Electromagnetic forming problem — Welcome to LS-DYNA Examples

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This LS-DYNA simulation shows a simple Electromagnetic forming example using the EM solver. A R,L,C circuit is defined in the coil which produces induced currents in the workpiece. This in turn generates Lorentz forces which cause the plate to move. Local heating is also produced and handled by the thermal solver.

Description

This LS-DYNA simulation shows a simple Electromagnetic forming example using the EM solver. A R,L,C circuit is defined in the coil which produces induced currents in the workpiece. This in turn generates Lorentz forces which cause the plate to move. Local heating is also produced and handled by the thermal solver. An EM EOS couples back the temperature to the Electromagnetic solver by making the electromagnetic conductivity temperature dependent. The FEM and BEM matrices are recalculated every 20 timesteps in order to save calculation times. Coupling between EM and the thermal and mechanical solvers is automatic (no extra keyword mandatory).

Animated Result

EM current density fringes

ezgif.comvideotogif.gif

Keywords

*CONTROL_CONTACT                                                                
*CONTROL_SOLUTION
*CONTACT_SURFACE_TO_SURFACE
*CONTROL_TERMINATION
*CONTROL_TIMESTEP
*CONTROL_THERMAL_SOLVER
*CONTROL_THERMAL_TIMESTEP
*DATABASE_BINARY_D3PLOT
*DEFINE_CURVE_TITLE
*EM_BOUNDARY
*EM_CIRCUIT
*EM_CIRCUIT_ROGO
*EM_CONTROL
*EM_CONTROL_TIMESTEP
*EM_DATABASE_CIRCUIT0D
*EM_EOS_MEADON
*EM_EOS_TABULATED1
*EM_MAT_001
*EM_OUTPUT
*EM_SOLVER_FEM
*EM_SOLVER_BEM
*EM_SOLVER_BEMMAT
*END
*HOURGLASS
*INITIAL_TEMPERATURE_SET
*KEYWORD
*MAT_024
*MAT_RIGID
*MAT_THERMAL_ISOTROPIC
*PARAMETER
*PART
*SECTION_SHELL
*SECTION_SOLID
*TITLE

Reduced Input

$-----------------------------------------------------------------------------
$
$ Example provided by Iñaki (LSTC)
$
$ E-Mail: info@dynamore.de
$ Web: http://www.dynamore.de
$
$ Copyright, 2015 DYNAmore GmbH
$ Copying for non-commercial usage allowed if
$ copy bears this notice completely.
$
$X------------------------------------------------------------------------------
$X
$X 1. Run file as is.
$X    Requires LS-DYNA MPP R8.0.0 (or higher) with double precision 
$X
$X------------------------------------------------------------------------------
$# UNITS: (g/mm/s) 
$X------------------------------------------------------------------------------
$X
*KEYWORD
*TITLE
EM Electromagnetic forming problem
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                             EM CONTROL                                       $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*EM_CONTROL
$    emsol        
         1         
*EM_CONTROL_TIMESTEP
$#  tstype    dtcons      lcid                            
         1    &em_dt
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                             EM CIRCUIT                                       $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*EM_CIRCUIT
$   circid  circtype      lcid         R         L         C        V0
         1         3             &em_res   &em_ind   &em_cap    &em_v0
$ ssidCurr ssidVltin ssidVltOt    partID
         4         1         2
*EM_CIRCUIT_ROGO
$#   rogid     setid   settype    curtyp
         4         4         1         1   
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                             EM BOUNDARY                                      $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ remove rear and sides of the plate from the boundary mesh
$ this is optional and is used to speed up the run
*EM_BOUNDARY
$     ssid     btype  
         6         9
*EM_BOUNDARY
$     ssid     btype  
         8         9
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                             EM MAT and EOS                                   $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*EM_MAT_001
$   em_mid     mtype     sigma       eos              
         1         2  &em_cond          
*EM_MAT_001
$   em_mid     mtype     sigma       eos              
         2         1     
*EM_MAT_001            
$   em_mid     mtype     sigma       eos              
         3         4  &em_cond         1  
*EM_EOS_TABULATED1
$#   eosid      lcid
         1        43
*EM_EOS_MEADON
$#   eosid        c1        c2        c3    temuni        v0     gamma     expon
         2  -5.35e-5     0.233     1.210         1         0         0        -0
$# lgtunit   timunit    adjust
      1e-3         1         1
*EM_EOS_MEADON
$#   eosid        c1        c2        c3    temuni        v0     gamma     expon
         3  -4.12e-5     0.133     1.145         1         0         0        -0
$# lgtunit   timunit    adjust
      1e-3         1         1
*DEFINE_CURVE_TITLE
Conductivity function of temperature
$#    lcid      sidr       sfa       sfo      offa      offo    dattyp
        43
$#                a1                  o1
                 0.0                 25.
                25.0                 25.
               200.0                 2.5
               500.0                 2.5
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                             EM SOLVER                                        $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*EM_SOLVER_BEMMAT
$#   matid                                                                reltol
         1                                                                  1e-6 
*EM_SOLVER_BEMMAT
$#   matid                                                                reltol
         2                                                                  1e-6      
*EM_SOLVER_BEM
$#  reltol     maxit     stype    precon    uselas  ncyclbem
      1e-6      1000         2         2         1&em_bemmtx
*EM_SOLVER_FEM
$#  reltol     maxit     stype    precon    uselas  ncyclbem
      1e-3      1000         1         1         1&em_femmtx
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                             EM OUTPUT                                        $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 
*EM_OUTPUT
$     matS      matF      solS      solF      mesh
         2         2         2         2         0   
*EM_DATABASE_CIRCUIT0D
$#   outlv
         1       
*END

Figures

Cylinder Flow

Download

EM_example_emforming.zip

Using conductive shells (less accurate in cases with high EM diffusion) :

EM_example_emformingshell.zip