Getting error 38878 from the exported model

sswh2
sswh2 Altair Community Member
edited May 23 in Community Q&A

Hi, I am exporting one patch array (4x4) from CST to FEKO 2023.1. I recreated port and did the union operation after defining material properties. The model status mentioned the model  is valid. But I am getting error 38878 . My model geometry file and the error screenshot is attached here. Kindly fix my error so that I can run my file. File is attached here.

image

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Best Answer

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited May 23 Answer ✓

    Hi @Srabonty Soily,

    Due to the size of the model, memory requirements and runtime are quite large. I will therefore use MLFMM instead of standard MoM. However, I could imagine that FEM could be the most efficient solver here. I will try that as well.

    Best regards,
    Torben

Answers

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited May 21

    Hi Srabonty Soily,

    The recently implemented mesh engine seems to have problems with the very thin PEC regions of the waveguides. If I switch to "legacy mesher", it works.

    image   image

    However, I would really advise simplifying the model. It doesn't really make sense to model 35 µm thick PEC patches with phyisic thickness. Instead, you should just use surfaces, which significantly reduces the number of mesh elements and thus memory and runtime.

    By the way, there is another error in the model: In the waveguides, the exciting wave hits a PEC face (and is reflected), which is not intended:

    image

    I will change the model a little and get back to you later.

    Best regards,
    Torben

  • sswh2
    sswh2 Altair Community Member
    edited May 21

    @Torben Voigt sir thank you! I will wait for your corrected model.

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited May 23 Answer ✓

    Hi @Srabonty Soily,

    Due to the size of the model, memory requirements and runtime are quite large. I will therefore use MLFMM instead of standard MoM. However, I could imagine that FEM could be the most efficient solver here. I will try that as well.

    Best regards,
    Torben

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited May 23

    Hi @Srabonty Soily,

    I would recommend MLFMM with my simplified model, see attached. The model seems to be a little large for FEM. With MLFMM and e.g. 16 parallel processes, only 35 GByte RAM are required, and 11 frequencies are calculated in 15 minutes.

    Best regards,
    Torben

  • sswh2
    sswh2 Altair Community Member
    edited May 21
    Torben Voigt_20420 said:

    Hi @Srabonty Soily,

    I would recommend MLFMM with my simplified model, see attached. The model seems to be a little large for FEM. With MLFMM and e.g. 16 parallel processes, only 35 GByte RAM are required, and 11 frequencies are calculated in 15 minutes.

    Best regards,
    Torben

    Thank you@ Torben Voigt sir. But I found the problem in my array is there is only one waveguide source defined in my model, there should be 16 waveguide source I think.

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited May 22
    Srabonty Soily said:

    Thank you@ Torben Voigt sir. But I found the problem in my array is there is only one waveguide source defined in my model, there should be 16 waveguide source I think.

    Hi @Srabonty Soily,

    In the original model you attached there were 16 waveguide ports but only one waveguide source. I qickly added the other sources as well now, see attached.

    Best regards,
    Torben

  • sswh2
    sswh2 Altair Community Member
    edited May 22
    Torben Voigt_20420 said:

    Hi @Srabonty Soily,

    In the original model you attached there were 16 waveguide ports but only one waveguide source. I qickly added the other sources as well now, see attached.

    Best regards,
    Torben

    @Torben Voigt sir I appreciate it! Thanks! Let me run it.

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