*HEADING
: SIMPLE CONTACT TEST, 3-D SMALL SLIDING, TYPE=SURFACE TO SURFACE, DEFORMABLE
** C3D5
** Contact Features Tested: 
**	*CONTACT INTERFERENCE w/SHRINK, *FRICTION, 
**      *CHANGE FRICTION (mu=0 and mu=0.3),
**
*NODE
       1,        -0.2,        -0.2,         9.9
       2,         1.2,        -0.2,         9.9
       3,        -0.2,         1.2,         9.9
       4,         1.2,         1.2,         9.9
       9,        -0.2,        -0.2,        11.9
      10,         1.2,        -0.2,        11.9
      11,        -0.2,         1.2,        11.9
      12,         1.2,         1.2,        11.9
      21,          0.,          0.,          8.
      22,          1.,          0.,          8.
      23,          0.,          1.,          8.
      24,          1.,          1.,          8.
      25,          0.,          0.,         10.
      26,          1.,          0.,         10.
      27,          0.,          1.,         10.
      28,          1.,          1.,         10.
**
** Contact node set
**
*NSET,NSET=CNALL,GEN
1,4,1
25,28,1
**
**
*ELEMENT, TYPE=C3D5, ELSET=PROP1
 1, 1, 2,  4, 3, 12
 2, 1, 3, 11, 9, 12
 3, 1, 9, 10, 2, 12
 4, 21,22,24,23, 28
 5, 21,23,27,25, 28
 6, 21,25,26,22, 28
**
** Prop1
**
*SOLID SECTION, ELSET=PROP1, MATERIAL=MAT1
*MATERIAL, NAME=MAT1
*ELASTIC
 30.0E6, 0.0
**
*RESTART, WRITE, FREQUENCY=3
**
** TOP_DISP
**
*BOUNDARY, OP=NEW
       9, 1,,          0.
       9, 2,,          0.
       9, 3,,          0.
      10, 1,,          0.
      10, 2,,          0.
      10, 3,,          0.
      11, 1,,          0.
      11, 2,,          0.
      11, 3,,          0.
      12, 1,,          0.
      12, 2,,          0.
      12, 3,,          0.
**
** Bot_DISP
**
*BOUNDARY, OP=NEW
      21, 1,,          0.
      21, 2,,          0.
      21, 3,,          0.
      22, 1,,          0.
      22, 2,,          0.
      22, 3,,          0.
      23, 1,,          0.
      23, 2,,          0.
      23, 3,,          0.
      24, 1,,          0.
      24, 2,,          0.
      24, 3,,          0.
**
** TOP ELEMENT CONTACT SURFACE
**
*surface,NAME=BSURF
   1, S1
**
** BOTTTOM ELEMENT CONTACT SURFACE
**
*surface,NAME=TSURF
  5, S4
  6, S3
*CONTACT PAIR,INTERACTION=SLIDE,SMALL SLIDING, TYPE=SURFACE TO SURFACE
TSURF, BSURF
*SURFACE INTERACTION,NAME=SLIDE
*FRICTION
0., 
**
** step 1: Shrink fit with *CONTACT INTERFERENCE.
** 	   Establish base state.
**
*STEP ,NLGEOM
*STATIC
0.25,1.
*CONTACT INTERFERENCE, SHRINK
TSURF,BSURF
*ENERGY FILE,FREQ=4
*CONTACT PRINT,SLAVE=TSURF,MASTER=BSURF,NSET=CNALL
*CONTACT FILE,SLAVE=TSURF,MASTER=BSURF,F=4
*EL FILE ,FREQ=4
 S,
 E,
*NODE FILE,FREQ=4
 RF,
*ENERGY PRINT
*EL PRINT ,SUM=NO
 S,
 E,
*NODE PRINT,SUM=NO
 RF,
*END STEP
**
** step 2: slide top cube to the right w/o friction
**
*STEP,PERT
*STATIC
1.0, 1.0
*BOUNDARY
       9, 1,,          0.1
      10, 1,,          0.1
      11, 1,,          0.1
      12, 1,,          0.1
*ENERGY FILE,FREQ=6
*EL FILE ,FREQ=6
 S,
 E,
*NODE FILE,FREQ=6
 U,
 RF,
*CONTACT FILE,SLAVE=TSURF,MASTER=BSURF,F=6
*ENERGY PRINT
*EL PRINT ,SUM=NO
 S,
 E,
*NODE PRINT,SUM=NO
 RF,
*END STEP
**
** step 3: change surface friction
**
*STEP,NLGEOM
*STATIC
1.0,1.0
*CHANGE FRICTION,INTERACTION=SLIDE
*FRICTION
0.3, 
*ENDSTEP
**
** step 4: slide to the left w/ friction
**
*STEP,PERT
*STATIC
1.0 , 1.0
*BOUNDARY
       9, 1,,          -0.1
      10, 1,,          -0.1
      11, 1,,          -0.1
      12, 1,,          -0.1
*ENERGY FILE,FREQ=6
*EL FILE, FREQ=6
S,
E, 
*NODE FILE, FREQ=6
U,
RF, 
*CONTACT FILE,SLAVE=TSURF,MASTER=BSURF, FREQ=6
*CONTACT PRINT,SLAVE=TSURF,MASTER=BSURF, FREQ=6,NSET=CNALL
*PRINT,CONTACT=YES
*ENDSTEP