Unable to import CATIA products into CFD

[Anonymous]

I encounter the following error when I try to import an assembly from CATIA into CFD.

"Conversion from imported geometry to analysis model failed."

[matt.bemis]

Hi @Anonymous,

Thanks for reaching out to us on the forums! What version of Catia is it? Is the geometry complicated? To make sure CFD is working correctly, you could try importing a simple block that was made in Catia. If that works then you know this is a geometry specific issue, not a question of CAD connections/functionality. 

Feel free to attach the Catia file here too. I am happy to take a look and see what's going on. 

Thanks,

[Anonymous]

I have been able to open catia Part files in CFD.

[matt.bemis]

Hi @Anonymous,

Okay, good to know. The failure you are facing is probably due to very detailed geometry. What does the mode look like? Are there very small edges/surfaces? I suggest defeaturing the model or breaking the model into chunks. You can try to import individual pieces and this will help you understand the location of the problem. 

[Anonymous]

You're probably right. The geometry is fairly complex. Let me know if the attached file works for you. I've attached a part file that I created from the product.

[matt.bemis]

@Anonymous,

I downloaded the file but I get an error when I try to open the file in SimStudio Tools and Inventor. Both of those CAD tools support CATParts, so I am not positive what is going on. Would it be possible for you to save your model out as a step file? Perhaps I would have more success opening a neutral file format.

[Anonymous]

LEt me know if you have any luck with this.

[Jon.Wilde]

I had one of our CAD specialists here look into this - we are unable to open either of these files in anything we have.

Just thought I would share as I am not sure this is a CFD issue yet but more of a CAD one.

[Anonymous]

Have you been able to open it on CATIA? I have been able to open it on CATIA without any error messages. What might the problem or a potential fix be? I tried to assemble all the parts in CFD Sim Tools, but I was not able to find a tool to constrain the parts. As a result I ended up with tiny gaps that resulted in failed meshing.

[matt.bemis]

Hi @Anonymous,

I don't have access to CATIA so I will wait to see what my coworkers say about the CAD file. It's a bit hard to troubleshoot the meshing issue if I can't see the file. Did you have surface refinement turned on? That usually helps the chances of getting a successful mesh.

[Jon.Wilde]

Is it possible to share a few images of what the part looks like? Maybe there is something glaring that we could immediately highlight as an issue?

Did you test a cube as Matt suggested above? Start simple to rule out any simple issues 🙂

[Anonymous]

I have added a couple of screenshots. Hope these help.

[Anonymous]

Hey,

Here's what I did. Since my assembly is not all that complex. I started assembling it in Sim Tools. Now I'm a sim tools noob and don't know how to constrain my objects in it. So there are some tiny gaps in it. I wonder if that's causing any issues in CFD. I keep getting a General Meshing Error (60/503).

I have included a link to the folder with the files: https://1drv.ms/f/s!AliFPRkDFlg3hJsKfo8rFyOhPWv_Aw

[Jon.Wilde]

Good idea 🙂

You can overlap parts in Sim Studio if it helps, CFD will then break them up into multi bodies - this saves having tiny gaps.

You do need to avoid the small gaps - also note the very thin overlap between your two front parts, they really ought to have a clean meeting surface.

Suppress all of the solids from the mesh, no need to mesh them at all here.

Do you definitely need the small holes in the fins, allowing the air to flow inside the unit?

Also, your Boundary Conditions are over constraining the model, remove the outlet velocity and use a P=0

Eventually, your air volume will need to be far larger, I guess you know that though and that this is a simple test?

Could you run a 1/4 model here too? It would really save on meshing - you are going to need a LOT of mesh 🙂

Hope that helps!

Jon

[Anonymous]

Let me try some of these things and get back to you.

[Amal.C]

Hi @Anonymous,

Can you please provide an update regarding this topic?

Thanks,

Amal

[Anonymous]

Hey @Amal.C,

I was unable to figure out a solution to my problem. So I resorted to a workaround. I imported the parts into Sim Tools and assembled them there. I then opened up the assembly in Surface Wrap and create a volume mesh there. I then imported the mesh into CFD and ran the simulations.