Learning Forum

[a.alhalabi]

Hi,

I am trying to work on static structure for impact stress analysis on the ulna bone of the forearm using Ansys Workbench for my university project. I have a CT Scanned STL file of the bone, which I downloaded online (link for the 3D model is available on request)

The issue is, whenever I try to run the model, the geometry part is checked with a tick and is shown as successful, I try to open up mechanical for analysis and the model successfully opens up. However, whenever I try to mesh the model, the following error message pops up: "the mesh generation did not complete due to poor quality elements or incorrect input"

I am unsure of what I should do and how I can resolve this issue?

 

If this is an issue regarding the fact that the Ansys Student license is limit please let me know, since if that is the case I would have to draw a simpler model using CAD myself.

[Rob]

Can you open the scan geometry and check the shape. CT/MRI derrived models can have regions that are badly defined or have very small sharp features that pose problems for meshing. Staff are not permitted to open/download files so please post images. 

[a.alhalabi]

[Rob]

Carefully check the geometry at the +z & -z ends. You're looking for folds or flat sections where the scan pixelation has produced slivers or the like.  You may find the CT extraction tool has some functions for fixing these issues. 

[peteroznewman]

Open the STL file in SpaceClaim and use the tools on the Facets tab to improve the facet quality and potentially use the Shrinkwrap feature to automatically fit a skin over the facets. The skin forms a solid body that will be much easier to mesh. Watch this video: https://www.youtube.com/watch?v=KWGVkilcMAE