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Implement a user defined Magnetic Field to do further Simulation with

    • Joshua Igl
      Subscriber

      Hello,

      I am new to Ansys and for my current project I am wondering if there is any possibility to implement a user defined magnetic field in Ansys to do further simulation with.

      For my Application, let's say I have a matrix of Tesla-Values which i want to transfer into Ansys and maybe interpolate values in between the given ones. I want to use this magnetic field to simulate the effects it is having on other objects. Is there any way this is possible?

      I was able to create nearly homogenic B-Fields by creating Helmholtz-Coils or a simple long coil with currents in Maxwell. But with this approach I can't create the exact representation of the magnetic field I want to achieve and work with.

      I would be grateful for any help, i have posted this in electronics channel before, but GLUO recommended to try it here, because he thinks it is possible in LS-Dyna. 

      Thank you in advance, 

      Joshua

    • Aniket
      Forum Moderator

      Hi Joshua, Can you please provide link to previous discussion here?

      -Aniket

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      • Joshua Igl
        Subscriber

        Hi Aniket, sure. 

        /forum/forums/topic/implement-a-user-defined-magnetic-field-to-do-further-simulation-with/

        Joshua

    • Jim Day
      Ansys Employee

      I’ll preface my reply by stating that this topic is not in my wheelhouse so I contacted an LS-DYNA EM expert on this matter.   LS-DYNA has an integrated EM solver, which, if I understand the expert’s reply, should make it unnecessary to import a magnetic field.

      Please refer to the examples at http://dynaexamples.com/em/eddycurr .  There is an example there called TEAM 4, which is a simple application of an external magnetic field on a rigid piece.  There are also other example(s) there in which a coil applies a field to a workpiece.
       
      dynalook.com has some pertinent papers that can be found using the search tool and those papers can be downloaded.
       
      Information can also be found on YouTube by typing ‘lsdyna multiphysics’.

      • Joshua Igl
        Subscriber

        Hello Jim, 

        thank you for your reply and your investigation in that matter. It may seem unnecessary, but in our use-case we are experimentally creating a map of a real magnetic field (we measure and save the different tesla values at the different positions). Then, to see how this field interacts with objects, we want to use an exact representation of this field in the simulation, so that we can see the influence of this exact field on certain objects (for example what force is applied due to the magnetic field). That's why we are looking for a way to import our measured data into Ansys. 

        I did not yet look into your recommended examples, but I will in the next couple of days. Thank you for that.

        Joshua

    • Jim Day
      Ansys Employee
      Interesting. The EM developers wonder how refined your experimental map is. What's the format? The accuracy of the forces will depend on how well you're able to describe the field.
      • Joshua Igl
        Subscriber

        The resolution is still to be determined. For the format it would be nice to know what is recommended or necessary for the input, since we can probably adjust to that. For now it's basically just a matrix with tesla values.

        I'm aware of the dependencies of the accuracy, but in the first place it's important for us to know if - and if yes - how it is possible to use input data.  

        I'm sorry, I did not quite understand what you mean with your last message: "The developers may consider expanding the capability of *EM_EXTERNAL_FIELD pending a more complete understanding of your situation." Could you go more into detail? 

        Thank you very much for your help Jim. Let me know if you need any further information. 

        Joshua

         

    • Jim Day
      Ansys Employee
      The developers may consider expanding the capability of *EM_EXTERNAL_FIELD pending a more complete understanding of your situation.
    • Jim Day
      Ansys Employee
      Currently, we have a feature *EM_EXTERNAL_FIELD (Vol. III of the LS-DYNA User's Manual) that is used to input a magnetic field and then calculate the Eddy currents and the Lorentz force in conductors that are subjected to that field. The magnetic field is input either by (1) a function (*DEFINE_FUNCTION) with spatial variables x,y,z, time t, emdt, pot, curr, and sigma, or or (2) three curves (*DEFINE_CURVE) defining the x,y, and z component of the magnetic field, resp., versus time. Neither (1) nor (2) is a completely general way to input a magnetic field that varies arbitrarily over time and space.
    • Jim Day
      Ansys Employee
      To input a magnetic field that doesn't fit the form of (1) or (2) above, the developers would consider implementing a new option in which a user-defined subroutine provides the midpoint coordinates of each BEM edge and current time value as arguments and which would need to return the corresponding (Bx,By,Bz) values. Do you need such a general capability? If so and you're serious about testing such a feature, the developers will want to contact you directly via your email address on file.
    • Joshua Igl
      Subscriber

      That sounds very interesting. I will need to talk to our project leader, he is currently out of office but will return september 18th.

      Then I think it's also necessary to give you / the developers more detailed information on what we are planning to do, but this is not possible in this forum. 

      In the mean time, feel free to contact me via email, I will consult the team and let you know how we proceed. 

      Thank you, 

      Joshua

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