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Adding constraints with different local coordinates at the same node for different solutions

Hello guys,

 

I am currently working on a project where I need to define local coordinate systems for correct definition of the boudary conditions.

It is working properly for the first solution.

But I need to simulate different load cases which differ in the orientation of the coordinates at the fixation points.

For my second solution I tried to define another boundary condition on the same node as used in solution 1 but assign a differnet local coordinate system. Unfortunately it looks like that NX is not allowing this.

 

Does anybody of you knows how to overcome this issue?

 

The only thing I can do is to copy the model in a seperate file and change there the local coordinate system.

 

Thanks in advance.

 

Regards,

 

Georg

4 REPLIES

Re: Adding constraints with different local coordinates at the same node for different solutions

Hello!,

You need to define a new SOLUTION with the option "SUBCASE CONSTRAINTS" instead "GLOBAL CONSTRAINTS", this way you will be able to combine freely loads with constrainst, ALL in the same NX NASTRAN input deck, impressing!!.

 

 

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: Adding constraints with different local coordinates at the same node for different solutions

The displacement system is a property of the grid and cannot be changed during an analysis. Changing spc's by subcase only allows you to change the dof or displacement magnitude, not the displacement csys.

Solution
Solution
Accepted by topic author GStrickner
‎08-26-2015 04:32 AM

Re: Adding constraints with different local coordinates at the same node for different solutions

Georg,

 

At a minimum you will have to use multiple SIM files. The SIM supports editing of the displacement coordinate system assignments. In the menus look for Edit, Node, Assign Nodal Coordinate System. This is similar to assigning node coordinate systems in the FEM, but it is limited to just the displacement system (and not the reference system). The edit will create an Override Container under the FEM node, thus indicating that the change was made.

 

The advantage here is that if you should decide to edit the mesh, you only have to edit it once. All of your SIM files will update accordingly. I wouldn't want to be in your situation if it required copying all FEM each time along with the SIM.

 

Regards,

Mark

 

 

Mark Lamping

Simulation Product Management

Product Engineering Software

 

Siemens Industry Sector

Siemens Product Lifecycle Management Software Inc.

mark.lamping@siemens.com

Re: Adding constraints with different local coordinates at the same node for different solutions

I got the below error when I had a cylindrical constraint and this solved the issue!!