CYCLIC SYMMETRY Error when Slave/Master contain some nodes from fixed surface

Good Morning,

I have some trouble with symmetry.
I have 1/4th of a symmetry plate which is attacked by gravity. I created a support at the green surface, a Master Surface and a Slave Surface with nodes.

I want to use symmetry, thus I used the *CYCLIC SYMMETRY Card. Unfortunately, it doesn’t work. I get the following error message.

ERROR in cascade: the DOF corresponding to node 1 in direction 1 is detected on the dependent side of a MPC and a SPC.

If I understand it correctly, it is not allowed to have the same points in my Master/Slave and in my support surface because they have different ways to calculate the boundaries. However, if I remove the support the spooles solver read the input and starts.

Here is some part of my file:

*Surface, Name=Master, Type=Node
Internal-1_Master
*Surface, Name=Slave, Type=Node
Internal-2_Slave

*TIE,CYCLIC SYMMETRY,POSITION TOLERANCE=1.,NAME=T1
Slave, Master
*CYCLIC SYMMETRY MODEL, N=4,NGRAPH=4
0.,0.,0.,0.,0.,-1.

*Step
*Static

*Boundary, op=New
*Boundary
Internal_Selection-1_Disp_rot-1, 1, 1, 0
Internal_Selection-1_Disp_rot-1, 2, 2, 0
Internal_Selection-1_Disp_rot-1, 3, 3, 0

*Dload
Solid_part-1, GRAV, 9810, 0, 0, -1

Is there a way to solve my problem with symmetry? I read something about the *EQUATION card but I haven’t really understood the use of it and how to use it.

Calculix: 2.16
OS: Windows
GUI: PrePoMax v0.9

I wish you all a nice day!

There could be trouble, If you use
nodes with *Boundary and the same nodes
with another card like in a set for *TIE master & slave
(except *Cload,…)

You can use *BOUNDARY (“a SPC”) on nodes of the master surface but not the slave (“the dependent side of a MPC”). It’s not needed on slave nodes since the slaves automatically follow their corresponding masters’ constraints.

2 Likes

Thank you for your answer. And actually it makes sence. I removed all the constrains from the slave and it works now. Thanks a lot!