*HEADING
: FINITE SLIDING CONTACT
VERIFICATION FOR FRICTION CHANGE
*AMPLITUDE,NAME=CONSTA
0,0.048,1,0.048
*AMPLITUDE,NAME=CONSTB
0,0.060,1,0.060
*AMPLITUDE,NAME=CONSTC
0,-0.064,1,-0.064
*NODE
*NGEN, NSET=E1
*NCOPY, OLDSET=E1, NEWSET=E2, SHIFT, CHANGE=20
*NFILL, NSET=BOT
E1,E2,2,10
*NCOPY, OLDSET=BOT, NEWSET=TOP, SHIFT, CHANGE=200
*NFILL, NSET=BALL
BOT,TOP,2,100
*NODE
*NGEN, NSET=S1
*NCOPY, OLDSET=S1, NEWSET=S2, SHIFT, CHANGE=20
*NFILL, NSET=SLI_BOT
S1,S2,2,10
*NCOPY, OLDSET=SLI_BOT, NEWSET=SLI_TOP, SHIFT, CHANGE=200
*NFILL, NSET=SALL
SLI_BOT,SLI_TOP,2,100
*NSET, NSET=BC1
*NSET, NSET=NALL
BALL, SALL
*NMAP, NSET=NALL, TYPE=RECTANGULAR
*TRANSFORM, NSET=NALL
*ELEMENT, TYPE=C3D4
*ELGEN, ELSET=BLOCK
*ELGEN
*ELSET, ELSET=SLIDER, GEN
*ELSET, ELSET=EALL
SLIDER, BLOCK
*SOLID SECTION, ELSET=EALL, MATERIAL=MAT
*MATERIAL, NAME=MAT
*ELASTIC
30.0E6, 0.3
*DENSITY
10.0,
*ELSET, ELSET=BTOP,GEN
*ELSET, ELSET=SBOT
*surface, NAME=SL1
SBOT, S1
*surface, NAME=MA1
BTOP, S3
*CONTACT PAIR, INTERACTION=INT, TYPE=SURFACE TO SURFACE
SL1, MA1
*SURFACE INTERACTION, NAME=INT
*FRICTION
0.0,
*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,
ELEN,
*NODE FILE,FREQ=5
U,RF
*CONTACT FILE, MASTER=MA1
CSTRESS,CDISP
CAREA,
CFN,CFS
CMN,CMS
CFT,CMT
XN,XS,XT
*OUTPUT,FIELD
*ELEMENT OUTPUT, VARIABLE=PRESELECT
*NODE OUTPUT, VARIABLE=PRESELECT
*END STEP
*STEP, NLGEOM, INC=100, UNSYMM=YES
 SLIDE ACROSS TOP - MODIFY FRICTION
*STATIC
0.1,1.0
*BOUNDARY
SLI_TOP,2,2,-.15
SLI_TOP,1,1,4.
*CHANGE FRICTION, INTERACTION=INT
*FRICTION
0.3,
*END STEP
**
** step 4: Steady state dynamics, direct analysis
**
*STEP
*STEADY STATE DYNAMICS,DIRECT
20,100,5
*BOUNDARY,OP=NEW
BC1,1
BOT,2,3
SLI_TOP,1
SLI_TOP,2,2,0.1
SLI_TOP,3
*NODE FILE
U,
RF,
*EL FILE
E,
S,
*CONTACT FILE
*END STEP
**
** step 5: frequency extraction
**
*STEP
*FREQUENCY,EIGENSOLVER=LANCZOS
28,,,1
*BOUNDARY
BC1,1
BOT,2,3
*BOUNDARY,BASE NAME=MOVA
 SLI_TOP,1,1
*BOUNDARY,BASE NAME=MOVB
 SLI_TOP,2,2
*BOUNDARY,BASE NAME=MOVC
 SLI_TOP,3,3
*CONTACT FILE,FREQ=0
*NODE FILE,F=0
*EL FILE,F=0
*MODAL FILE
*NODE PRINT,F=0
*EL PRINT,F=0
*END STEP
**
** step 6: Steady state dynamics, subspace projection
**
*STEP
*STEADY STATE DYNAMICS,SUBSPACE PROJECTION,INTERVAL=RANGE
20,100,5
*BASE MOTION,BASE NAME=MOVA,AMPLITUDE=CONSTA,DOF=1,TYPE=DISPLACEMENT
*BASE MOTION,BASE NAME=MOVB,AMPLITUDE=CONSTB,DOF=2,TYPE=DISPLACEMENT
*BASE MOTION,BASE NAME=MOVC,AMPLITUDE=CONSTC,DOF=3,TYPE=DISPLACEMENT
*NODE FILE
TU,
RF,
*EL FILE
E,
S,
*CONTACT FILE
*END STEP