*HEADING
: SIMPLE CONTACT TEST, 3-D SMALL SLIDING, DEFORMABLE, C3D8H
** Contact Features Tested: 
**	*CONTACT INTERFERENCE w/SHRINK, *FRICTION, 
**      *CHANGE FRICTION (mu=0 and mu=0.3),
*RESTART,WRITE, FREQ=4
*NODE,NSET=BOTTOM
1,0.,0.,8.
3,1.,0.,8.
9,1.,1.,8.
7,0.,1.,8.
*NODE,NSET=BSLIDE
21,0.,0.,10.
23,1.,0.,10.
27,0.,1.,10.
29,1.,1.,10.
*NODE,NSET=TSLID
101,-0.2,-0.2,9.9
103,1.2,-0.2,9.9
107,-0.2,1.2,9.9
109,1.2,1.2,9.9
*NODE,NSET=TOP
121,-0.2,-0.2,11.9
123,1.2,-0.2,11.9
127,-0.2,1.2,11.9
129,1.2,1.2,11.9
*ELEMENT,TYPE=C3D8H,ELSET=SOLID
1,1,3,9,7,21,23,29,27
3,101,103,109,107,121,123,129,127
*ELSET,ELSET=ETOP
3, 
*ELSET,ELSET=EBOT
1, 
*surface, NAME=TSURF
EBOT,S2
*surface,NAME=BSURF
ETOP,S1
*CONTACT PAIR,INTERACTION=SLIDE,SMALL SLIDING
TSURF,BSURF
*SURFACE INTERACTION,NAME=SLIDE
*FRICTION
0., 
*SOLID SECTION,ELSET=SOLID,MATERIAL=SOLMAT
*MATERIAL,NAME=SOLMAT
*ELASTIC
30.E6,.0
*BOUNDARY
TOP,1,3
BOTTOM,1,3
**
** 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
*CONTACT FILE,SLAVE=TSURF,MASTER=BSURF,F=4
*EL FILE ,FREQ=4
 S,
 E,
*NODE FILE,FREQ=4
 U,
 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
*BOUNDARY
TOP,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
*BOUNDARY
TOP,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
*PRINT,CONTACT=YES
*ENDSTEP