A railgun consists of two parallel metal rails connected to an electric power supply. The projectile completes the circuit. The current flowing through the rails and projectile generates a magnetic field which in turn generates a Lorentz force propelling the projectile out of the barrel at a very high speed. This problem serves as an example to illustrate the EM contact. Current is allowed to flow through conductors by ‘stitching the BEM meshes of the various parts together. As such, it is highly recommended to re-compute the BEM matrix often to ensure stability.
Current Density fringes
*CONTROL_TERMINATION *CONTROL_TIMESTEP *DATABASE_BINARY_D3PLOT *DEFINE_CURVE_FUNCTION *DEFINE_CURVE_TITLE *EM_DATABASE_GLOBALENERGY *EM_CIRCUIT *EM_CIRCUIT_ROGO *EM_CONTROL *EM_CONTROL_CONTACT *EM_MAT_001 *EM_OUTPUT *EM_SOLVER_FEM *EM_SOLVER_BEM *EM_SOLVER_BEMMAT *END *KEYWORD *MAT_ELASTIC *MAT_RIGID *PARAMETER *PART *SECTION_SOLID *TITLE
$-----------------------------------------------------------------------------
$
$ 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 Railgun example
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ EM CONTROL $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*EM_CONTROL
$--------1---------2---------3---------4---------5---------6---------7---------8
$ emsol
1
*EM_CONTROL_CONTACT
$--------1---------2---------3---------4---------5---------6---------7---------8
$ EMcont
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
$--------1---------2---------3---------4---------5---------6---------7---------8
$ circid circtype lcid
1 1 4
$ ssidCurr ssidVltin ssidVltOt partID
4 1 2
$---+----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 eosId skinDepth
1 2 &em_cond
*EM_MAT_001
2 2 &em_cond
*EM_MAT_001
3 2 &em_cond
$---+----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_GLOBALENERGY
$# outlv
1
*END
