*HEADING
SIMPLE  TESTS, FINITE SLIDING, CGAX4                  :-- 
**RESTART,WRITE, FREQ=30
*NODE
1,1.,5.
2,2.,5.
3,2.,10.
4,1.,10.
5,1.9,3.0
6,2.9,3.0
7,1.9,7.5
8,2.9,7.5
9,1.9,12.0
10,2.9,12.0
*ELEMENT,TYPE=CGAX4,ELSET=LEFTEL
1,1,2,3,4
*ELEMENT,TYPE=CGAX4,ELSET=RTEL
3,5,6,8,7
4,7,8,10,9
*ELSET,ELSET=SOLID
LEFTEL, RTEL
*NSET, NSET=LT_N
6, 
*NSET, NSET=RT_N
1, 
*NSET,NSET=SL_N
2,3
*MPC
TIE,4,1
*MPC
TIE,8,10
TIE,10,6
*TRANSFORM, NSET=SL_N
0.,1.,0.,-1.,0.,0.
*SOLID SECTION,ELSET=SOLID,MATERIAL=SOLMAT
*MATERIAL,NAME=SOLMAT
*ELASTIC
30.E6,0.30
*SURFACE INTERACTION,NAME=SLIDE
 1., 
*FRICTION, ANISOTROPIC
0.1,0.2
*surface,NAME=LEFT
LEFTEL,S2
*surface,NAME=RT
RTEL,S4
*CONTACT PAIR,INTERACTION=SLIDE
LEFT,RT
*BOUNDARY
RT_N,1,2
RT_N,5,5
LT_N,1,2
LT_N,5,5
**
**    step 1  :  interference fit, (radial intereference)
**
*STEP, INC=20, NLGEOM
           SHRINK FIT
*STATIC 
0.1,1.,0.1,0.2
*CONTROLS,PARAMETERS=FIELD
1.0E-6, 
*CONTACT INTERFERENCE,SHRINK
LEFT, RT
*NODE PRINT, F=100, GLO=YES
U, 
*EL PRINT, F=0
*OUTPUT,FIELD,FREQ=0
*ELEMENT OUTPUT
*OUTPUT,FIELD,FREQ=100
*NODE OUTPUT
U,
*OUTPUT,FIELD,FREQ=50
*CONTACT OUTPUT,VARIABLE=PRESELECT,SLAVE=LEFT,MASTER=RT
*CONTACT PRINT, SLAVE=LEFT , MASTER=RT, F=50
*ENDSTEP
**
**     step 2 : linear perturbation (about shrink fit):
**
**     Multiple load cases:
**       (1)  sliding upwards
**       (2)  twist
**
*STEP,PERT,  NLGEOM
*STATIC
*LOAD CASE, NAME=SLIDING_UPWARDS
*BOUNDARY, OP=MOD
LT_N,2,,0.1
*END LOAD CASE
*LOAD CASE, NAME=TWIST
*BOUNDARY, OP=MOD
LT_N,5,,0.1
*END LOAD CASE
*OUTPUT,FIELD,FREQ=50
*CONTACT OUTPUT,VARIABLE=PRESELECT,SLAVE=LEFT,MASTER=RT
*CONTACT PRINT, SLAVE=LEFT , MASTER=RT, F=50
*NODE PRINT, F=100,GLO=YES
U, 
*EL PRINT, F=0
*OUTPUT,FIELD,FREQ=0
*ELEMENT OUTPUT
*OUTPUT,FIELD,FREQ=100
*NODE OUTPUT
U,
*ENDSTEP
**
**     step 3: UNSYMM, linear perturbation, slide and twist
** 	          with shrink-fit base state.
**
*STEP,  PERT, NLGEOM, UNSYMM=YES
*STATIC
*BOUNDARY
LT_N,2,,0.1
LT_N,5,,0.1
*OUTPUT,FIELD,FREQ=50
*CONTACT OUTPUT,VARIABLE=PRESELECT,SLAVE=LEFT,MASTER=RT
*CONTACT PRINT, SLAVE=LEFT , MASTER=RT, F=50
*ENDSTEP
**
**       step 4: NLGEOM, UNSYMM, twist and sliding
**
*STEP, NLGEOM, UNSYMM=YES
*STATIC
0.1,1.0
*CONTROLS,PARAMETERS=FIELD
1.0E-6, 
*BOUNDARY
LT_N,2,,0.1
LT_N,5,,0.1
*NODE PRINT, GLO=YES, F=100
U, 
*OUTPUT,FIELD,FREQ=100
*NODE OUTPUT
U,
*ENDSTEP