Custom Cross-section in RFEM

Product Support
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1

Hello,

I have a construction that requires a modified section, simply a standard section with a modified web thickness. A very minor adaption. Is it possible to create this section on RFEM6 without the need for RSECTION?

Thank you in advance

3

Hi _lobo,

You can create any custom cross-section using RSECTION:
:backhand_index_pointing_right: RSECTION Online Manual

Alternatively, you can use a cross-section from our cross-section library and define it as a parametric cross-section:
:backhand_index_pointing_right: FAQ 005311 – Parametric Cross-Sections

This allows you to either design your section completely freely or start from an existing library shape and adjust it to your specific requirements. :light_bulb:

Best regards
Stefan Hoffmann

4

Thank you @stefan.hoffmann. I currently don't have an RSECTION license. At the moment it makes little sense to get one just for this one section.

With the second method, after creating a parametric cross-section, is it possible to save it in the library so that it can be used in built-up cross-sections?

5

Hi _lobo,

:white_check_mark: You can save the cross-sections as described here:
:backhand_index_pointing_right: Online Manual – RSTAB 9: Cross-Sections

Please note that this function is file-specific.

To make your workflow easier, we recommend creating a template model and using it for future projects. You can find more information here:
:backhand_index_pointing_right: Online Manual – RFEM 6: Template Models

:light_bulb: Tip: Working with templates helps you quickly start new projects with predefined cross-sections and other settings.

Best regards
Stefan Hoffmann

1 Like
6

Hi @stefan.hoffmann,

Thank you for your reply.

However, I am still having an issue. Say for instance, I need to create an IPE180 with a modified web. I create the section and I save it in my sections with a new name. So far all works. But, if I need to create a built up cross section of two IPEs, I don't see an option to select my custom cross-section

image
image1741Ă—1032 73.6 KB

Am I missing something or is this indeed not possible at the moment?

7

Hi _lobo,

After you added the section, you should be able to load it by clicking here:

image
image1407Ă—862 59.5 KB

Best regards
Stefan Hoffmann

8

Hi @stefan.hoffmann,

Yes, that is indeed true for normal cross-section. But if you try to create a built up cross section, there is no such button for the sections that compose the built-up (partial cross-section).

image
image1741Ă—1032 86.5 KB

9

Hi _lobo,

I am sorry, but I do not get your issue. If you save this section into “My sections”, you can open it by step 2 and 3. It is there for me:

image
image1552Ă—2629 281 KB

Best regards
Stefan Hoffmann

10

Stefan,

What I am trying to do is:

  1. Define an IPE180 section with a web of say 8 mm.
  2. Save this as a custom section
  3. I need this custom section to be defined as partial cross section of a built-up section of 2xIPE180 with web of 8 mm.

In this screenshot, you are saving a built-up section with a normal IPE from the library in "My sections".
Basically, I need both of the IPEs of the built up cross-section to have 8 mm webs.

I hope this is a bit more clear and I apologize for any confusion.

11

Hi _lobo,

You can currently either use an IPE and save it modified or create your built up section with the given/ listed IPE.
Its not yet intended to mix this and have a hybrid custom section as you explain.

I do not feel like there is a big pro in using a built up section, as the shear coupling is not that good. You can rather use a single section and this FAQ in order to have double members:

https://www.dlubal.com/en/support-and-learning/support/faq/005607

Best regards
Stefan Hoffmann

12

Thank you for your answer Stefan, this makes it clear now.

But it also raises more questions. Out of curiosity, why do you say the shear coupling in a built up section is not that good? And second, in the FAQ that you sent, there is a line release added, but it is not explained how the hinge parameters influence the creation of double members. Would be great if you could plan in the future a technical documentation on this.

13

Hi _lobo,

thanks for coming back on the issue.

I simply don’t feel like the shear coupling will represent the interaction as good as a line release can do. You can mostlikely only simulate full or no coupling.

Line release values cannot be explained deeply by us. The springs you add for the different DOF will be in need to be calculated by an engineer and then added to the input.

Best regards
Stefan Hoffmann