Rigid link Error in Calculations - Robot Structural Analysis

[crissyj1999]

I am running the calculations for a concrete floor slab in Robot Structural Analysis and I am getting the error, "Rigid link -  All degrees of freedom released". I would like to know how to resolve this error. Thank you in advance.

[EduardoMeruvia]

Hi @crissyj1999 , 

How did you defined the Rigid Links? Did you release the rigid links degrees of freedom for all of them?

[crissyj1999]

I did not define them at first and still got the error. Then I defined them as a flexible diaphragm and still got the error.

[EduardoMeruvia · Accepted solution]

@crissyj1999, I meant the actual definition of the Rigid links used, see image below on how to access that info. 

You can see in the image that the default diaphragm rigid links its blocked in the UX and UY direction which is normally what you want. But its seems in your case might be ALL unblocked if getting a "All degrees of freedom released" error. 

Also there is some criterior apply to how to use rigid links, I think is best summarise in the Help menu, see link below;

https://help.autodesk.com/view/RSAPRO/2022/ENU/?guid=GUID-88C4C842-5D90-4E85-8F8C-D47D6E474E29

Note: The rigid links option can be used only in the types of structures that allow for rotational degrees of freedom. Therefore, you cannot define a rigid in the following types of structures: 2D truss, 3D truss, stress plane, deformation plane, axisymmetic structures, and volumetric structures.

A node can be defined as a secondary node only in one rigid link. Therefore, the following notation is not correct:

1 2 3 4 LIN 10

1 6 7 LIN 9.

Note: Secondary nodes must not also be defined as rigid type supports. They can be defined as elastic type supports.

Note: Secondary nodes must not be defined as nodes compatible with other nodes. Primary nodes can have compatibility defined with other nodes.

Note: You cannot use a rotated support in the primary node of a rigid link for the selected degrees of freedom.

[crissyj1999]

Thank you for your help! It is working now.