Defining and using Cyl CS in WB Dyna

- August 1, 2022 at 7:02 pm
  
  shah.493
  Subscriber
  
  One problem we have run into with WB2021 is that we cannot create cylindrical coordinate systems in WB for Dyna app. In our problem we need to apply BCs in radial and theta directions in one of our simulations.
  Do you know if there is a workaround or plans to fix this in future releases?
- August 1, 2022 at 7:57 pm
  Reno Genest
  Ansys Employee
  Hello,
  You can create BCs in a cylindrical coordinate system in LS-PrePost by using the NODE option with *BOUNDARY_SPC_NODE. See the following example and video:
```
http://ftp.lstc.com/anonymous/outgoing/support/FAQ_kw/bc_in_cylindrical_coord_system.tar

With the NODE option, each node has its own local coordinate system to apply constraints in the  radial and tangential direction.

These coordinate systems are created automatically by LSPP:



In the image above, x=radial, y=tangential, and z=axial.

I think cylindrical coordinate systems are in the plan for WB LS-DYNA, but I am not sure when it will happen.

Reno.
```
- August 1, 2022 at 8:46 pm
  
  shah.493
  Subscriber
  
  Yes, we know it can be done in LS Pre/Post but can such BCs get imported to WB since we are doing everything in WB.
- August 1, 2022 at 9:43 pm
  
  Reno Genest
  Ansys Employee
  
  You can create the BCs in LSPP as described above, save the .k file with LSPP. Then, open the .k file with a text editor and copy/paste the *DEFINE_CURVE, *DEFINE_VECTOR, *DEFINE_COORDINATE_NODES, and *BOUNDARY_PRESCRIBED_MOTION_NODE into a command snippet in Mechanical.
  In the following example, I apply a velocity in the tangential direction on the top edge and I constrained the bottom edge in the tangential direction only. This uses the DOF=4 option on *BOUNDARY_PRESCRIBED_MOTION_NODE to use a vector to define the tangential direction:
  
  Let me know if this helps or not.
  
  Reno.