CYCLIC SYMMETRY

[Anonymous]

Hi

I am doing topology optimization for a rotating disk. I want to do my optimization with a 360/64 degree of part and apply cyclic symmetry to my part. How can I do that?

Thank you in advance

[etfrench]

Is cyclic symmetry the same as Circular Pattern in Fusion 360?

[Anonymous]

Yes. It is same.

Von meinem iPhone gesendet

[Anonymous]

Yes. It is same.

Von meinem iPhone gesendet

[etfrench]

Does Shape Optimization work for what you need to do?

[Anonymous]

But it doesn't make cicular pattern or cyclic symmetry here in this project. I attached that I'll make optimization. This is just 360/64 of my part

[John_Holtz]

Hi @Anonymous and @etfrench

Cyclic symmetry is related to a circular pattern, but what needs to be done in the analysis is different than what would be done to draw the CAD geometry (using a circular pattern). You can use this page from the Simulation Mechanical documentation to get an understanding of what cyclic symmetry does in an analysis: Cyclic Symmetry.

Cyclic symmetry is an advanced option that Fusion does not have. If the model is really cyclic symmetric, the only option would be to model the entire 360 degrees.

Obviously, your real part is a full disk. But, is your analysis of the 1/64 section really cyclic symmetric, or is it just symmetric? What are the loads on the model?

1. If the loads are radial and/or axial, the analysis can be symmetric. In this case, you can use frictionless constraints on the two cut faces.
2. If the loads include a tangential component, then the analysis does require cyclic symmetry.

[Anonymous]

I tried to explain my boundary conditions in the shown picture. My loads are pressure on the top surface and Rotational force in radial direction. My part should be free just in radial direction and fixed in tangential and axial direction.

[John_Holtz]

Hi @Anonymous

I think that most Fusion users will not understand your references to a cylindrical coordinate system (where "X" is a radial direction, not a global X direction, and so on). And since Fusion does not have cylindrical coordinate systems, we have to think in terms of global XYZ.

Based on your loads, the results will be symmetric about each of the faces as shown in the attached diagram. Thus, cyclic symmetry is not required for this analysis. The way you create the "symmetry" constraints when the face is not perpendicular to X, Y, or Z is to apply a "Constraint > Structural Constraint" and set the "Type" to "Frictionless". The axial restraint (in the global X direction in your model) is not on the symmetry faces -- those faces are free to move in the global X. The X direction is restrained somewhere else on the model (at the inside diameter if this is where the model is attached to a shaft?).

See the attached figure.