What settings should I set to simulate two parallelepipeds of different materials (a dielectric and a metal) coupled together?

Martina Falchi

Hi guys, I need to simulate two coupled solids composed of two different materials. One is a dielectric, the other a metal. I have tried changing the settings from the region properties, varying between SEP and VEP, but I can't get any results because I only get error messages. Does anyone know how to help me?

 

Torben Voigt

no problem, here it is.

Torben Voigt

Hi @Martina Falchi ,

What kind of error messages do you get?

In principle, no special settings are necessary. You may want to make sure that the faces of the metallic part are metallic, while its region is freespace (metal is only applied to faces, dielectrics are applied to regions).

You surely know that touching geometry parts must always be in a union, so that the mesher doesn't create two independent meshes.

Feel free to attach your model, if you can't solve it.

Best regards,
Torben

Martina Falchi

Hi Torben,

first of all thank you for your advices! Now I'll try to be more precise and I'll attach my model to better show you the situation.

The errors I got were about mixing VEP and SEP solver in a not very rigorous way I think, and maybe because I was using the methods in a wrong way.

As you can see in the model attached I need to simulate two parallelepipeds, the first will be in a material like concrete, the second a steel. Then I have to simulate a "hole" inside the steel, so I need to subtract for example another smaller parallelepiped from the steel one.

So if I well understand:

- to the concrete parallelepiped I assign the material to the region;

- for the steel one I assign free space to the region and the steel to the faces (in this case, I am asked to set a thickness, since I need to simulate a "full" structure even if I assign free space, maybe I have to assign a thickness equal to the width/lenght of the structure?)

- for what concern the "hole", in which way should I set this region?

Should I assign the materials  first and then make the union of the three parallelepipeds or is it indifferent?

Sorry for all these questions, but I hope you can help!

Best regards,

Martina

Torben Voigt

Hu @Martina Falchi ,

Basically, here's what you need to do:

• Create a cuboid1 for the concrete
• Create a cubuid2 for the steel (can probably use PEC here for most applications)
• Set the region of cuboid1 to "concrete"
• Set the region of cuboid2 to "PEC"
• Union both cuboids
• Create a cuboid for the hole
• Subtract the new cuboid from the Union

Note, it doesn't matter if you assign materials at the beginning or the end. Have you already checked out the GettingStarted Guide? It usually helps new users very quickly with the first basic steps.

If you could attach the model (.cfx) I could easily set this up for you.

Best regards,
Torben

Martina Falchi

Thank you Torben,

I would like to use steel for Cuboid2 in order to create a more realistic scenario.

I attach the .cfx file, if you are so kind to set it for me.

For what concerns the guide, yesterday I was trying to find there the questions I asked you, but I preferred to talk to someone more experienced.

Thank you again,

Martina

Torben Voigt

Hi @Martina Falchi ,

Here's the model. Note, I created it with Feko version 2019.3 (that's the oldest version I have installed). You might want to consider an update

Best regars,
Torben

Martina Falchi

Thank you Torben,

Can I ask you the last thing: can you set cuboid2 with a steel following the advices you gave me in your first answer?

I would like to make a simulation using the steel, but I'm not so sure about how I have to set the material to the faces and which thickness.

It is the very last thing!

Thanks a lot,

Martina

Torben Voigt

no problem, here it is.

Martina Falchi

Thanks a lot for all your advices!

Have a very good day,

Martina