*HEADING
SIMPLE  TESTS, SMALL SLIDING, CGAX4                  :--
**RESTART,WRITE, FREQ=30
*NODE
1,1.,5.
2,2.,5.
3,2.,10.
4,1.,10.
5,1.9,5.
6,2.9,5.
7,2.9,10.
8,1.9,10.
*ELEMENT,TYPE=CGAX4,ELSET=LEFTEL
1,1,2,3,4
*ELEMENT,TYPE=CGAX4,ELSET=RTEL
3,5,6,7,8
*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
LEFTEL,S2
*surface,NAME=RT
RTEL,S4
*CONTACT PAIR,INTERACTION=SLIDE, SMALL SLIDING, TYPE=SURFACE TO SURFACE
LEFT,RT
*BOUNDARY
1,1,2
4,1,2
1,5,5
4,5,5
6,1,2
7,1,2
6,5,5
7,5,5
**
**    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=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
6,2,,0.1
7,2,,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
6,5,,0.1
7,5,,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
6,2,,0.1
6,5,,0.1
7,5,,0.1
7,2,,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
6,2,,0.1
6,5,,0.1
7,5,,0.1
7,2,,0.1
*ENDSTEP