Meshing Errors

[alexeding]

We are trying to mesh and solve our fuselage model, which is constructed from 0.625” diameter pipes with 0.035” walls: 

However, as you can see we get both out of memory and self intersection errors. The model does not appear to have interferences. This screenshot was after running the mesh at 0.1 in on the absolute size setting, and larger meshing sizes caused many self-intersection errors. We 3D sketched our model then used Fusion’s pipe tool, however, we do have thin walls. How can we rectify the errors? 

Our forces are each in the hundreds of pounds, reaching ~1,000 lbf. Is that part of the issue? 

We’d appreciate any help. Attached is our file in the form of an .fd3 but please let us know if a different format is preferred. 

Thank you!

[mcmillr · Accepted solution]

The pipes are so thin that even if you obtained a mesh I am not sure an accurate analysis will be produced. The mesher warns about this. The main issue with meshing, aside from the thin geometry, is the pipe intersections. When you boolean the pipes like this it creates all sorts of sliver geometry which would not exist in the real world. You could try cutting each subsequent pipe section with the previous section, deleting any 'extra' orphaned bodies that are produced, then doing a join to get a cleaner interface. You could also forgo the join and use a bonded contact. You can try this on a subsection to see how well it works before applying it to the entire model.

If you still get meshing issues you could try setting the element order to linear under advanced mesh settings, that might simplify the meshing process. That might contribute more to a loss of accuracy though. Ideally something like this should be run using beam or shell elements, but Fusion does not support those element types at this time.