*HEADING
 TOW OF A PIPE WITH [DRAG3D] CHAINS (WITH CONTACT INTERFERENCE) 
 THE MODEL  REPRODUCES THE RESULTS OF THE 2D MODEL (DRAG2D)
*RESTART,WRITE,FREQ=2
*NODE
1,1000,0.0,10.0
6,0.0,0.0,10.0
11,700,400,10.0
9999,0.,0.0,0.0
*NGEN
1,6
*ELEMENT,TYPE=B33H
1,1,2
*ELGEN,ELSET=PIPE
1,5
*ELEMENT,TYPE=GAPSPHER,ELSET=CABLE
101,11,1
*ELEMENT,TYPE=DRAG3D, ELSET=CHAIN1
102,1,9999
103,2,9999
*ELEMENT,TYPE=DRAG3D, ELSET=CHAIN2
104,3,9999
105,4,9999
106,5,9999
107,6,9999
*ELSET,ELSET=CHAINS
CHAIN1,CHAIN2
*RIGID SURFACE, ELSET=CHAINS, TYPE=CYLINDER
-2000,-2000,0,0,-2000,0
-2000,1000,0
START,-2000
LINE,10000
*BEAM GENERAL SECTION,SECTION=PIPE,ELSET=PIPE
.375,.025
0,0,-1.0
4.32E9, 
*DRAG CHAIN,ELSET=CHAIN1
131.0,0.3,4.0
*DRAG CHAIN,ELSET=CHAIN2
26.20,0.1,20.0
*GAP,ELSET=CABLE
500.0, 
*AMPLITUDE,NAME=A1
0.,0.,1.,0.0
**
** A small initial stress and soft springs are 
** used to control the singularity.
**
*INITIAL CONDITIONS,TYPE=STRESS
PIPE,1.E-15
**
*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-RX
4003,3
4005,5
*ELEMENT,TYPE=SPRING1,ELSET=SPR-RY
5003,3
5005,5
*ELEMENT,TYPE=SPRING1,ELSET=SPR-RZ
6003,3
6005,5
*SPRING,ELSET=SPR-X
1,
1.E-3,
*SPRING,ELSET=SPR-Y
2,
1.E-3,
*SPRING,ELSET=SPR-RX
4,
1.E-3,
*SPRING,ELSET=SPR-RY
5,
1.E-3,
*SPRING,ELSET=SPR-RZ
6,
1.E-3,
*STEP,NLGEOM,INC=10000
 TOW PIPELINE
*STATIC
0.01,1.0,,0.5
*BOUNDARY
11,2,2,1000.
11,1,1,0
11,3,3,0
9999,1,6
1,3,3
2,3,3
3,3,3
4,3,3
5,3,3
6,3,3
*CONTROLS,PARAMETERS=TIME INCREMENTATION
15,15,
*CONTROLS,PARAMETERS=FIELD
,0.1
,0.0,
*CONTACT INTERFERENCE,TYPE=ELEMENT,AMPLITUDE=A1
CABLE,0.0
*EL PRINT,ELSET=PIPE,FREQUENCY=1
SF,
NFORC, 
*EL PRINT,ELSET=CHAINS
S,
E, 
*EL PRINT,ELSET=CABLE
S,
E, 
*PRINT,CONTACT=YES,RESIDUAL=YES, FREQ=10
*EL FILE,ELSET=CHAINS,FREQUENCY=1
S,
E, 
*OUTPUT,FIELD,FREQ=1,VAR=PRESELECT
*ELEMENT OUTPUT,ELSET=CHAINS
S,
E,
*ENERGY FILE,FREQ=10
*OUTPUT,HISTORY,FREQ=10
*ENERGY OUTPUT,VARIABLE=PRESELECT
*END STEP