Part within assembly will not mesh

[benjamin.kingPK8LG]

Good Morning,

I have been trying to get a part i have conceptualised to mesh within my vibration test assembly. I was attempting to setup up a Normal modes test case for 140Hz to 2000Hz at 60g.

I have followed all the work flows that i could find on the forum for work arounds see following:

1. Make sure the part has a Idealization.

2. Make sure the part thats not meshing CON-EXP-15438 has no geometry error CTRL+F7

3. Make sure the Assembly that contains CON-EXP-15438 has no geometry error CTRL+F7

(To big to screen shot but no bad parts or features).

4. CON-EXP-15438 meshes on its own in the part simulation environment.

5. Interogated part feature tree to remove unused sketches and geometry.

6. Exported to stp file and imported as single body (CON-EXP-15439) and it meshed once and never worked again within the assembly.

7. Tried varying mesh sizes no effect.

Can anyone help any further work arounds or investigations i can perform? Parts described attached.

@John _ Holtz

[John_Holtz]

Hi @benjamin.kingPK8LG 

All three files mesh for me using Inventor Nastran version 2023.2.0. Your assembly may not mesh because it includes other parts, and the other parts change the overall size of the model. (I had to "skip" the missing parts when I opened the assembly.) My suspicion is the overall size of the model changes some internal tolerance which either helps or hurts when meshing.

You should try to hide all the parts in the assembly except for "CON-EXP-15438.ipt". With the model mesh if that is the only part visible in the assembly?

In my opinion, the "compound curved surfaces" where the fillets meet are problematic for meshing. This one where a 1 mm , 2 mm, and 3 mm fillet all meet are likely to be related to the problem. If possible, you should suppress on the fillets to see if it meshes. (If it does mesh, then you can decide if having results with no fillets is better than having no results with fillets.)

You might be able to "mesh over" some of those small imperfections by changing the "Mesh > Mesh Settings > Settings > Suppress Short Features" and "Min Feature Angle" to large values (such as 20% and 20 degrees).

Let us know what you find out.

John

Also, there are a few small features that can be creating problems. One is shown in the image above, and another is shown in the image below. If these can be removed, it may help. 

[benjamin.kingPK8LG · Accepted solution]

Hi John,

Thanks for taking a look at the model, ive gone through defeatured the model removing the fillets and then meshed and added a feature one by one until i found the offending feature. Which turned out to be the fillet between the webbs and the main diameter. I also created a dirived model which was a single body and that also seems to have helped. 

After taking both these steps ive managed to get the model to mesh initally with the mesh stepping over or larger than the fillets modelled but ill put a mesh control on them after i get some initial results to refine them.

Cheers

Ben