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Valued Contributor
sonyablade2010
Posts: 61
Registered: ‎09-24-2012
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frame Member offsets (Rigid links; RLinks)

770 Views, 11 Replies
12-13-2012 12:12 PM

Dear All,

 

I'd like to know how the RSA is handling the offsets for frame members, for example suppose that there is an ordinary vertical column and if there are horizontal beams connecting to top node of that column with different offset settings. Then how the RSA deals with that, visual observation reveals that RSA creates artificial lever arm for differently connecting beams.

 

Your englightment will be appreciated.

 

Regards,

 

 

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Artur.Kosakowski
Posts: 4,769
Registered: ‎12-17-2010

Re: frame Member offsets

12-13-2012 11:58 PM in reply to: sonyablade2010

You may say that an offset is a virtual rigid link with no real generation of 'the other' node.

 

 

http://docs.autodesk.com/RSA/2013/ENU/filesROBOT/GUID-DFB075D8-BD24-4946-8D4F-3175E93DEBA3.htm

 

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.



Artur Kosakowski
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Valued Contributor
sonyablade2010
Posts: 61
Registered: ‎09-24-2012

Re: frame Member offsets

12-14-2012 05:02 AM in reply to: Artur.Kosakowski

Thanks a lot indeed,

 

So basically how this maps into FEM theory implemented in RSA, by assuming that this rigid link has same as the beam properties Ix, Iy, Iz , A,   poisson ratio etc.. except that Young Modulus is much more higher than the beam ? 

 

Is my assumption correct ?

 

 

Regards,

 

 

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Artur.Kosakowski
Posts: 4,769
Registered: ‎12-17-2010

Re: frame Member offsets

12-14-2012 05:40 AM in reply to: sonyablade2010

For RLink approach yes, other wise the kinematic relations method (exact solution) is used.



Artur Kosakowski
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Valued Contributor
sonyablade2010
Posts: 61
Registered: ‎09-24-2012

Re: frame Member offsets

12-14-2012 05:48 AM in reply to: Artur.Kosakowski

Do we have the kinematic approach in RSA? Because I haven't seen such an option in any of RSA toolbar. Can you elaborate it ?

 

Regards,

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Artur.Kosakowski
Posts: 4,769
Registered: ‎12-17-2010

Re: frame Member offsets

12-14-2012 07:09 AM in reply to: sonyablade2010

They are used if RLinks are switched off. Mind that Sparse and Multi-threaded solvers due to their architecture force use of RLinks regardless of the setting in Job Preferences.

 

RLinks.PNG



Artur Kosakowski
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Distinguished Contributor
Tuctas
Posts: 172
Registered: ‎10-10-2012

Re: frame Member offsets

12-19-2012 04:02 AM in reply to: sonyablade2010

  Hi,

 

  This feature in which we are able to model an offset by a kinematic constraining rather than using Rlinks is really interesting, i wasn't aware that we were able to do that..

 

  Can we do such a modeling (by kinematic constrains) for a diaphragm too? (i.e instead of assigning Rlinks between master node and slave nodes)? I mean, can we just constrain some d.o.f of selected nodes?

 

 

 

 

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Artur.Kosakowski
Posts: 4,769
Registered: ‎12-17-2010

Re: frame Member offsets

12-19-2012 05:22 AM in reply to: Tuctas
Can we do such a modeling (by kinematic constrains) for a diaphragm too?  

 

Yes, the general rules I described above apply. You have to switch off RLinks and set the solver as Frontal, Skyline or Iterative.

 

 



Artur Kosakowski
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Distinguished Contributor
Tuctas
Posts: 172
Registered: ‎10-10-2012

Re: frame Member offsets

12-19-2012 05:54 AM in reply to: sonyablade2010

  Thank you for your reply Artur,

 

  Do you mean that even if we model manually a diaphragm by defining manually rigid links between nodes, we can switch off the Rlinks in Job Preferences and then there would be kinematic constrains?

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Artur.Kosakowski
Posts: 4,769
Registered: ‎12-17-2010

Re: frame Member offsets

12-19-2012 05:56 AM in reply to: Tuctas

Provided you use the solvers mentioned above.



Artur Kosakowski
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