Linear

The center node of a plate moves in the normal direction. Two other nodes that are neighbors to the center node are constrained such that their displacement in the normal direction is identical.

*CONSTRAINED_LINEAR
Linearly Constrained Plate
LS-DYNA Manual Section: *CONSTRAINED_LINEAR

Additional Sections:
BOUNDARY_PRESCRIBED_MOTION_NODE
DEFINE_CURVE

Example: Linearly Constrained Plate

Filename: constrained.linear.plate.k

Description:
The center node of a plate moves in the normal direction. Two other nodes that
are neighbors to the center node are constrained such that their displacement
in the normal direction is identical.

Model:
The plate is made of an elastic material measuring 40 * 4 0* 2 mm3 and contains
64 Hughes-Liu shell elements. The center node displacement increases linearly.
At the termination time, 0.0005 seconds, the displacement is 15 mm. The degree
of freedom in the z-direction for the two nodes is identical.

Input:
A load curve defines the ma gnitude of the prescribed displacement of the
center node (*BOUNDARY_PRESCRIBED_MOTION_NODE, *DE FINE_CURVE). A linear
constraint card defines the coupling of the displacement in the z -direction
between the two nodes (*CONSTRA INED_LINEAR). Two equal coefficients with
opposite signs control the displacement.

Reference:
Schweizerhof, K. and Weimar, K.

*BOUNDARY_PRESCRIBED_MOTION_NODE
*CONSTRAINED_LINEAR
*CONTROL_CONTACT
*CONTROL_HOURGLASS
*CONTROL_SHELL
*CONTROL_TERMINATION
*DATABASE_BINARY_D3PLOT
*DATABASE_BINARY_D3THDT
*DATABASE_EXTENT_BINARY
*DATABASE_HISTORY_NODE
*DATABASE_NODOUT
*DEFINE_CURVE
*ELEMENT_SHELL
*END
*KEYWORD
*MAT_ELASTIC
*NODE
*PART
*SECTION_SHELL
*TITLE

  *KEYWORD
  *TITLE
  Linear Constraint Equations
  $
  $  LSTC Example
  $
  $  Last Modified: September 3, 1997
  $
  $   Units: mm, s
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Control Ouput
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
  $
  *CONTROL_TERMINATION
  $   endtim    endcyc     dtmin    endneg    endmas
      0.0005
  $
  *CONTROL_CONTACT
  $   slsfac    rwpnal    islchk    shlthk    penopt    thkchg     orien
         0.1                   2
  $
  $   usrstr    usrfac     nsbcs    interm    xpenen
  
  $
  *CONTROL_HOURGLASS
  $      ihq        qh
           4
  $
  *CONTROL_SHELL
  $   wrpang    itrist     irnxx    istupd    theory       bwc     miter
                                                   1
  $
  $
  *DATABASE_BINARY_D3PLOT
  $       dt      lcdt
     0.00002
  $
  *DATABASE_BINARY_D3THDT
  $       dt      lcdt
     0.00001
  $
  *DATABASE_EXTENT_BINARY
  $    neiph     neips    maxint    strflg    sigflg    epsflg    rltflg    engflg
                                         1
  $
  $   cmpflg    ieverp    beamip
  
  $
  $
  *DATABASE_HISTORY_NODE
  $      id1       id2       id3       id4       id5       id6       id7       id8
  $...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
          40        41        42
  $      
  *DATABASE_NODOUT
  $       dt
     0.00001
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Constraints and Boundary Conditions
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8
  $
  $$$$  nodes 40 and 42 are constrained to have identical z-direction motion
  $
  *CONSTRAINED_LINEAR
  $      num
           2
  $
  $      nid      dofx      dofy      dofz    dofrx      dofry     dofrz      coef
          40                             1                                    1.00
          42                             1                                   -1.00
  $
  $
  $$$$  node 41 is displaced in the z-direction according to load curve 1
  $
  *BOUNDARY_PRESCRIBED_MOTION_NODE
  $      nid       dof       vad      lcid        sf       vid
          41         3         2         1       1.0
  $
  *DEFINE_CURVE
  $     lcid      sidr      scla      sclo      offa      offo
           1
  $
  $           abscissa            ordinate
                   0.0                 0.0
                0.0005               -15.0
                0.0015               -15.1
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  $$$$  Define Parts and Materials
  $
  $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
  $
  *PART
  Impacted Material 
  $      pid       sid       mid     eosid      hgid    adpopt
           1         1         1         0         0         0
  $
  $
  $$$$$$  Materials
  $
  *MAT_ELASTIC
  $      mid        ro         e        pr        da        db         k
           1   2.00e-8  100000.0     0.300
  $
  $
  $$$$$$  Sections
  $
  *SECTION_SHELL
  $      sid    elform      shrf       nip     propt   qr/irid     icomp
           1         6   0.83333       2.0       3.0
  $
  $       t1        t2        t3        t4      nloc
         2.0       2.0       2.0       2.0
  $
  $
  *END