SimScale CAE Forum

CHT analysis of a PCB with 3 components


#1

Hi!
I’ve been trying to make this project work but there is something wrong. I don’t know what it could be and some help would be great. I want to study the heat behaviour of this PCB but every time I run the simulation this message appears:

I’m suspicious about this message on the meshing log but I don’t know how to fix it.

This is the link of my project and I hope someone can show me the mistake.
https://www.simscale.com/workbench/beta?pid=3955413222366232148&mi=run%3A3%2Csimulation%3A7&mt=SIMULATION_RUN

Thanks!


#2

Well, I’m trying to upload the images but an error message keeps appearing (they are pursuiting me)

The first image appears when the simulation is starting and shows this: “The Run1 simulation is failed. Please, check the Event Log and Solver Log for mor details”

The second images is a print screen of the ending part of the meshing log. There you can read a message that says: "The following face pairs are only in partial contact and are not imposed as automatic interfaces… "

I hope this can supply the lack of images…

Regards!


#3

Hi @YohanCurbelo!

Let me just tag my colleagues @Get_Barried and @vgon_alves here who might give you some advice on your geometry and mesh setup to ensure that the simulation works.

Cheers,

Jousef


#4

These messages have been recently added to help debug problematic interfaces. A face pair, should be identical to be interfaced, if a face does not match the face it is touching, then it might only be partially interfaced. The solution is to ensure each face pair matches, this might involve face splitting. Here is an example in your geometry:

The face belonging to the fluid touches two faces visible in the image, one being the top of the PCB and the other also on top of the PCB but split apparently around the component. These faces should either be merged, or the fluid faces split to match the PCB faces.

Alternatively, you could define the interfaces manually in the simulation setup.

Best,
Darren


#5

Hi Jousef!
Thanks for helping me. I’ll waiting news about your colleagues… :wink:
Best
Yohan


#6

Hi Darren!
Firs at all, thanks for helping me. Your point makes a lot of sense and I’m gonna try it but I’m not sure about if it’s the key becasuse I already defined the interfaces manually in the simulation setup. Anyway, I’ll make the split perfectly matched and I’ll let you know about the results
Best
Yohan


#7

Hi @YohanCurbelo, yes I agree not the key but was just posting to give information about the mesh warnings and what they mean. The simulation errored straigh away which is unnerving. But I noticed two things here, the number of cores is set to 4, which might not be enough for the mesh size, and lack of memory (amount of ram also scales with instance size) but there is also no heat source, I dont know if the simulation fails with no source or weather it would just solve with no dT, I would attempt with a heat source just incase.

But as Jousef said if there are any better suggestions feel free to chim in.

Best,
Darren


#8

@YohanCurbelo, I saw your runs were still failing, I copied your project and deleted the manual interfaces and the simulation proceeded, therefore the interfaces are unfortunately the issue, I suggest revisiting the geometry again, ensuring that the highlighted issues are removed and then remesh, hopefully no partialals will be pressent and you can proceed without the need of manually interfacing them.

Best,
Darren


#9

Yes, they failed. Ok, I’ll do that. Thanks a lot for the attention. When I got the new analysis I’ll post about it.
Best regards!
Yohan