*HEADING
: *CONTACT INTERFERENCE,TYPE=ELEMENT  [GAPSPHER]
*NODE,NSET=BASE
1,
2,1.,
3,1.,1.2,
4,,1.2
11,0.,1.
12,1.,1.
13,1.,3.
14,0.,3.
*NCOPY,OLDSET=BASE,NEWSET=COPY,SHIFT,CHANGE NUMBER=100
0.,0.,1.

*ELEMENT,TYPE=C3D8,ELSET=BOT
1,1,2,3,4,101,102,103,104
*ELEMENT,TYPE=C3D8,ELSET=TOP
11,11,12,13,14,111,112,113,114
*SOLID SECTION,ELSET=TOP,MATERIAL=MAT
*SOLID SECTION,ELSET=BOT,MATERIAL=MAT
*MATERIAL,NAME=MAT
*ELASTIC
1.E5,0.
*BOUNDARY
1,1,2
2,1,2
13,1,2
14,1,2
101,1,2
102,1,2
113,1,2
114,1,2
BASE,3,3
COPY,3,3
*ELEMENT,TYPE=GAPSPHER,ELSET=INTER
21,4,11
22,3,12
23,104,111
24,103,112
*GAP,ELSET=INTER
0.00001,
*STEP,INC=20,NLGEOM
*STATIC
0.2,1.,0.2,0.2
*CONTACT INTERFERENCE,TYPE=ELEMENT,OP=NEW
INTER,0.2
*OUTPUT,FIELD
*ELEMENT OUTPUT
S,
*OUTPUT,FIELD
*NODE OUTPUT
U,
*PRINT,CONTACT=YES
*ENDSTEP