Learning Forum

[sentenza]

Hi to all, i want to realize a linear static analysis for a shaft 1400mm long, 130mm diameter with keyways and seeger groove walls. I have torsional load and bending load. What's the best element to use for this type of problems? For me it's very simple to use tets elements, but i would try hexa element.

Can you explain how to obtain a very small meshing with hexa and what to do to realize a fine mesh in groove walls or keyways. Thanks a lot

 

 

[peteroznewman]

To get a hex mesh, slice the solid at each change in cross-section. So on each groove wall for example. The keyways are more challenging. Please reply with an image of the geometry. How does the keyway end, with a half cylinder or a ramp?  In either case, you would slice out a solid at the the end of the straight walls of the keyway and also slice a short distance past the keyway end. You don't want to slice tangent to the end of the keyway. That piece may need the solid sliced through the center of the keyway and some other planes.

If the shaft has any chamfers at either end, delete those faces to maintain a uniform cross-section to the end.

If you want to do all that, reply with your progress.  If this sounds like too much work, go with the tet elements.

[sentenza]

thanks for your advice, Peter

Let's start from the beginning not considering groove walls and keyways......the first problem I found when I slice with planes perpendicular to shaft axis I can't apply sweep method (or multizone) to each single parts but just to the ends. If I divide shaft with concentric cylinders I can sweep and obtain Hexa elements.      Is that correct or is there something I didn't understand?

[peteroznewman]

If you are slicing in DesignModeler, you have to select all the parts in the outline and right click to Form New Part.

If you are slicing in SpaceClaim, you have to go to the Workbench tab and click on the Share button.

Doing either of these enables Shared Topology. That is how the mesh connects across the multiple bodies.

Once you do that, you only need to define Sweep on one end of the shaft, and Shared Topology will carry that through the rest of the parts.

[sentenza]

i formed a new part in both cases, but sweep worked only with conentric cylinders. I don't understand why

[peteroznewman]

You can attach the Workbench Archive .wbpz file to your reply and I will take a look.

[sentenza]

thank you, here's a very simple case with just one keyway. I removed all planes and sliced part

[peteroznewman]

I would say that all this slicing is not worth the effort compared with the ease of a tet mesh, but here it is...

[sentenza]

thank you, although i'm not be able to open attached file, I understood how to put slicing planes