*HEADING
: CONTACT PAIR WITH & WITHOUT FRICTION, BETWEEN RIGID & PIPES [PIPE31]
** Contact Features Tested: 
**	*FRICTION, (mu=0 and mu=0.3)
*NODE
1, 6.,0.
2, 7.,0.
1000,0.
*ELEMENT,TYPE=PIPE31,ELSET=BEAM
 1, 1,2
*BEAM SECTION,SECT=PIPE,ELSET=BEAM,MATERIAL=MAT1
 1.00, 0.01
*MATERIAL,NAME=MAT1
*DENSITY
 0.284e+0
*ELASTIC
 30.E6,.3
*RIGID BODY,ANALYTICAL SURFACE=BSURF,REFNODE=1000
*SURFACE,NAME=BSURF,TYPE=SEGMENTS
 START,5.5, 0.0
 LINE,7.5, 0.0
*NSET, NSET=BEAM_NODES
 1, 2
*SURFACE,NAME=ASURF, TYPE=NODE
BEAM_NODES
*AMPLITUDE, NAME=LINEAR
 0.0, 0.0
 1.0, 1.0 
**
** Step 1: Apply pressure normal to rigid surface
**
*STEP
*DYNAMIC, EXPLICIT
 , 1.0
*CONTACT PAIR,INTERACTION=SMOOTH_INTR
ASURF,BSURF
*SURFACE INTERACTION,NAME=SMOOTH_INTR
*FRICTION
0.0, 
*DLOAD
 1,PY,-500.
*BOUNDARY
 1,1
 1,3,6
 2,3,6
 1000,1,6
*OUTPUT,FIELD
*CONTACT OUTPUT
 CSTRESS, CFORCE
** CSTRESS, CFORCE, FSLIPR
*END STEP
**
** step 2: slide to the left w/ friction
**
*STEP
*DYNAMIC, EXPLICIT
, 1.0
*CONTACT PAIR, OP=DELETE
ASURF,BSURF
*CONTACT PAIR,INTERACTION=FRIC_INTR, MECHANICAL CONSTRAINT=PENALTY, OP=ADD
ASURF,BSURF
*SURFACE INTERACTION,NAME=FRIC_INTR
*FRICTION
0.3,
*BOUNDARY, AMPLITUDE=LINEAR
1,1,,0.1
2,1,,0.1
*OUTPUT,FIELD
*CONTACT OUTPUT
 CSTRESS, CFORCE
** CSTRESS, CFORCE, FSLIPR
*ENDSTEP