Autodesk Robot Structural Analysis

[#1]

Hi,

I have tried to simulate a gap between two shell elements in a bridge deck slab (composite bridge steel girder / concrete slab), but the iteration is always endless.

I would like to simulate a gap of 0,4 mm between prefabricated concrete deck elements on top of a steel girder. I have tried using "compatible nodes" and the "gap" option, but the iteration is endless. Does anyone have a suggestions how to model a closing gap resulting in contact between two shell elements after a deformation of 0,X mm ?

[#2]

Hi,

have you tried changing the method of non-linear iterations from default BFGS to full Newton-Raphson, i.e. activating update of stiffness matrix after each iteration in parameters of load cases which are not convergent:

If it will not help please attach the file after saving without results and compressing to ZIP format. The reason may be in some mistakes in definition of compatible nodes.

Regards,

[#3]

Hi again,

Thanks for the advice. Unfortunately it did not solve my problem, so there might be something wrong in the definition of compatible nodes.

I attach a zip.file of the model.

[#4]

Hi,

are you sure that you have changed the settings as I have recommended in the provious post?

When I have done it in parameters of load case 9 (see the attached modification of your model) the analysis is convergent.

Attached model without results to reduce its size.

BTW: I recommend updating RSA 2011 without any Service Pack (v.24.0.0) with the latest SP6 (to v.24.0.6). It can be done using Live Update or downloading the update from the site below (rememeber to download SP coherent with RSA or RSAPro):

http://usa.autodesk.com/adsk/servlet/ps/dl/index?siteID=123112&id=2334435&linkID=13140816

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If this post answer your question please click "Accept as Solution". It will help everyone to find answer more quickly!

Best regards,

[#5]

Thanks a lot!

I had just changed the parameters in the "job preferences - structural analysis", not in the load case settings.

Now everything works fine!

[#6]

You are welcome

Change in Job Preferences is related only to default setting for new created load cases and not for already existing load cases.

For existing load cases it is also possible to "import" settings from job preferences:

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If this post answer your question please click "Accept as Solution". It will help everyone to find answer more quickly!

Regards,