asdeasoft.net

Good evening,
I have a problem with the assignment of master point and slave point for a rigid diaphragm. When I use the mentioned command, everything is right. However, when I run the analysis, there is a python error in the terminal in which point out "Different NDF on same node". I think that could be a problem in the definition of the interaction, though do not know where and I appreciate you help.
Thanks in advance

Are you using a rigidDiaphragm in a 2D problem? If that is the case, you can't. RigidDiaphragm only work in 3D. The 2D counterpart would be an EqualDOF in Ux

If this is not the case, can you post your SDF file here? We will have a look.

Dear STKO,

For rigid diaphragm in 2D case, besides using Equal Ux, do I need to set Rz constraint for the floor master nodes?
In 3D, I found that you constrained Uz, Rx, Ry for the floor master nodes, which means that the slabs are not allowed to rotate.
I found that the seismic behaviors of 2 cases are totally different as in attached figures.

Thank for your support,
Buu

For rigid diaphragm in 2D case, besides using Equal Ux, do I need to set Rz constraint for the floor master nodes?
In 3D, I found that you constrained Uz, Rx, Ry for the floor master nodes, which means that the slabs are not allowed to

I do that in 3D only when the master node is not part of the structure.
In your case you don't need to create an extra master node.
You just need to select, for each floor, 1 random-master (for example the vertex on the left) and all other edges as slave.
Then you equalDOF only Ux