(API) Diaphragmer - work with diaphragms in another way

[Romanich]

Hello everyone,

As you might know from this post https://forums.autodesk.com/t5/robot-structural-analysis-forum/diaphragm-problem-to-be-corrected/m-p...

there are several issues with diaphragms in Robot:

1. The master node for the diaphragm is located in the geometric center of the slab. The diaphragm master node should be in the projected center of gravity of the story on the floor slab level.
2. If in the model we have more than one floor slab in the same level, the diaphragm will be created for each slab individually. The diaphragm should be one for each level.
3. It is not possible to assign loads to the master node and get results (eigenvectors etc.). Also, this node is not considered in FE mesh. The master node should be accessible as a common regular node in Robot.
   
   

While Robot development team is still sleeping waiting for financing improving performance, I would like to present the solution to the above-mentioned issues – the Diaphragmer.

The Diaphragmer is now live in the Autodesk App Store:

https://apps.autodesk.com/RSA/en/Detail/Index?id=8768390536116652588&appLang=en&os=Win64

How to use:

Read this article 

Please watch this short video with a live demonstration of Diaphragmer possibilities:

[Romanich]

Hi Alex,

The Diaphragmer does not calculate the locations of the diaphragm centers. All information extracted from the Robot model.

BTW, I tried to download your models but without success.

[Anonymous]

Hi @Romanich 

Thanks for the quick response.

Noted, the data is extracted from Robot, but somehow I still get these strange results.

I will try to send you the files via Wetransfer. Please follow below wetransfer link to the Robot files:

Download link https://we.tl/t-9NxczEtx26

1 item

Robot-20201019T064924Z-001.zip 59.1 MB

Many thanks,
Alex

[Romanich]

Hi Alex,

1. Why did you use Robot rigid diaphragms along with the Diaphragmer approach in the model As per Diaphragmer.rtd? 

2. Load to mass conversion settings are not the same

[Anonymous]

Hi Romanich,

1. Rigid diaphragms are not assigned to any node. I had made some checks before with rigid diaphragms and later, when I changed to flexible diaphragms, I did not bother to delete the rigid diaphragms from the list of rigid links. You can check this at: "Tables" > "Rigid Links"

2. Same as above, I had made some checks before and forgot to change back the settings because I noticed that it does not make any difference.
The only difference is "add to Global Mass" and "add to Modal". Otherwise, the same masses are added in "mass conversion".

The problem is still present. There is a negligible difference in reactions between two models, but there is a huge difference in total modal mass.

I made small adjustments to models as per your comments:
- rigid diaphragms deleted from list of rigid links
- live load deleted as it is not part of this discussion
- load to mass settings matched

Download link
https://we.tl/t-8bSjuXByQx
2 items
201020 As per Diaphragmer.rtd
119 MB
201020 BT 74 [Robot Diaph].rtd
119 MB

[Romanich]

Hi Alex,

My results for the model with the Diaphragmer approach attached. 

In case if something needs to be tested it is much better to do it on a simple model.

[Anonymous]

Hi Romanich,

Yes, those numbers seem correct.

Would you mind pointing me in the right direction as to what corrections have you made in order to get the right values?

This is not a test. This is part of an actual project I am working on at the moment.

Thanks,

Alex

[Romanich]

Hi Alex,

Please check the model

https://we.tl/t-vYRize1mjO

[Anonymous]

Thanks a lot, Roman!

It's all clear now.

I understand your first reply now. The one you wrote few days back. Diaphragmer is not to be used with "slab-rigid diaphragm" slab calculation type. That is why I got those confusing support remnants from the diaphragm automatically generated by Robot. You converted the "slab-rigid diaphragms" to "shells" and then created the diaphragm links.

Thanks again,
Alex