*HEADING
 : FINITE SLIDING CONTACT USING MODIFIED 
TETRAHEDRAL ELEMENTS
ZERO FRICTION
*NODE
1, 
7,7.5
*NGEN, NSET=E1
1,7
*NCOPY, OLDSET=E1, NEWSET=E2, SHIFT, CHANGE=20
0., 0., 2.5

*NFILL, NSET=BOT
E1,E2,2,10
*NCOPY, OLDSET=BOT, NEWSET=TOP, SHIFT, CHANGE=200
0.,2.,0.

*NFILL, NSET=BALL
BOT,TOP,2,100
*NODE
501, 0.5, 2.1, 0.25
503, 2.25, 2.1, 0.25
*NGEN, NSET=S1
501,503
*NCOPY, OLDSET=S1, NEWSET=S2, SHIFT, CHANGE=20
0., 0., 2.0

*NFILL, NSET=SLI_BOT
S1,S2,2,10
*NCOPY, OLDSET=SLI_BOT, NEWSET=SLI_TOP, SHIFT, CHANGE=200
0.,2.0,0.

*NFILL, NSET=SALL  
SLI_BOT,SLI_TOP,2,100
*NSET, NSET=BC1
1,11,21,101,111,201,211,221
*NSET, NSET=NALL
BALL, SALL
*NMAP, NSET=NALL, TYPE=RECTANGULAR
0,0,0,.8,.0,.6
.48,.6,-.64
*TRANSFORM, NSET=NALL
.8,.0,.6,.48,.6,-.64
*ELEMENT, TYPE=C3D10M
1, 1,21,3,201, 11,12,2, 101,111,102
2, 3,203,201,223, 103,202,102, 113,213,212
3, 21,201,221,223, 111,211,121, 122,212,222
4, 3,21,23,223, 12,22,13, 113,122,123
5, 3,201,21,223, 102,111,12, 113,212,122
*ELGEN, ELSET=BLOCK
1,3,2,5
2,3,2,5
3,3,2,5
4,3,2,5
5,3,2,5
*ELGEN
1,2,500,500
2,2,500,500
3,2,500,500
4,2,500,500
5,2,500,500
*ELSET, ELSET=SLIDER, GEN
501,505
*ELSET, ELSET=EALL
SLIDER, BLOCK
*SOLID SECTION, ELSET=EALL, MATERIAL=MAT
*MATERIAL, NAME=MAT
*ELASTIC
30.0E6, 0.3
*ELSET, ELSET=BTOP,GEN
2,12,5
3,13,5
*ELSET, ELSET=SBOT
501,504
*surface, NAME=SL1
SBOT, S1
*surface, NAME=MA1
BTOP, S3
*CONTACT PAIR, INTERACTION=INT
SL1, MA1
*SURFACE INTERACTION, NAME=INT
*BOUNDARY
BC1,1
BOT,2,3
SLI_TOP,3
*STEP, NLGEOM, INC=100, UNSYMM=YES
 FIRST COMPRESS
*STATIC,DIRECT
0.67,1.0
*CONTROLS, PARAMETER=FIELD
1.0E-6, 
*BOUNDARY
SLI_TOP,1
SLI_TOP,2,2,-.15
*EL PRINT, F=0
*NODE PRINT, F=0
*EL FILE,FREQ=5
S,E
*NODE FILE,FREQ=5
U,RF
*CONTACT FILE, MASTER=MA1
CSTRESS,CDISP
CAREA, 
CFN,CFS
CMN,CMS
CFT,CMT
XN,XS,XT
*END STEP
*STEP, NLGEOM, INC=100, UNSYMM=YES
 SLIDE ACROSS TOP - ZERO FRICTION
*STATIC
0.1,1.0
*BOUNDARY
SLI_TOP,2,2,-.15
SLI_TOP,1,1,4.
*END STEP