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A rod of steel is forged between two dies. The billet upset problem is a measure of friction under forming conditions.

Introduction

*CONTROL_TIMESTEP
Billet Upset
LS-DYNA Manual Section: *CONTROL_TIMESTEP

Example: Billet Upset

Filename: control_timestep.billet-forge.k

Description:
A rod of steel is forged between two dies. The billet upset problem is a
measure of friction under forming conditions.

Model:
The billet material is isotropic elastic-plastic, and the model has
1 * 8 symmetry. The billet measures 2.25 inches in height and 1.26 inches in
radius. The die compresses the billet 1.60 inches. The relationship between
the shear friction and the normal pressure is bilinear.

Input:
The mass scaling time step size is set to 12 microseconds (*CONTRO L_TIMESTEP).
The billet nodes contact the die surfaces (*CONTACT_NODES_TO_SURFACE).
The Coulomb frictional constant is 0.10 and the constant shear is 2,055 psi.
A half sine wave defines the velocity of the die (*BOUNDARY_PRESCRIBED_MOTION).

Results:
The results show that effective plastic strains with and without time-step
control are the same. CPU savings is approximately 33% on the cray J90 using
1 cpu.

Reference:
Avitzur, B., Lee, C. H. and Altan, T.

Keywords

*BOUNDARY_PRESCRIBED_MOTION_RIGID
*CONTACT_NODES_TO_SURFACE
*CONTROL_ENERGY
*CONTROL_OUTPUT
*CONTROL_TERMINATION
*CONTROL_TIMESTEP
*DATABASE_BINARY_D3PLOT
*DATABASE_BINARY_D3THDT
*DATABASE_EXTENT_BINARY
*DATABASE_GLSTAT
*DATABASE_MATSUM
*DATABASE_RBDOUT
*DATABASE_RCFORC
*DEFINE_CURVE
*ELEMENT_SHELL
*ELEMENT_SOLID
*END
*KEYWORD
*MAT_PIECEWISE_LINEAR_PLASTICITY
*MAT_RIGID
*NODE
*PART
*SECTION_SHELL
*SECTION_SOLID
*TITLE

Reduced Input

  *KEYWORD
  *TITLE
  BILLET UPSET
  $
  $  LSTC Example
  $
  $  Last Modified: September 16, 1997
  $
  $  Units: lbf-s2/in, in, s, lbf, psi, lbf-in
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Control Ouput
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  *CONTROL_TERMINATION
  $   endtim    endcyc     dtmin    endneg    endmas
      0.0015
  $
  *CONTROL_TIMESTEP
  $   dtinit      scft      isdo    tslimt      dtms      lctm     erode     ms1st
                                          -1.200E-07
  $
  *CONTROL_ENERGY
  $     hgen      rwen    slnten     rylen
           2         2
  $
  *CONTROL_OUTPUT
  $    npopt    neecho    nrefup    iaccop     opifs    ipnint    ikedit
           1         3
  $
  $
  *DATABASE_BINARY_D3PLOT
  $       dt      lcdt
      0.0001
  $
  *DATABASE_EXTENT_BINARY
  $    neiph     neips    maxint    strflg    sigflg    epsflg    rltflg    engflg
  
  $   cmpflg    ieverp    beamip
                     1
  $
  *DATABASE_BINARY_D3THDT
  $       dt      lcdt
      999999
  $
  *DATABASE_GLSTAT
  $       dt
     0.00001
  $
  *DATABASE_MATSUM
  $       dt
     0.00001
  $
  *DATABASE_RBDOUT
  $       dt
     0.00001
  $
  *DATABASE_RCFORC
  $       dt
     0.00001
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Loading - PRESCRIBED_MOTION_RIGID
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  *BOUNDARY_PRESCRIBED_MOTION_RIGID
  $      mid       dof       vad      lcid        sf       vid
           2         3         0         1 1.000E+00
  $
  *DEFINE_CURVE
  $     lcid      sidr      scla      sclo      offa      offo
           1
  $           abscissa            ordinate
             0.000E+00           0.000E+00
             5.000E-05          -4.931E+00
             1.000E-04          -1.960E+01
             1.500E-04          -4.365E+01
             2.000E-04          -7.649E+01
             2.500E-04          -1.173E+02
             3.000E-04          -1.651E+02
             3.500E-04          -2.187E+02
             4.000E-04          -2.767E+02
             4.500E-04          -3.378E+02
             5.000E-04          -4.005E+02
             5.500E-04          -4.632E+02
             6.000E-04          -5.243E+02
             6.500E-04          -5.823E+02
             7.000E-04          -6.359E+02
             7.500E-04          -6.837E+02
             8.000E-04          -7.245E+02
             8.500E-04          -7.573E+02
             9.000E-04          -7.814E+02
             9.500E-04          -7.961E+02
             1.000E-03          -8.010E+02
             1.050E-03          -7.961E+02
             1.100E-03          -7.814E+02
             1.150E-03          -7.573E+02
             1.200E-03          -7.245E+02
             1.250E-03          -6.837E+02
             1.300E-03          -6.359E+02
             1.350E-03          -5.823E+02
             1.400E-03          -5.243E+02
             1.450E-03          -4.632E+02
             1.500E-03          -4.005E+02
             1.550E-03          -3.378E+02
             1.600E-03          -2.767E+02
             1.650E-03          -2.187E+02
             1.700E-03          -1.651E+02
             1.750E-03          -1.173E+02
             1.800E-03          -7.649E+01
             1.850E-03          -4.365E+01
             1.900E-03          -1.960E+01
             1.950E-03          -4.931E+00
             2.000E-03           0.000E+00
             2.200E-03           0.000E+00
  $
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Define Contacts
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
  $
  *CONTACT_NODES_TO_SURFACE
  $     ssid      msid     sstyp     mstyp    sboxid    mboxid       spr       mpr
           1         2         3         3
  $       fs        fd        dc        vc       vdc    penchk        bt        dt
         0.1       0.1           2.055E+03
  $      sfs       sfm       sst       mst      sfst      sfmt       fsf       vsf
  
  $ 
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Define Parts and Materials
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$ Part    1    solid: Billet - Aluminum
  $
  $$$ Part    2    shell: Press - Aluminum - rigid
  $
  *PART
  $      pid       sid       mid     eosid      hgid    adpopt
  Billet - Aluminum
           1         1         1
  Press - Aluminum
           2         2         2
  $
  $$$$  materials
  $
  *MAT_PIECEWISE_LINEAR_PLASTICITY
  $      mid        ro         e        pr      sigy      etan      eppf      tdel
           1   2.50e-4  10.00e+6      0.33  
  $        c         p      lcss      lcsr
  
  $
  $     eps1      eps2      eps3      eps4      eps5      eps6      eps7      eps8
   0.000E+00 5.000E-03 1.000E-02 5.000E-02 1.000E-01 2.000E-01 7.000E-01 4.000E+00
  $
  $      es1       es2       es3       es4       es5       es6       es7       es8
   4.785E+03 6.505E+03 7.423E+03 1.063E+04 1.254E+04 1.482E+04 2.010E+04 3.081E+04
  $
  $
  *MAT_RIGID
  $      mid        ro         e        pr         n    couple         m     alias
           2   2.50e-4  10.00e+6      0.33
  $      cmo      con1      con2
        -1.0       0.0    110111
  $   lco/a1        a2        a3        v1        v2        v3
         0.0
  $
  $$$$  sections
  $
  *SECTION_SOLID
  $      sid    elform
           1         0
  $
  *SECTION_SHELL
  $      sid    elform      shrf       nip     propt   qr/irid     icomp
           2
  $       t1        t2        t3        t4      nloc
   1.000E-02 1.000E-02 1.000E-02 1.000E-02
  $
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Define Nodes and Elements
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Many nodes have boundary conditions in order to simulate symmetry.
  $
  $
  *END

Figures

image01.gif

image02.gif

Animated Result

Result

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