Learning Forum

[mrivero]

Hi everyone, 

I'm having some problems and doubts with the aplication of symmetry in my model. The model consist of a sandwich of plates (made of different materials and different thickness) connected by beam connectors, between each plate friction contact is defined. 

1. Can I apply 2 symmetry regions in order to have 1/4 of the whole model? I'm not getting the same stress results. I don't know if friction contact is supported. 
2. Symmetry should be apply to the model in DesignModuler or I can define the symmetry region directly in Mechanical workbench?
3. I define a initial adjustment in each beam connector, but some beam connectors are situated on the plane of symmetry: should I reduce its area by half?

I look forward to any help,

thanks!

[mrivero]

Another issue, how can I know the pretension load of the bolts if I'm defining it by adjustment? I've tried it by bolt results but I can only choose bolt pretension ones so there is none to select. 

[Akshay Maniyar]

Hi Marina,

1. Applying two symmetry regions to model a quarter of the whole structure is possible, but you must ensure that both the geometry and the loads and boundary conditions are symmetric across the planes you are using for symmetry. If you're not seeing the same stress results, it could be due to the friction contacts, as they might introduce asymmetry depending on how they behave under the applied loads. It's important to verify that the frictional behavior does not violate the symmetry conditions.
2.  Symmetry can be applied either in the Design Modeler or directly in the Mechanical Workbench. The key is to ensure that the symmetry boundary conditions are correctly applied in the Mechanical Workbench to reflect the intended symmetry of the model.
   For other CAD tools, you can cut the geometry into it and then apply symmetry boundary conditions in mechanical.
3.  For beam connectors situated on the plane of symmetry, you typically do not need to reduce their area by half. Instead, you should ensure that the boundary conditions on the symmetry planes are correctly applied. This might involve constraining the appropriate degrees of freedom to simulate the effect of the full model.

You can check the working load of the beam connections by inserting bolt pretension result or you can check axial force by using beam probe.

Thanks,

Akshay Maniyar