EM_CONTROL_MAGNET syntax issues

- April 2, 2026 at 9:55 pm
  
  troy.baker
  Subscriber
  
  I recently noticed something I didn't understand with the EM_CONTROL_MAGNET keyword. On page 385 of the keyword manual (https://lsdyna.ansys.com/wp-content/uploads/2025/04/LS-DYNA_Manual_Vol_III_R16.pdf) it mentions there are two inputs, both mcomp to turn on the keyword, and ncycm to set the number of cycles. So it would be written like this:
  *EM_CONTROL_MAGNET
  $# mcomp ncycm
  1 100
  However, when I use lsprepost to make a keyword file and include the EM_CONTROL_MAGNET keyword, there is no ncycm command, only the mcomp, and it is automatically written as:
  *EM_CONTROL_MAGNET
  $# mcomp
  1
  
  Moreover, with the syntax written by LSPP, the simulation will crash stating "forrtl: severe (164): Program Exception - integer divide by zero" after assembling Fem-Bem matricies, and building P mat, Q mat, and W mat through 100 percent. This may be a problem with the syntax, or maybe the rebuilding of magnetic vector of a deforming magnet happens too often and there is a threshold somewhere between NCYCM being undefined and 100 that allows the simulation to complete. If it helps, here is the EM chunk of my .k file
  
  *EM_PERMANENT_MAGNET
  $# id pid mtype north south hc
  1 1 1 2 1 21033
  *EM_CONTROL
  $# emsol numls - dimtype nperio - ncylfem ncylbem
  1 100 0 0 1 1
  *EM_CONTROL_MAGNET
  $# mcomp
  1
  *EM_CONTROL_TIMESTEP
  $# tstype dtcons lcid factor tsmin tsmas rlcsf mecats
  3 0.0 0 1.0 1.0E-4 0.25 25 0
  *EM_CONTROL_COUPLING
  $# thcpl smcpl thlcid smlcid thcplfl smcplfl
  1 2 0 0 0 0
  *EM_SOLVER_FEMBEM_MONOLITHIC
  $# mtype stype abstol reltol maxit
  0 1 1.0E-6 1.0E-4 100
  *EM_MAT_002
  $# mid mtype sigma eosid murel eosmu deatht
  1 4 0.0 0 1.1 0 1.0E28
  *EM_EXTERNAL_FIELD
  $# fieldid ftype fdef lcidx lcidy lcidz
  1 1 1 4 2 4
- April 3, 2026 at 7:42 am
  
  ErKo
  Ansys Employee
  
  Hi
  Some keywords are not always fully implemented and done in LSPP so that could be the case.
  
  Please feel free to add the smallest of parts/meshes/ em example here and users/members can perhaps look at it (just say like a cube with max 20 elements or so).
  
  Also state version used NCPU…etc.
  
  All the best
  
  Erko
  - April 3, 2026 at 9:45 am
    
    troy.baker
    Subscriber
    
    Ciao,
    I did not realize that all keywords were not fully integrated with lspp, I thought that was only an issue with the workbench environment.
    My body is 0.06x0.01x0.005 with mesh a uniform cube sizing 0.001x0.001x0.001 (a mm scale body in SI units). I am running Dyna 2025 R2 V4.13.2 with NCPI set to 1 and using SMP double-precision
    - April 3, 2026 at 10:05 am
      
      ErKo
      Ansys Employee
      
      If you add to LSDYNA Magnets snapping — Welcome to LS-DYNA Examples the below it works fine:
      
      see the help manual for ncycm (second variable below):
      
      *EM_CONTROL_MAGENT
      $# mcomp
      1 1
      Erko
    - April 3, 2026 at 10:55 am
      
      troy.baker
      Subscriber
      
      $# LS-DYNA Keyword file created by LS-PrePost(R) 2025 R2 (v4.13.2) - 10Jun2025
      $# Created on Apr-3-2026 (12:29:59)
      *KEYWORD
      *DEFINE_CURVE_TITLE
      Gravity
      $# lcid sidr sfa sfo offa offo dattyp lcint
      1 0 1.0 1.0 0.0 0.0 0 0
      $# a1 o1
      0.0 0.0
      0.003 3.2
      0.006 6.5
      0.009 9.8
      3.6 9.8
      *DEFINE_CURVE_TITLE
      Field
      $# lcid sidr sfa sfo offa offo dattyp lcint
      2 0 1.0 1.0 0.0 0.0 0 0
      $# a1 o1
      0.0 0.0
      0.1 -0.01
      1.2 -0.03
      1.7 -0.05
      3.6 -0.05
      *DEFINE_CURVE_TITLE
      Zero's
      $# lcid sidr sfa sfo offa offo dattyp lcint
      4 0 1.0 1.0 0.0 0.0 0 0
      $# a1 o1
      0.0 0.0
      3.6 0.0
      *LOAD_BODY_Y
      $# lcid sf lciddr xc yc zc cid
      1 1.0 0 0.0 0.0 0.0 0
      *CONTROL_IMPLICIT_AUTO
      $# iauto iteopt itewin dtmin dtmax dtexp kfail kcycle
      1 10 5 1.0E-8 1.0E-5 0.0 0 0
      *CONTROL_IMPLICIT_GENERAL
      $# imflag dt0 imform nsbs igs cnstn form zero_v
      1 1.0E-5 2 1 2 0 0 0
      *CONTROL_TERMINATION
      $# endtim endcyc dtmin endeng endmas nosol
      3.5 0 0.0 0.0 20.0 0
      *MAT_ELASTIC
      $# mid ro e pr da db not used not used
      1 1600.0 1318200 0.49 0.0 0.0 0 0
      *EM_PERMANENT_MAGNET
      $# id pid mtype north south hc
      1 1 1 2 1 21033
      *EM_CONTROL
      $# emsol numls - dimtype nperio - ncylfem ncylbem
      1 100 0 0 1 1
      $#-------------------------------
      $# This Part Here
      $#-------------------------------
      *EM_CONTROL_MAGNET
      $# mcomp
      1
      $#*EM_CONTROL_MAGNET
      $# mcomp ncycm
      $# 1 100
      $#-------------------------------
      *EM_CONTROL_TIMESTEP
      $# tstype dtcons lcid factor tsmin tsmas rlcsf mecats
      3 0.0 0 1.0 1.0E-4 0.25 25 0
      *EM_CONTROL_COUPLING
      $# thcpl smcpl thlcid smlcid thcplfl smcplfl
      1 2 0 0 0 0
      *EM_SOLVER_FEMBEM_MONOLITHIC
      $# mtype stype abstol reltol maxit
      0 1 1.0E-6 1.0E-4 100
      *EM_MAT_002
      $# mid mtype sigma eosid murel eosmu deatht
      1 4 0.0 0 1.1 0 1.0E28
      *EM_EXTERNAL_FIELD
      $# fieldid ftype fdef lcidx lcidy lcidz
      1 1 1 4 2 4
      *EM_OUTPUT
      $ matS matF solS solF mesh
      2 2 2 2 0
      *EM_DATABASE_PARTDATA
      $ outlv dtout
      1 1.16
      *NODE
      $# nid x y z tc rc
      1 0.0 0.0 0.0 0 0
      2 0.012 0.0 0.0 0 0
      3 0.024 0.0 0.0 0 0
      4 0.036 0.0 0.0 0 0
      5 0.048 0.0 0.0 0 0
      6 0.06 0.0 0.0 0 0
      7 0.0 0.0025 0.0 0 0
      8 0.012 0.0025 0.0 0 0
      9 0.024 0.0025 0.0 0 0
      10 0.036 0.0025 0.0 0 0
      11 0.048 0.0025 0.0 0 0
      12 0.06 0.0025 0.0 0 0
      13 0.0 0.005 0.0 0 0
      14 0.012 0.005 0.0 0 0
      15 0.024 0.005 0.0 0 0
      16 0.036 0.005 0.0 0 0
      17 0.048 0.005 0.0 0 0
      18 0.06 0.005 0.0 0 0
      19 0.0 0.0 0.005 0 0
      20 0.012 0.0 0.005 0 0
      21 0.024 0.0 0.005 0 0
      22 0.036 0.0 0.005 0 0
      23 0.048 0.0 0.005 0 0
      24 0.06 0.0 0.005 0 0
      25 0.0 0.0025 0.005 0 0
      26 0.012 0.0025 0.005 0 0
      27 0.024 0.0025 0.005 0 0
      28 0.036 0.0025 0.005 0 0
      29 0.048 0.0025 0.005 0 0
      30 0.06 0.0025 0.005 0 0
      31 0.0 0.005 0.005 0 0
      32 0.012 0.005 0.005 0 0
      33 0.024 0.005 0.005 0 0
      34 0.036 0.005 0.005 0 0
      35 0.048 0.005 0.005 0 0
      36 0.06 0.005 0.005 0 0
      37 0.0 0.0 0.01 0 0
      38 0.012 0.0 0.01 0 0
      39 0.024 0.0 0.01 0 0
      40 0.036 0.0 0.01 0 0
      41 0.048 0.0 0.01 0 0
      42 0.06 0.0 0.01 0 0
      43 0.0 0.0025 0.01 0 0
      44 0.012 0.0025 0.01 0 0
      45 0.024 0.0025 0.01 0 0
      46 0.036 0.0025 0.01 0 0
      47 0.048 0.0025 0.01 0 0
      48 0.06 0.0025 0.01 0 0
      49 0.0 0.005 0.01 0 0
      50 0.012 0.005 0.01 0 0
      51 0.024 0.005 0.01 0 0
      52 0.036 0.005 0.01 0 0
      53 0.048 0.005 0.01 0 0
      54 0.06 0.005 0.01 0 0
      *PART
      $# title
      beam
      $# pid secid mid eosid hgid grav adpopt tmid
      1 1 1 0 0 0 0 0
      *SECTION_SOLID
      $# secid elform aet - - - cohoff gaskett
      1 1 0 0.0 0.0
      *ELEMENT_SOLID
      $# eid pid n1 n2 n3 n4 n5 n6 n7 n8
      1 1 1 2 8 7 19 20 26 25
      2 1 2 3 9 8 20 21 27 26
      3 1 3 4 10 9 21 22 28 27
      4 1 4 5 11 10 22 23 29 28
      5 1 5 6 12 11 23 24 30 29
      6 1 7 8 14 13 25 26 32 31
      7 1 8 9 15 14 26 27 33 32
      8 1 9 10 16 15 27 28 34 33
      9 1 10 11 17 16 28 29 35 34
      10 1 11 12 18 17 29 30 36 35
      11 1 19 20 26 25 37 38 44 43
      12 1 20 21 27 26 38 39 45 44
      13 1 21 22 28 27 39 40 46 45
      14 1 22 23 29 28 40 41 47 46
      15 1 23 24 30 29 41 42 48 47
      16 1 25 26 32 31 43 44 50 49
      17 1 26 27 33 32 44 45 51 50
      18 1 27 28 34 33 45 46 52 51
      19 1 28 29 35 34 46 47 53 52
      20 1 29 30 36 35 47 48 54 53
      *SET_NODE_LIST_TITLE
      NODESET(SPC) 1
      $# sid da1 da2 da3 da4 solver its -
      1 0.0 0.0 0.0 0.0 1
      $# nid1 nid2 nid3 nid4 nid5 nid6 nid7 nid8
      1 7 13 19 25 31 37 43
      49 0 0 0 0 0 0 0
      *SET_SEGMENT_TITLE
      South
      $# sid da1 da2 da3 da4 solver its -
      1 0.0 0.0 0.0 0.0MECH 0
      $# n1 n2 n3 n4 a1 a2 a3 a4
      7 1 19 25 0.0 0.0 0.0 0.0
      13 7 25 31 0.0 0.0 0.0 0.0
      25 19 37 43 0.0 0.0 0.0 0.0
      31 25 43 49 0.0 0.0 0.0 0.0
      *SET_SEGMENT_TITLE
      North
      $# sid da1 da2 da3 da4 solver its -
      2 0.0 0.0 0.0 0.0MECH 0
      $# n1 n2 n3 n4 a1 a2 a3 a4
      6 12 30 24 0.0 0.0 0.0 0.0
      12 18 36 30 0.0 0.0 0.0 0.0
      24 30 48 42 0.0 0.0 0.0 0.0
      30 36 54 48 0.0 0.0 0.0 0.0
      *BOUNDARY_SPC_SET
      $# nsid cid dofx dofy dofz dofrx dofry dofrz
      1 0 1 1 1 1 1 1
      *END
    - April 3, 2026 at 11:15 am
      
      ErKo
      Ansys Employee
      
      The above example runs fine with:
      
      *EM_CONTROL_MAGENT
      $# mcomp
      1 1
      
      But this keyword is never used I saw so you do not need (magnetization or scalar potential follows the elements so does not need to really be recomputed even if part bends)
      
      Used official LS-Dyna rel 16.1.1-20 (you stated the LSPP rel. that is not important, it is the solver below that is):
      
      | Version : mpp d R16 |
      | Revision: R16.1.1-20-g0c90cad538
      
      (I would not suggest using any other rel. for em analysis – only official rel R16 as the one stated above)
      All the best
      
      Erko
    - April 3, 2026 at 1:12 pm
      
      troy.baker
      Subscriber
      
      My institution has licenses for Ansys 2025r2, and probably wont update that until 2026r2. Currently only 2026r1 is released as far as I know. Is there that much of a gap between the EM keywords between the release 16.1.1 and the release that would come installed with a full 2025 r2 license?
      Solver output files state:
      
      | LS-DYNA, A Program for Nonlinear Dynamic |
      | Analysis of Structures in Three Dimensions |
      | Date : 05/14/2025 Time: 11:18:04 |
      | Version : smp d R14 |
      | Revision: R14.1.1-16-gfadfb49b17
      
      So i believe that is release 14.1, which would be the 2023 version. I previously used the 2023 R2 license and updated it a few months ago, maybe it only updated files related to workbench and not Dyna. Although the LSrun files are stored in Program Files/ANSYSInc/v252 where the rest of the Ansys 2025 version files should be kept instead of v232, where the 2023 version files should be. Is there a specific way to run an update for LS dyna under the license key i have without having to uninstall, clear all files, and reinstall the rest of my Ansys programs?
      
      I ask becasue once using the two argument based EM_CONTROL_MAGNET keyword, I run into error with
      *EM_OUTPUT_FORCES
      $# iout outdt lcoff sf
      1 0.0 0 1.0
      
      where it says the line relating to arguments is incorrect:
      
      *** Error 10246 (KEY+246)
      line contains improperly formatted data
      reading *EM_OUTPUT
      At line# 78 of file
      C:\Users\user\filepath\Testing.k
      --------------------------------------------------------------------------
      1 0.0 0 1.0
      --------------------------------------------------------------------------
      It references EM_OUTPUT but then the commands under the line for EM_OUTPUT_FORCES, so maybe the older release doesn't recognize the output_forces keyword
- April 3, 2026 at 2:01 pm
  
  ErKo
  Ansys Employee
  
  Do not use WB LS-Dyna (not supported only resistive heat solver is) for this and do not use R14.
  
  For EM always use official LS-Dyna rel 16.1.1-20 (you stated the LSPP rel. that is not important, it is the solver below that is):
  
  | Version : mpp d R16 |
  | Revision: R16.1.1-20-g0c90cad538
  
  (I would not suggest using any other rel. for em analysis – only official rel R16 as the one stated above)
  
  You can talk to your Uni and they can download and install R16.
  LSDYNA Download / Install Overview
  See here for credentials
  LS-Dyna License Manger – Network License Registration
  
  All the best – that is it for me – happy easter
  and good luck
  
  Erko

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EM_CONTROL_MAGNET syntax issues

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