pressure lead me to further questions.

Analysis is done with ROHR2fesu module according to EN 13445-3 standard.
The method is based on 2D shell elements.

I do not understand how exactly the junction of a nozzle with a shell is defined in the FE model.
In my specific case/example, I have a nozzle/jacket according to Figure 1.

Figure 1

From the cross section (Figure 2) it can be seen that the junction is made in the median point of a shell wall. That is why defined pressure of element No. 4998 is 0 bar(g). However, the nozzle element above, which is still located in the shell wall have pressure 40 bar(g).
Is this a wrong simplification and can the calculation be verified this way? What about welds on both sides of the jacket and the elements that are still located in the shell wall?

If I consider only internal pressure the nozzle is already overloaded, even if I classify these elements as local.
I am thinking about ignoring internal pressure loads for the area of the nozzle located in the dished end wall. Would this be the correct apporach?

Thank you in advance!

RE: Nozzle 2D shell analysis acc. to EN 13445-3

I don’t know the capabilities of this software but in such cases, it might be a good idea to use solid elements for the junction itself - either with mixed mesh or with submodeling approach. Then you won’t have to worry about the inaccuracies caused by assumptions introduced with shell elements and you will still be able to use them for less critical regions of the model.

RE: Nozzle 2D shell analysis acc. to EN 13445-3

Thanks for the answer.
Unfortunately, the software is very limited. This is an add-on to the base software which is intended for the pipe stress analysis.
It is mostly used for piping elements - circular, elliptic and oval shapes using shell elements - only shell elements.

RE: Nozzle 2D shell analysis acc. to EN 13445-3

Then you have the wrong tool to perform the work. You will need either a different tool or you may need to contract out the work. If the latter, please ensure that the consultant/engineer is well-versed in the EN-13445 methodologies.

RE: Nozzle 2D shell analysis acc. to EN 13445-3

I wouldn't say it is the wrong tool. The software is designed for this type of problems and it is common to use shell theory for this verifications.
I think it is more the question of an interpretation, knowledge and experience of a 13445-3 standard and of shell theory for this type of calculations (pressure vessel design).
Perhaps I should move this thread to another forum, Boiler and Pressure Vessel engineering.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close