*HEADING
 : Adjust contact surface normal at symmetry plane
 Small sliding with CPE4 elements
 Local rectangular coordinate system.
*SYSTEM
 0.0, 0.0, 0.0, 1., 1., 0.
*NODE, NSET=NALL
  1,  0.0,  1.5, 0.0
  5,  1.5,  0.0, 0.0
 11,  0.0,  2.0, 0.0
 15,  2.0,  0.0, 0.0 
 21,  0.0,  2.5, 0.0
 25,  2.5,  0.0, 0.0
 31,  0.0,  2.6, 0.0
 35,  2.6,  0.0, 0.0
 41,  0.0,  3.0, 0.0
 45,  3.0,  0.0, 0.0
 51,  0.0,  3.5, 0.0
 55,  3.5,  0.0, 0.0
 99,  0.0, 0.0, 0.0
*NGEN, LINE=C, NSET=NALL
   1,  5, 1, 99
  11, 15, 1, 99
  21, 25, 1, 99
  31, 35, 1, 99
  41, 45, 1, 99
  51, 55, 1, 99
*ELEMENT,TYPE=CPE4
  1,   1,  2, 12, 11
  11, 31, 32, 42, 41
*ELGEN,ELSET=EALL
  1, 4, 1, 1, 2, 10, 4
 11, 4, 1, 1, 2, 10, 4
*solid section,elset=EALL,mat=MAT1
*MATERIAL,NAME=MAT1
*ELASTIC
 3000.0,0.2
*ELSET,ELSET=EIN
 5,6,7,8
*ELSET,ELSET=EOUT
 11,12,13,14
*surface, NAME=MASTER
 EIN,
*surface, NAME=SLAVE
 EOUT,
*CONTACT PAIR,INTERACTION=NONE,SMALL SLIDING
 SLAVE,MASTER
*SURFACE INTERACTION,NAME=NONE
*NSET, NSET=NXSYMM
 1, 11, 21, 31, 41, 51
*NSET, NSET=NYSYMM
 5, 15, 25, 35, 45, 55
*TRANSFORM, NSET=NALL
 1.,1.,0., -1., 1., 0.
*BOUNDARY
 NXSYMM, XSYMM
 NYSYMM, YSYMM
**
** STEP 1 : Apply pressure load
**
*STEP, NLGEOM, INC=50
*STATIC
 ,1.0
*DLOAD
 15, P3, 100.0
 16, P3, 100.0
 17, P3, 100.0
 18, P3, 100.0
*PRINT, CONTACT=YES
*NODE PRINT, F=0
*EL PRINT, F=0
*CONTACT PRINT, FREQ=100
*CONTACT FILE, MASTER=MASTER, SLAVE=SLAVE, FREQ=100
 CSTRESS, CDISP,
*END STEP
**
** STEP 2 : Remove pressure load
**
*STEP, NLGEOM, INC=50
*STATIC
,1.0
*DLOAD, OP=NEW
 15, P3, 0.0
 16, P3, 0.0
 17, P3, 0.0
 18, P3, 0.0
*PRINT, CONTACT=YES
*NODE PRINT, F=0
*EL PRINT, F=0
*CONTACT PRINT, FREQ=100
*CONTACT FILE, MASTER=MASTER, SLAVE=SLAVE,  FREQ=100
 CSTRESS, CDISP,
*END STEP