*HEADING
 : *MODEL CHANGE verification for 2D small-sliding contact
*PREPRINT,MODEL=YES
*NODE
1,0.0,0.0
7,7.5,0.0
11,,2.
17,7.5,2.0
101,0.5,2.1
103,2.25,2.1
111,0.5,4.1
113,2.25,4.1
21,0.0,0.0
27,7.5,0.0
31,,2.
37,7.5,2.0
121,0.5,2.1
123,2.25,2.1
131,0.5,4.1
133,2.25,4.1
*NGEN,NSET=BASE
1,7,2
*NGEN,NSET=BASER
21,27,2
*NGEN,NSET=TOP
111,113,2
*NGEN,NSET=TOPR
131,133,2
*NGEN
11,17,2
101,103
31,37,2
121,123
*ELEMENT,TYPE=CPE4,ELSET=STEEL
1,1,3,13,11
11,101,103,113,111
21,21,23,33,31
31,121,123,133,131
*ELGEN,ELSET=STEEL
1,3,2
21,3,2
*ELSET,ELSET=EBOT,GENERATE
1,3,1
*ELSET,ELSET=EBOTR,GENERATE
21,23,1
*ELSET,ELSET=ETOP
11, 
*ELSET,ELSET=ETOPR
31, 
*ELSET,ELSET=TEST
1,2,3,11
*ELSET,ELSET=REFER
21,22,23,31
*surface,NAME=A_SURFACE
ETOP,S1
*surface,NAME=B_SURFACE
EBOT,S3
*CONTACT PAIR,INTERACTION=ROUGH,SMOOTH=0.1
A_SURFACE,B_SURFACE
*surface,NAME=A_SURFR
ETOPR,S1
*surface,NAME=B_SURFR
EBOTR,S3
*CONTACT PAIR,INTERACTION=ROUGH,SMOOTH=0.1
A_SURFR,B_SURFR
*SURFACE INTERACTION,NAME=ROUGH
*FRICTION
0.2, 
*SOLID SECTION,ELSET=STEEL,MATERIAL=STEEL
*MATERIAL,NAME=STEEL
*ELASTIC
 30.E6,0.3
**********
**
**
**
*STEP,UNSYMM=YES
  1 CONTACT -- Push top element down
*STATIC
 0.67,1.
*CONTROLS,PARAMETERS=FIELD
1.0E-6, 
*BOUNDARY
BASE,2
BASER,2
1,1
11,1
21,1
31,1
TOP,2,,-.15
TOP,1
TOPR,2,,-.15
TOPR,1
*PRINT,CONTACT=YES
*EL PRINT,FREQ=50
S,E
*NODE PRINT,FREQ=50
U,RF
*OUTPUT,FIELD,FREQ=50
*ELEMENT OUTPUT
S,E
*NODE OUTPUT
U,RF
*CONTACT OUTPUT, SECONDARY=A_SURFACE
CSTRESS,CDISP
*CONTACT OUTPUT, SECONDARY=A_SURFR
CSTRESS,CDISP
*CONTACT PRINT, SECONDARY=A_SURFACE, FREQ=50
CSTRESS,CDISP
carea,
CFN,CFS
CMN,CMS
CFT,CMT
XN,XS,XT
*CONTACT PRINT, SECONDARY=A_SURFR, FREQ=50
CSTRESS,CDISP
carea,
CFN,CFS
CMN,CMS
CFT,CMT
XN,XS,XT
*END STEP
**
**
*STEP,UNSYMM=YES
  2 Slide Top Across
*STATIC
 1.,10.,1.
*BOUNDARY,OP=NEW
 BASE,2
BASER,2
1,1
11,1
21,1
31,1
TOP,2,,-.15
TOP,1,,4.
TOPR,2,,-.15
TOPR,1,,4.
*END STEP
**
**
**
*STEP, UNSYMM=YES
 3 Remove contact condition
*STATIC
1,10,1
*model change,remove,type=contact pair
 A_SURFACE,B_SURFACE
*BOUNDARY,OP=NEW
 BASE,2
BASER,2
1,1
11,1
21,1
31,1
TOP,2,,-.15
TOP,1,,4.
TOPR,2,,-.099999999
TOPR,1,,4.
*END STEP
**
**
*STEP, UNSYMM=YES,INC=100
 6 reactivate contact gradually with contact interference
 The overclosure is not greater than 0.05
*STATIC
.1,10,.1
*model change,add,type=contact pair
 A_SURFACE,B_SURFACE
*contact interfer,type=contact pair
 A_SURFACE, B_SURFACE, 0.05
*BOUNDARY,OP=NEW
 BASE,2
BASER,2
1,1
11,1
21,1
31,1
TOP,2,,-.15
TOP,1,,4.
TOPR,2,,-.15
TOPR,1,,4.
*END STEP
**