General Mechanical

General Mechanical

How to perform submodeling in electromagnetic problem / Low Freq Electromagnetics / Mech APDL

    • artemiy_shamkin
      Subscriber

      Hello,

      please help me to setup emag case with submodeling (Low freq electromagnetics in Mechanical APDL)

      3D problem, current conduction, edge-based analysis.

      Cut-boundaries are laying in the air domain with single DOF: AZ (magnetic vector potential).

      Mapping that DOF to the boundary of the submodel gives non-reasonable results.

      Please advise how to setup the problem.

    • Erik Kostson
      Ansys Employee


      Unfortunately, there is nothing about submodeling in the low frequency electromagnetics apdl help manual so this procedure is not documented, and so I would thus not know if it is even possible - so I would not be able to advice thus since we do not have any official documentation that we can refer you to.
      Perhaps though some users have looked into this and can offer some perspective and advice.
      All the best of luck
      Erik
    • artemiy_shamkin
      Subscriber

      Hi Erik, could you please check with Bill Bulat, I`m sure he knows the answer. Best, --Artemiy
    • Erik Kostson
      Ansys Employee


      If you would like someone (e.g., wrbulat) to look at your post, then you can make them aware of your question by adding a tag @ likeand so they might be able to provide some further help.

      All the best

      Erik


    • artemiy_shamkin
      Subscriber
      Thanks for the advice.

      Hi Bill, could you please help me with the submodeling for the electromagnetic problem. Please see the post at the top.
      Best --Artemiy
    • Bill Bulat
      Ansys Employee
      Hi Artemiy I'm sorry I didn't respond earlier. I'm still investigating how to do this and need to discuss further with the developer. It's NOT straightforward. The CBDOF command does not apply to edge-based DOF used by SOLID236/237. Please bear with me while I try to block out some time to work on this.
      Best regards Bill

    • artemiy_shamkin
      Subscriber
      @wrbulat,
      Hi Bill,
      yep I found it non-straightforward too, as we need to satisfy magnetic flux through the area, having magnetic vector potential as a DOF.
      I have found slides from the Ansys conference 2006 demonstrating MVP transferring between same surface with dissimilar meshes. My problem is a bit more complicated.
      https://www.yumpu.com/en/document/read/40975896/interface-procedure-for-magnetic-edge-elements-procedure-ansys


      Thank you for your help. Looking forward you answer,
      Best,
      Artemiy
    • Bill Bulat
      Ansys Employee
      Hi Artemiy Yes, Martin Hanke (CADFEM) is the undisputed king of interfacing edge-flux formulated emag elements. I just looked at another example he created in which a 2D planar Maxwell model of a rotating motor served as the coarse mesh full model. Time-varying Maxwell results were interpolated onto the boundaries of a 3D emag submodel including an electrically conductive bolt that was omitted from the Maxwell model. Eddy currents and Joule heating were induced in the bolt by the time-varying B field. It was all done in Workbench though... I know you work in MAPDL.
      So, if there aren't any ferromagnetic regions in your model, you can use the 3D MVP (SOLID236 with undocumented keyopt(3)=2). This is far simpler because the formulation is nodal-based... you can use CBDOF command just as you can with any other engineering discipline in MAPDL. Is your system "iron"-free?
      Bill
      • volkov
        Subscriber

        Dear Mr. Bulat (@wrbulat),

        I have similar kind of a problem as Mr. Shamkin but with some differences. First of all, I'm not tied to a certain ANSYS product: Ansys Electronics Desktop, Ansys Workbench or Ansys Emag would do. Secondly, in my problem i have ferromagnetic regions. Ferromagnetics can have linear, nonlinear or nonlinear anisotropic magnetic properties.

        Rough illustration of what i want to achieve is depicted on a drawing below.

        In the model i have:

        • some sort of magnetic field source (e.g. coil);
        • electrical steel packet (ES) (mur near 10000);
        • conctructional steel plate laying on a ES packet (mur<1000);
        • air domain, which contains all of the above mentioned pieces.

        On the first step i want to calculate field distribution on constructional steel plate (or on air near the plate) with rough mesh.

        On the second step i want to use magnetic field distribution from the first step, and with finer mesh calculate eddy currents (and corresponding losses) in constructional steel plate.

        Is there by chance any tutorials, manuals or some other documents describing procedure or something which could help my with solving this problem?

        Looking forward to your reply! Searching for working electromagnetic submodelling method for Ansys since 2016, Will be so much obliged if you could give me some insights!

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