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’.