*HEADING
SIMPLE  TESTS, FINTE SLIDING, CGAX6                      :-- 
**RESTART,WRITE, FREQ=30
*NODE
1,1.,5.
2,2.,5.
3,2.,10.
4,1.,10.
5,1.5,5.
6,1.,7.5
7,1.5,7.5
8,2.,7.5
9,1.5,10.
10,1.9,3.0
11,2.4,3.0
12,2.9,3.0
22,1.9,12.0
23,2.4,12.0
24,2.9,12.0
*NGEN
10,22,3
11,23,3
12,24,3
*NSET, NSET=LT_N
1,4,6
*NSET, NSET=RT_N
12,15,18,21,24
*ELEMENT,TYPE=CGAX6,ELSET=LEFTEL
1,1,2,3,5,8,7
2,1,3,4,7,9,6
*ELEMENT,TYPE=CGAX6,ELSET=RTEL
3,10,12,18,11,15,14
4,10,18,16,14,17,13
5,16,18,24,17,21,20
6,16,24,22,20,23,19
*ELSET,ELSET=SOLID
LEFTEL, RTEL
*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
1,S2
*surface,NAME=RT
4,S3
6,S3
*CONTACT PAIR,INTERACTION=SLIDE
LEFT,RT
*BOUNDARY
LT_N,1,2
LT_N,5,5
RT_N,1,2
RT_N,5,5
**
**    step 1  :  interference fit, (radial intereference)
**
*STEP, INC=20, NLGEOM
           SHRINK FIT
*STATIC 
0.1,1.,0.1,0.2
*CONTACT INTERFERENCE,SHRINK
LEFT, RT
*NODE PRINT, F=0
*EL PRINT, F=0
*OUTPUT,FIELD,FREQ=0
*ELEMENT OUTPUT
*OUTPUT,FIELD,FREQ=0
*NODE OUTPUT
*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); sliding upwards
**
*STEP,PERT,  NLGEOM
 PERT :- SLIDING UPWARDS
*STATIC
*BOUNDARY, OP=MOD
RT_N,2,,0.1
*NODE PRINT, F=0
*EL PRINT, F=0
*OUTPUT,FIELD,FREQ=0
*ELEMENT OUTPUT
*OUTPUT,FIELD,FREQ=0
*NODE OUTPUT
*OUTPUT,FIELD,FREQ=50
*CONTACT OUTPUT,VARIABLE=PRESELECT,SLAVE=LEFT,MASTER=RT
*CONTACT PRINT, SLAVE=LEFT , MASTER=RT, F=50
*ENDSTEP
**
**     step 3 : linear perturbation (about shrink fit); twist 
**
*STEP, PERT, NLGEOM
  PERT: TWISTING
*STATIC
*BOUNDARY, OP=MOD
RT_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: UNSYMM, linear perturbation, slide and twist
** 	          with shrink-fit base state.
**
*STEP,  PERT, NLGEOM, UNSYMM=YES
*STATIC
*BOUNDARY
RT_N,5,,0.1
RT_N,2,,0.1
*OUTPUT,FIELD,FREQ=50
*CONTACT OUTPUT,VARIABLE=PRESELECT,SLAVE=LEFT,MASTER=RT
*CONTACT PRINT, SLAVE=LEFT , MASTER=RT, F=50
*ENDSTEP
**
**       step 5: NLGEOM, UNSYMM, twist and sliding
**
*STEP, NLGEOM, UNSYMM=YES
*STATIC
0.1,1.0
*CONTROLS,PARAMETERS=FIELD
1.0E-6, 
*BOUNDARY
RT_N,2,,0.1
RT_N,5,,0.1
*ENDSTEP