*HEADING
**
** Contact between aligned blocks in 2D.
**
*NODE,NSET=NB1
1, 0.,0.
2, 1.,0.
3, 2.,0.
4, 3.,0.
5, 4.,0.
11,0.,1.
12,1.,1.
13,2.,1.
14,3.,1.
15,4.,1.
*ELEMENT,ELSET=EB1,TYPE=CPS4R
1,1,2,12,11
*ELGEN,ELSET=EB1
1,4,1,1
*NSET,NSET=FIX_N
1,2,3,4,5
*BOUNDARY
FIX_N,2,2
1,1,2
**
*NODE,NSET=NB2
101,0.,1.1
102,1.,1.1
103,2.,1.1
104,3.,1.1
105,4.,1.1
111,0.,2.1
112,1.,2.1
113,2.,2.1
114,3.,2.1
115,4.,2.1
*ELEMENT,ELSET=EB2,TYPE=CPS4R
101,101,102,112,111
*ELGEN,ELSET=EB2
101,4,1,1
*NSET,NSET=LOAD_N
111,112,113,114,115
**
*ELSET,ELSET=EALL
EB1,EB2
**
*SOLID SECTION,ELSET=EALL,MATERIAL=MAT1
*MATERIAL,NAME=MAT1
*ELASTIC
1.E6,0.2
*DENSITY
1., 
*SURFACE,TYPE=ELEMENT,NAME=SB1
EB1,
*SURFACE,TYPE=ELEMENT,NAME=SB2
EB2,
**
*AMPLITUDE,NAME=SMOOTH1,DEFINITION=SMOOTH STEP
0.,0.,1.e-3,0.,5.e-3,1.
*AMPLITUDE,NAME=SMOOTH2,DEFINITION=SMOOTH STEP
0.,0.,1.e-3,1.,5.e-3,1.
**
*NSET, NSET=QA_TEST_ALLNODES
NB1, NB2
**
*STEP
*DYNAMIC,EXPLICIT,DIRECT
2.5e-4,5.e-3
**
*BOUNDARY,AMPLITUDE=SMOOTH1
LOAD_N,1,1,0.001
*BOUNDARY,AMPLITUDE=SMOOTH2
LOAD_N,2,2,-0.0001
**
*CONTACT PAIR,INTERACTION=USERINTER, MECHANICAL CONSTRAINT=PENALTY
SB1,SB2
*SURFACE INTERACTION,PADTHICKNESS=0.1,NAME=USERINTER,USER,DEPVAR=3,PROPERTIES=7

0.01,1.E5,0.2,1.E3,1.E4,0.1,0.
**
*FILE OUTPUT,NUM=1
*NODE FILE
U,
**
*OUTPUT, FIELD, NUMBER INTERVAL=1
*NODE OUTPUT, NSET=QA_TEST_ALLNODES
u,
*OUTPUT,FIELD,VARIABLE=PRESELECT
*OUTPUT,HISTORY,VARIABLE=PRESELECT,TIMEINT=0.005
*END STEP