*HEADING
 TOW OF A PIPE WITH DRAG CHAINS (WITH CONTACT INTERFERENCE) 
*NODE
1,1000.
6, 
11,700.,400.
*NGEN
1,6
*ELEMENT,TYPE = B23H
1,1,2
*ELGEN,ELSET=BEAMS
1,5
*ELEMENT,TYPE=GAPSPHER,ELSET=CABLE
101,11,1
*ELEMENT,TYPE=DRAG2D
102,1
103,2
*ELGEN,ELSET=CHAIN2
103,5
*ELSET,ELSET=CHAIN1
102, 
*ELSET,ELSET=CHAINS
CHAIN1,CHAIN2
*BEAM GENERAL SECTION,SECTION=PIPE,ELSET=BEAMS
.375,.025
,,-1.
4.32E9, 
*DRAG CHAIN,ELSET=CHAIN1
25.,125.
*DRAG CHAIN,ELSET=CHAIN2
5.,25.
*GAP,ELSET=CABLE
500., 
*AMPLITUDE,NAME=A1
0.,0.,1.,0.
**
** A small initial stress and soft springs are 
** used to control the singularity.
**
*INITIAL CONDITIONS,TYPE=STRESS
BEAMS,1.E-10
**
*ELEMENT,TYPE=SPRING1,ELSET=SPR-X
1003,3
1005,5
*ELEMENT,TYPE=SPRING1,ELSET=SPR-Y
2003,3
2005,5
*ELEMENT,TYPE=SPRING1,ELSET=SPR-RZ
3003,3
3005,5
*SPRING,ELSET=SPR-X
1,
1.E-3,
*SPRING,ELSET=SPR-Y
2,
1.E-3,
*SPRING,ELSET=SPR-RZ
6,
1.E-3,
*STEP,NLGEOM,INC=200
  TOW PIPELINE
*STATIC
0.01,1.,,0.05
*BOUNDARY
11,1
11,2,2,1000.
11,3
*CONTROLS,ANALYSIS=DISCONTINUOUS
*CONTROLS, PARAMETERS=FIELD

,0.0,
*CONTACT INTERFERENCE,TYPE=ELEMENT,AMPLITUDE=A1
CABLE,0.
*EL FILE,FREQUENCY=10,ELSET=CABLE
S, 
*OUTPUT,FIELD,FREQ=10
*ELEMENT OUTPUT,ELSET=CABLE
S,
*PRINT,CONTACT=YES,RESIDUAL=YES
*EL PRINT,ELSET=CHAINS
S, 
*EL PRINT,ELSET=CABLE
S, 
*END STEP