*HEADING 
:  CONCENTRIC RINGS WITH INITIAL OVERCLOSURE [CPS4]
*NODE
999,0.,0.
1,3.5,0.0
17,3.5,0.0
18,4.7,0.0
34,4.7,0.0
35,4.6,0.0
51,4.6,0.0
52,6.1,0.0
68,6.1,0.0
*NGEN,LINE=C,NSET=RAD_1
1,17,1,999,,,,0.0,0.0,1.0
*NGEN,LINE=C,NSET=RAD_2
18,34,1,999,,,,0.0,0.0,1.0
*NGEN,LINE=C,NSET=RAD_3
35,51,1,999,,,,0.0,0.0,1.0
*NGEN,LINE=C,NSET=RAD_4
52,68,1,999,,,,0.0,0.0,1.0
*NSET,NSET=INNER,GEN
1,17,1
*ELEMENT,TYPE=CPS4
1,1,18,19,2
16,16,33,18,1
17,35,52,53,36
32,50,67,52,35
*ELGEN,ELSET=INELE
1,15,1,1,
*ELGEN,ELSET=OUTELE
17,15,1,1
*ELSET,ELSET=INELE,GEN
1,16,1
*ELSET,ELSET=OUTELE,GEN
17,32,1
*SOLID SECTION, ELSET=INELE, MATERIAL=MAT_1
1.0, 
*SOLID SECTION, ELSET=OUTELE, MATERIAL=STEEL
1.0, 
*MATERIAL, NAME=STEEL
*DENSITY
8.0100E-06, 
*ELASTIC, TYPE=ISO
206800.,.32
*MATERIAL, NAME=MAT_1
*DENSITY
8.0100E-06, 
*ELASTIC,TYPE=ISOTROPIC
206800.,.32
*surface,NAME=IN_SURF
INELE,S2
*surface,NAME=OUT_SURF
OUTELE,S4
*CONTACT PAIR,INTERACTION=FRIC,SMOOTH=0.05
IN_SURF,OUT_SURF
*SURFACE INTERACTION,NAME=FRIC
1.0, 
*BOUNDARY
INNER,1,2
52,2,2
60,2,2
*STEP
 PRELOAD
*STATIC
0.5,1.0
*CONTACT INTERFERENCE,SHRINK
IN_SURF,OUT_SURF
*CONTACT FILE
*EL FILE
SP, 
S, 
SINV, 
*NODE FILE
RF, 
U, 
*END STEP