Coupling Specification
3. Text for describing the coupling system, 2 input lines.
TXCPL

TXCPL: character(60)
: Character string describing the coupling
The data group in the four previous input lines must be followed by a specification of one of the following coupling models. This means that in the case of several or multiple couplings, the previous data group has to be repeated.
4. Simple wire coupling
Connection point 1  Alternative 1: 1 input line
CHBDY1 XBDY1 YBDY1 ZBDY1

CHBDY1: character(8)
: Identifier for body 1 
XBDY1: real
: Xcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
YBDY1: real
: Ycoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
ZBDY1: real
: Zcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\).
Connection point 1  Alternative 2: 1 input line
CPL_NAME1

CPL_NAME1: character(32)
: Name (identifier) of coupling point in end 1
CPL_NAME1
must have been defined as a coupling point in data group
"COUPling POINt"
.
CPL_NAME1
must be identical to identifier CHCOPO
.
Connection point 2  Alternative 1: 1 input line
CHBDY2 XBDY2 YBDY2 ZBDY2

CHBDY2: character(8)
: Identifier for body 2 
XBDY2: real
: Xcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
YBDY2: real
: Ycoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
ZBDY2: real
: Zcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\).
Connection point 2  Alternative 2: 1 input line
CPL_NAME2

CPL_NAME2: character(32)
: Name (identifier) of coupling point in end 2
CPL_NAME2
must have been defined as a coupling point in data group
"COUPling POINt"
.
CPL_NAME2
must be identical to identifier CHCOPO
. CPL_NAME2
must
be different from CPL_NAME1
.
1 input line if guide points are wanted ( NGUIDE > 0 )
NGUIDE

NGUIDE: integer
: Number of guide points
= 0
if no guide points are specified

NGUIDE input lines
CHGUPO IACTIVE

CHGUPO: character(32)
: Identifier for guide point 
IACTIVE: integer, default: 1
:
= 0
: Guide point not entered on line 
= 1
: Coupling point entered on line

1 input line
EA RLEN FLEXC DAMPSW IREST EHLA HLACON1 HLACON2 ICT

EA: real
: Wire cross section stiffness, \(\mathrm {[F]}\) 
RLEN: real
: Initial, unstretched wire length, \(\mathrm {[L]}\) 
FLEXC: real, default: 0
: Connection flexibility, \(\mathrm {[L/F]}\) 
DAMPSW: real, default: 0
: Material damping \(\mathrm {[FT]}\). \(\mathrm {Force=dampsw*(\Delta L/\Delta t)/L}\) 
IREST: integer, default: 0
: Flag for "Restoring Coupling", only used inSTAMOD

EHLA: integer, default: 0
: HLA export flag for simplified wire,
= 0
: No export 
= 1
: HLA Export


HLACON1: integer, default: 0
: HLA control flag for connection of line end 1
= 0
: not HLA connectable 
= 1
: HLA connectable


HLACON2: integer, default: 0
: HLA control flag for connection of line end 2,
= 0
: not HLA connectable 
= 1
: HLA connectable


ICT: integer, default: 0
: Constant tension control
= 0
: Disabled 
= 1
: Enabled

FLEXC
(inverse of stiffness) is the flexibility in the wire attachment
point. This flexibility should account both for flexibility in the
construction and elasticity in the wire between the winch and the used
wire attachment point.
DAMPSW
is specified material damping in the line. The value can
normally be set to 12% of E * A, where E is the modulus of elasticity
and A is the crosssectional area.
If EHLA = 1, 1 input line, HLA name of simple wire object,
CHCHLA

CHCHLA: character(120)
: Character string describing HLA coupling object name
If HLACON1 = 1, 1 input line, HLA name of connectable line end 1
CHCON1

CHCON1: character(120)
: Character string describing HLA connectable line end 1
If HLACON2 = 1, 1 input line, HLA name of connectable line end 2
CHCON2

CHCON2: character(120)
: Character string describing HLA connectable line end 2
If ICT = 1, 1 input line
Wire length will be adjusted trying to keep tension within
\(\mathrm {TSETDEADB/2}\) and
\(\mathrm {TSET+DEADB/2}\). The change in wire length is
constrained by VMAX
.
TSET DEADB VMAX

TSET: real
: Tension set point \(\mathrm {[F]}\) 
DEADB: real
: Tension control deadband \(\mathrm {[F]}\) 
VMAX: real
: Maximum run speed of winch controlling tension \(\mathrm {[L/T]}\) 
TACT: real, default=0
: Activation time of controller \(\mathrm {[T]}\) 
TDEACT: real, default=0
: Deactivation time of controller\(\mathrm {[T]}\)
The wire length will not be adjusted until simulation time is larger
than or equal to the given activation time, TACT
. If the controller
deactivation time, TDEACT
, is less than or equal to the activation
time the controller will always remain active.
Element failure, 1 input line
IFMOCO FTIME BTENS

IFMOCO: integer
: Failure mode of coupling element
= 0
: no failure 
= 1
: failure by exceedance ofBTENS
after specified time
The coupling element breaks when both
FTIME
andBTENS
are exceeded


= 2
: failure activated after specified time if Tens< BTENS


FTIME: real
: Earliest possible time of failure, \(\mathrm {[T]}\) 
BTENS: real
: Breaking strength, \(\mathrm {[F]}\)
5. Multiple wire coupling
Multiple wire couplings makes it possible to model several wire segments connected in a common branch point, for example a crane wire with a sling arrangement, connected in the hook.
Each of the wire segments must be separately specified by
COUPling DATA
and MULTiple WIRE COUPling
data groups, e.g. each
segment is treated as a separate coupling. Typically 24 segments are
attached to one body (lifted object), and 1 segment to another body
(crane vessel).
Connection points  Alternative 1: 1 input line
CHBRAN CHBDY XBDY YBDY ZBDY

CHBRAN: character(8)
: Identifier for branch point. 
CHBDY: character(8)
: Identifier for body. 
XBDY: real
: Xcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
YBDY: real
: Ycoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
ZBDY: real
: Zcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\).
Connection points  Alternative 2: 1 input line
CHBRAN CPL_NAME2

CHBRAN: character(8)
: Identifier for branch point. 
CPL_NAME2: character(32)
: Name (identifier) of coupling point in end 2
1 input line
EA RLEN FLEXC DAMPSW IREST EHLA

EA: real
: Wire cross section stiffness, \(\mathrm {[F]}\). 
RLEN: real
: Initial, unstretched wire length, \(\mathrm {[L]}\). 
FLEXC: real, default: 0
: Connection flexibility, \(\mathrm {[L/F]}\). 
DAMPSW: real, default: 0
: Material damping \(\mathrm {[FT]}\). \(\mathrm {Force=dampsw*(\Delta L/\Delta t)/L}\) 
IREST: integer, default: 0
: Flag for "Restoring Coupling", only used inSTAMOD

EHLA: integer, default: 0
: HLA export flag for multiple wire element
= 0
: No export 
= 1
: HLA export

FLEXC
(inverse of stiffness) is the flexibility in the wire attachment
point. This flexibility should account both for flexibility in the
construction and elasticity in the wire between the winch and the used
wire attachment point.
DAMPSW
is specified material damping in the line. The value can
normally be set to 12% of E*A, where E is the modulus of elasticity and
A is the crosssectional area.
If EHLA = 1, 1 input line, HLA name of multiple wire object,
CHCHLA

CHCHLA: character(120)
: Character string describing HLA coupling object name
Element failure, 1 input line
IFMOCO FTIME BTENS

IFMOCO: integer
: Failure mode of coupling element
= 0
: no failure 
= 1
: failure by exceedance ofBTENS
after specified time


FTIME: real
: Earliest possible time of failure, \(\mathrm {[T]}\). 
BTENS: real
: Breaking strength, \(\mathrm {[F]}\).
The coupling element breaks when both FTIME
and BTENS
are exceeded
6. Lift line coupling
The lift line coupling is a single line model, which includes in a simplified way the following features:

drag forces on the line

static line weight

longitudinal inertia forces due to vertical acceleration at both ends.
The model assumes that the line is straight.
Connection point end 1  Alternative 1: 1 input line
CHBDY1 XBDY1 YBDY1 ZBDY1

CHBDY1: character(8)
: Identifier for body 1 
XBDY1: real
: Xcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
YBDY1: real
: Ycoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
ZBDY1: real
: Zcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\).
Connection point end 1  Alternative 2: 1 input line
CPL_NAME1

CPL_NAME1: character(32)
: Name (identifier) of coupling point in end 1
CPL_NAME1
must have been defined as a coupling point in data group
"COUPling POINt"
.
CPL_NAME1
must be identical to identifier CHCOPO
Connection point end 2  Alternative 1: 1 input line
CHBDY2 XBDY2 YBDY2 ZBDY2

CHBDY2: character(8)
: Identifier for body 2 
XBDY2: real
: Xcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
YBDY2: real
: Ycoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
ZBDY2: real
: Zcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\).
Connection point end 2  Alternative 2: 1 input line
CPL_NAME2

CPL_NAME2: character(32)
: Name (identifier) of coupling point in end 2
CPL_NAME2
must have been defined as a coupling point in data group
"COUPling POINt"
.
CPL_NAME2
must be identical to identifier CHCOPO
. CPL_NAME2
must
be different from CPL_NAME1
.
1 input line
NEL IACC EHLA HLACON1 HLACON2

NEL: integer
: Number of elements in the line 
IACC: integer, default: 0
: Flag for including acceleration of the line
= 0
: No acceleration of the line included 
= 1
: Acceleration of the line included in the force calculations


EHLA: integer, default: 0
: HLA export flag for lift line,
= 0
: No export 
= 1
: HLA Export


HLACON1: integer, default: 0
: HLA control flag for connection of line end 1
= 0
: not HLA connectable 
= 1
: HLA connectable


HLACON2: integer, default: 0
: HLA control flag for connection of line end 2
= 0
: not HLA connectable 
= 1
: HLA connectable

The model for including line acceleration in the line force calculations is simplified, assuming linear variation of acceleration along the length.
If EHLA = 1, 1 input line, HLA name of lift line object
CHCHLA

CHCHLA: character(120)
: Character string describing HLA coupling object name
If HLACON1 = 1, 1 input line, HLA name of connectable line end 1
CHCON1

CHCON1: character(120)
: Character string describing HLA connectable line end 1
If HLACON2 = 1, 1 input line, HLA name of connectable line end 2
CHCON2

CHCON2: character(120)
: Character string describing HLA connectable line end 2
1 input line
DIA EMOD EMFACT RLEN FLEXC DAMPSW

DIA: real
: Segment diameter, \(\mathrm {[L]}\) 
EMOD: real
: Modulus of elasticity \(\mathrm {[F/L^2]}\) 
EMFAC: real
: Factor of elasticity
= 2
: For chains 
= 1
: For other segment types


RLEN: real
: Initial, unstretched line length, \(\mathrm {[L]}\) 
FLEXC: real, default: 0
: Connection flexibility, \(\mathrm {[L/F]}\) 
DAMPSW: real, default: 0
: Material damping \(\mathrm {[FT]}\). \(\mathrm {Force=DAMPSW*(\Delta L/\Delta t)/L}\)
Total stiffness, \(\mathrm {EA=EMOD\times EMFAC\times DIA^2\times \pi /4}\)
FLEXC
(inverse of stiffness) is the flexibility in the wire attachment
point. This flexibility should account both for flexibility in the
construction and elasticity in the wire between the winch and the used
wire attachment point.
DAMPSW
is material damping in the line. The value can normally be set
to 12% of E*A, where E is the modulus of elasticity and A is the
crosssectional area.
1 input line
UWIA WATFAC CDN CDL

UWIA: real
: Unit weight in air, \(\mathrm {[F/L]}\) 
WATFAC: real
: The ratio of weight in water to weight in air.
Normally 0.81 for wire and 0.87 for chain


CDN: real
: Transverse drag coefficient of the line 
CDL: real
: Longitudinal drag coefficient of the line . 
Drag force/length
= 0.5
*RHOW
*DIA
*CDN
*VN
\(\mathrm {^2\quad }\) Transverse 
Drag force/length
= 0.5
*RHOW
*DIA
*CDL
*VL
\(\mathrm {^2\quad }\) Longitudinal
Element failure, 1 input line
IFMOCO FTIME BTENS

IFMOCO: integer
: Failure mode of coupling element
= 0
: no failure 
= 1
: failure by exceedance ofBTENS
after specified time
The coupling element breaks when both
FTIME
andBTENS
are exceeded


= 2
: failure activated after specified time if Tens< BTENS


FTIME: real
: Earliest possible time of failure, \(\mathrm {[T]}\) 
BTENS: real
: Breaking strength, \(\mathrm {[F]}\)
Note! The coupling element breaks when both FTIME
and BTENS
are
exceeded.
7. Forceelongation with fixed attack points
Connection point 1  Alternative 1: 1 input line
CHBDY1 XBDY1 YBDY1 ZBDY1

CHBDY1: character(8)
: Identifier for body 1 
XBDY1: real
: Xcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
YBDY1: real
: Ycoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
ZBDY1: real
: Zcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\).
Connection point 1  Alternative 2: 1 input line
CPL_NAME1

CPL_NAME1: character(32)
: Name (identifier) of coupling point in end 1
CPL_NAME1
must have been defined as a coupling point in data group
"COUPling POINt"
.
CPL_NAME1
must be identical to identifier CHCOPO
.
Connection point 2  Alternative 1: 1 input line
CHBDY2 XBDY2 YBDY2 ZBDY2

CHBDY2: character(8)
: Identifier for body 2 
XBDY2: real
: Xcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
YBDY2: real
: Ycoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
ZBDY2: real
: Zcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\).
Connection point 2  Alternative 2: 1 input line
CPL_NAME2

CPL_NAME2: character(32)
: Name (identifier) of coupling point in end 2
CPL_NAME2
must have been defined as a coupling point in data group
"COUPling POINt"
.
CPL_NAME2
must be identical to identifier CHCOPO
. CPL_NAME2
must
be different from CPL_NAME1
.
1 input line
NPT IMETH EXP INTPOC VEMIC EHLA

NPT: integer
: Number of points in characteristics 
IMETH: integer
: Method for initialisation of coupling element
= 3
: Spring, coordinates of both end points are given 
= 5
: Constant tension winch, coordinates of both end points are given. Maximum and minimum tension specified in the characteristic will not be exceeded.


EXP: real, default: 1
: Exponent of velocity in damping term 
INTPOC: integer, default: 1
: Interpolation method = 1, 2, 3 or 4
=1
: Linear force, linear damping. 
=2
: Linear force, parabolic damping. 
=3
: Parabolic force, linear damping. 
=4
: Parabolic force, parabolic damping.


VEMIC: real, default: 0
: Velocity limit for friction force (EXP = 0) See below. 
EHLA: integer, default: 0
: HLA export flag for coupling element
= 0
: No export 
= 1
: HLA export

Small velocities and EXP=0
. will result in problems in finding
equilibrium position because the friction force (which may be relatively
large) suddenly can change sign. To avoid this the value EXPD=1
is
used when Abs(vel.)<VEMIN
and EXPD<1
.
The damping force (EXP=1
) for Vel`=VEMIC` is equal to Damping force
(`EXP=`as given).
If EHLA = 1, 1 input line, HLA name of forceelongation object,
CHCHLA

CHCHLA: character(120)
: Character string describing HLA coupling object name
NPT input lines.
DIST FORCE DAMP

DIST: real
: Distance between end points, \(\mathrm {[L]}\). 
FORCE: real
: Force in element, positive values signify attraction of the bodies, \(\mathrm {[F]}\). 
DAMP: real
: Damping coefficient, \([F(T/L)^{\mathrm {EXP}}]\).
Distances are to specified in increasing order and can not be negative.
Element failure, 1 input line (Shall be given for all values of IMETH)
IFMOCO FTIME BTENS

IFMOCO: integer
: Failure mode of coupling element
= 0
: No failure 
= 1
: Failure by exceeding the tension after specified time. 
= 2
: Activated after specified time if Tens< BTENS


FTIME: real
: Earliest possible time of failure, \(\mathrm {[T]}\). 
BTENS: real
: Breaking strength, \(\mathrm {[F]}\).
Note! The coupling element breaks when both FTIME
and BTENS
are
exceeded
8. Docking cone coupling
Connection point 1  Alternative 1: 1 input line
CHBDY1 XBDY1 YBDY1 ZBDY1

CHBDY1: character(8)
: Identifier for body 1 
XBDY1: real
: Xcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
YBDY1: real
: Ycoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
ZBDY1: real
: Zcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\).
Connection point 1  Alternative 2: 1 input line
CPL_NAME1

CPL_NAME1: character(32)
: Name (identifier) of coupling point in end 1
CPL_NAME1
must have been defined as a coupling point in data group
"COUPling POINt"
.
CPL_NAME1
must be identical to identifier CHCOPO
.
Connection point 2  Alternative 1: 1 input line
CHBDY2 XBDY2 YBDY2 ZBDY2

CHBDY2: character(8)
: Identifier for body 2 (Body with cone) 
XBDY2: real
: Xcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
YBDY2: real
: Ycoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
ZBDY2: real
: Zcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\).
Connection point 2  Alternative 2: 1 input line
CPL_NAME2

CPL_NAME2: character(32)
: Name (identifier) of coupling point in end 2
CPL_NAME2
must have been defined as a coupling point in data group
"COUPling POINt"
.
CPL_NAME2
must be identical to identifier CHCOPO
. CPL_NAME2
must
be different from CPL_NAME1
1 input line
NPT EXP INTPOC VEMIC EHLA

NPT: integer
: Number of points in characteristics 
EXP: real, default: 1
: Exponent of velocity in damping term, 
INTPOC: integer, default: 1
: Interpolation method = 1, 2, 3 or 4
=1
: Linear force, linear damping. 
=2
: Linear force, parabolic damping. 
=3
: Parabolic force, linear damping. 
=4
: Parabolic force, parabolic damping.


VEMIC: real, default: 0
: Velocity limit for friction force (EXP = 0
). See below. 
EHLA: integer, default: 0
: HLA export flag for coupling element
= 0
: No export 
= 1
: HLA export

Small velocities and EXP=0
will result in problems in finding
equilibrium position because the friction force (which may be relatively
large) suddenly can change sign. To avoid this the value EXPD=1
is
used when Abs(vel.)<VEMIN
and EXPD<1
.
The damping force (EXP=1
) for Vel`=VEMIC` is equal to Damping force
(`EXP=`as given).
For EHLA = 1, 1 input line
CHCHLA

CHCHLA: character(120)
: Character string describing HLA coupling object name
1 input line
RADMAX FRIC

RADMAX: real
: Maximum radial distance at entry 
FRIC: real
: Friction coefficient for sliding along the cone or cylinder surface
1 input line
DV1 DV2 DV3

DV1: real, default: 0
: Direction vector, xcomponent 
DV2: real, default: 0
: Direction vector, ycomponent 
DV3: real, default: 1
: Direction vector, zcomponent
Direction vectors of guide axis are defined in local coordinate system of body 2 (direction from end of cylinder and inwards). They will be normalised in the input module.
NAXPTS input lines.
IAXPT AXPT

IAXPT: integer
: Axial point number 
AXPT: real
: Axial point, axial distance from end, \(\mathrm {[L]}\)
NAXPT * NPT input lines.
DIST FORCE DAMP

DIST: real
: Radial distance (transverse offset), \(\mathrm {[L]}\) 
FORCE: real
: Force in element, positive values signify attraction of the bodies, \(\mathrm {[F]}\) 
DAMP: real
: Damping coefficient, \([F[T/L]^{\mathrm {EXP}}]\)
Distances should be increasing and can not be negative, and each characteristic must have the same number of distances.
Force characteristics for each axial point, starting with point 1. At least one forcevalue must be zero.
Element failure, 1 input line
IFMOCO FTIME BTENS

IFMOCO: integer
: Failure mode of coupling element
= 0
: No failure 
= 1
: Failure by exceeding the tension after specified time. 
= 2
: Activated after specified time if Tens< BTENS


FTIME: real
: Earliest possible time of failure, \(\mathrm {[T]}\) 
BTENS: real
: Breaking strength, \(\mathrm {[F]}\)
Note! The coupling element breaks when both FTIME
and BTENS
are
exceeded
9. Fender coupling
1 input line
NPT IFRIC DYNFRIC STAFRIC STIFFRIC EXP INTPO VEMIN EHLA

NPT: integer
: Number of points in characteristics 
IFRIC: integer
: Fender model
= 1
: Fender point 
= 2
: Fender roller (zero friction in one direction)


DYNFRIC: real
: Dynamic friction coefficient, sliding 
STAFRIC: real
: Friction coefficient, when not sliding (stiction) 
STIFFRIC: real
: Shear stiffness associated with friction \(\mathrm {[F/L]}\) 
EXP: real
: Exponent of velocity in damping term 
INTPO: integer
: Interpolation method = 1,2,3 or 4
=1
: Linear force, linear damping. 
=2
: Linear force, parabolic damping. 
=3
: Parabolic force, linear damping. 
=4
: Parabolic force, parabolic damping.


VEMIN: real, default: 0
: Velocity limit for normal friction force (EXP=0
) 
EHLA: integer, default: 0
: HLA export flag for fender
= 0
: No export 
= 1
: HLA export

A fender roller is modeled as a point with zero friction in one specified direction. A spherical fender is a sphere with given diameter and omnidirectional friction.
Small velocities and EXP=0
can result in a large normal friction force
that suddenly changes sign. To avoid this the value EXP=1
will be used
when Abs(vel.)<VEMIN
and EXP<1
.
If EHLA = 1, 1 input line,HLA name of fender object,
CHCHLA

CHCHLA: character(120)
: Character string describing HLA coupling object name
Attachment point on body 1 in local body 1 coordinates (fender point), 1 input line.
CHBDY1 XF YF ZF

CHBDY1: character(8)
: Identificator of body 1 
XF: real
: Xcoordinate of fender point, \(\mathrm {[L]}\) 
YF: real
: Ycoordinate of fender point, \(\mathrm {[L]}\) 
ZF: real
: Zcoordinate of fender point, \(\mathrm {[L]}\)
Definition of fender plane and roller axis in Local body 2 coordinates, 1 input line.
CHBDY2 XP YP ZP XN YN ZN XA YA ZA

CHBDY2: character(8)
: Identificator of body 2 
XP: real
: Xcoordinate of point in the fender plane \(\mathrm {[L]}\) 
YP: real
: Y coordinate of point in the fender plane \(\mathrm {[L]}\) 
ZP: real
: Z coordinate of point in the fender plane \(\mathrm {[L]}\) 
XN: real
: Xcomp. of vector normal to surface \(\mathrm {[L]}\) 
YN: real
: Ycomp. of vector normal to surface \(\mathrm {[L]}\) 
ZN: real
: Zcomp. of vector normal to surface \(\mathrm {[L]}\) 
XA: real
: Xcomp. of vector parallel to fender rotation axis \(\mathrm {[L]}\)
Dummy for
IFRIC = 1


YA: real
: Ycomp. of vector parallel to fender rotation axis \(\mathrm {[L]}\)
Dummy for
IFRIC = 1


ZA: real
: Zcomp. of vector parallel to fender rotation axis \(\mathrm {[L]}\)
Dummy for
IFRIC = 1

For definition of fender plane dimensions, see the figure `Illustration of fender plane dimensions' below.
May be omitted in case of an unlimited fender plane is modeled, 1 input line
DV1X DV1Y DV1Z RL1 RL2
Vector defining direction no. 1 of fender plane,

DV1X: real
: Xcomponent of vector defining direction no. 1 
DV1Y: real
: Ycomponent of vector defining direction no. 1 
DV1Z: real
: Zcomponent of vector defining direction no. 1 
RL1: real
: Dimension of fender plane in direction 1 
RL2: real
: Dimension of fender plane in direction 2
Local body 2 coordinates are used. It is assumed that {XP,YP,ZP
} is
the centre point of the plane.
NPT input lines
DIST AFORCE DAMP

DIST: real
: Distance from fender point to fender plane \(\mathrm {[L]}\) 
AFORCE: real
: Axial fender force, normal to surface \(\mathrm {[F]}\) 
DAMP: real
: Damping coefficient \([F[T/L]^{\mathrm {EXP}}]\)
The characteristics can be given for monotonic increasing or decreasing
distances, DIST

Point fender: All
DIST ≤ 0

Spherical fender: All
DIST > 0

AFORCE = 0
at the largest distance
Compression force and damping are given as positive numbers
10. Bumper element coupling
1 input line
NPT INTPOM VEMIN EXPD EHLA

NPT: integer
: Number of points in bumper force characteristics 
INTPOM: integer, default: 1
: Interpolation method = 1,2,3 or 4
=1
: Linear force, linear damping. 
=2
: Linear force, parabolic damping. 
=3
: Parabolic force, linear damping. 
=4
: Parabolic force, parabolic damping.


VEMIN: real, default: 0
: Velocity limit for damping force (EXPD=0
) 
EXPD: real
: Exponent in damping 
EHLA: integer, default: 0
: HLA export flag for bumper
= 0
: No export 
= 1
: HLA export

Small velocities and EXPD=0
can result in a large damping force that
suddenly changes sign. To avoid this, the value EXPD=1
when
Abs(vel.)<VEMIN
and EXPD<1
.
If EHLA = 1, 1 input line, HLA name of bumper object
CHCHLA

CHCHLA: character(120)
: Character string describing HLA coupling object name
Coordinates of bumper line attached to body no. 1, 1 input line.
CHBDY1 XA1 YA1 ZA1 XA2 YA2 ZA2

CHBDY1: character(8)
: Identificator of body 1 
XA1: real
: Xcoordinate of bumper end 1, \(\mathrm {[L]}\) 
YA1: real
: Ycoordinate of bumper end 1, \(\mathrm {[L]}\) 
ZA1: real
: Zcoordinate of bumper end 1, \(\mathrm {[L]}\) 
XA2: real
: Xcoordinate of bumper end 2, \(\mathrm {[L]}\) 
YA2: real
: Ycoordinate of bumper end 2, \(\mathrm {[L]}\) 
ZA2: real
: Zcoordinate of bumper end 2, \(\mathrm {[L]}\)
Local body 1 coordinates
Coordinates of bumper line attached to body no. 2, 1 input line.
CHBDY2 XB1 YB1 ZB1 XB2 YB2 ZB2

CHBDY2: character(8)
: Identificator of body 2 
XB1: real
: Xcoordinate of bumper end 1, \(\mathrm {[L]}\) 
YB1: real
: Ycoordinate of bumper end 1, \(\mathrm {[L]}\) 
ZB1: real
: Zcoordinate of bumper end 1, \(\mathrm {[L]}\) 
XB2: real
: Xcoordinate of bumper end 2, \(\mathrm {[L]}\) 
YB2: real
: Ycoordinate of bumper end 2, \(\mathrm {[L]}\) 
ZB2: real
: Zcoordinate of bumper end 2, \(\mathrm {[L]}\)
Local body 2 coordinates
Contact force characteristics, NPT input lines
DIST AFORCE DAMP

DIST: real
: Distance between bumper centrelines \(\mathrm {[L]}\) 
AFORCE: real
: Bumper force, normal to elements \(\mathrm {[F]}\) 
DAMP: real
: Damping coefficient\([F(T/L)^{\mathrm {EXP}}]\)
The characteristics can be given for increasing or decreasing distances,
DIST
.
Compression force and damping are given as positive numbers.
11. Ratchet coupling
A ratchet coupling can either give compression or tension force, calculated from stiffness, damping and deviation from a reference length. A compression element will slide (and increase the reference length) when the compressive force becomes smaller than a specified minimum value. Similarly a tension element will slide and decrease the reference length if the tension passes the specified minimum tension.
1 input line
CHBDY1 XBDY1 YBDY1 ZBDY1

CHBDY1: character(8)
: Identifier for body 1 
XBDY1: real
: Xcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
YBDY1: real
: Ycoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
ZBDY1: real
: Zcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\).
1 input line
CHBDY2 XBDY2 YBDY2 ZBDY2

CHBDY2: character(8)
: Identifier for body 2 
XBDY2: real
: Xcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
YBDY2: real
: Ycoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\). 
ZBDY2: real
: Zcoordinate of coupling connection point in body fixed coordinate system, \(\mathrm {[L]}\).
1 input line
CHTYPE RFMIN RSTIFF TSTART RDAMP REXP VEMIN

CHTYPE: character(4)
:
TENSion
: Tension element 
COMPression
: Pressure element


RFMIN: real
: Static force in element \(\mathrm {[F]}\) 
RSTIFF: real
: Element stiffness \(\mathrm {[F/L]}\) 
TSTART: real
: Time when dynamics in element will be activated \(\mathrm {[T]}\) 
RDAMP: real
: Damping coefficient 
REXP: real
: Exponent in damping 
VEMIN: real, default: 0
: Velocity limit for damping force (EXPD=0
)
RFMIN
is minimum compression force if CHTYPE = COMP
RFMIN
is minimum tension if CHTYPE = TENS
, RFMIN
can be zero.
Small velocities and REXP=0
can result in a large damping force that
suddenly changes sign. To avoid this, SIMO
will use REXP=1
when
Abs(vel.)<VEMIN
and REXP<1
Element failure, 1 input line
IFAIL FTIME F_FAIL

IFAIL: integer
: Failure mode of coupling element
= 0
: no failure 
= 1
: failure by exceedance of force after specified time


FTIME: real
: Earliest possible time of failure, \(\mathrm {[T]}\) 
F_FAIL: real
: Maximum force, \(\mathrm {[F]}\)
The coupling element fails when both FTIME
and F_FAIL
are exceeded
12. Moment coupling
Direction of moment coupling, 1 input line
CHBDY1 DV1 DV2 DV3

CHBDY1: character(8)
: Identifier for body 1 
DV1: real
: Xcomponent of rotation axis, \(\mathrm {[L]}\) 
DV2: real
: Ycomponent of rotation axis, \(\mathrm {[L]}\) 
DV3: real
: Zcomponent of rotation axis, \(\mathrm {[L]}\)
The vector defines the direction of a moment in the body fixed
coordinate system of BODY1
This direction will be constant in the local system during a simulation.
At each time step the corresponding vector in the global system and in
BODY2
system will be calculated. At the initial position, the relative
rotation (about the moment axis) is defined to be zero. From one time
instant to the next during a simulation, the change in relative rotation
about the axis will be computed and added to total relative rotation.
This means that the calculated moment related to stiffness will be able
to handle rotations of more than 360 degrees (or less than 360deg.)
1 input line
MOM0 MOMK CPOS EXPOS CNEG EXNEG

MOM0: real
: Initial moment \(\mathrm {[FL]}\) 
MOMK: real
: Moment stiffness \([FL/\mathrm {rad}]\) 
CPOS: real
: Damping coefficient for positive rotation \([FL(s/\mathrm{rad})^{\mathrm{EXPOS}}\)] 
EXPOS: real
: Exponent in damping  positive rotation 
CNEG: real
: Damping coefficient for negative rotation \([FL(s/\mathrm{rad})^{\mathrm{EXNEG}}\)] 
EXNEG: real
: Exponent in damping  negative rotation
13. External coupling function data
The characteristics of a coupling element can be programmed as an external library, which is executed during a simulation. The required amount of input parameters depends on the external software. All parameters must be written, even if some are dummy (not used).
1 input line, path and filename of library containing the coupling
TXXCO

TXXCO: character(120)
: Character string giving path and filename
1 input line
NPCUR

NPCUR: integer > 0
: Number of points where current velocities shall be given to the external coupling library
1 input lines
CHBDY1 XBDY1 YBDY1 ZBDY1 EHLA

CHBDY1: character(8)
: Identificator for body 1 
XBDY1: real
: Xcoordinate of body attack point in its body fixed coordinate system, \(\mathrm {[L]}\) 
YBDY1: real
: Ycoordinate of body attack point in its body fixed coordinate system, \(\mathrm {[L]}\) 
ZBDY1: real
: Zcoordinate of body attack point in its body fixed coordinate system, \(\mathrm {[L]}\)
1 input line
CHBDY2 XBDY2 YBDY2 ZBDY2

CHBDY2: character(8)
: Identificator for body 2 
XBDY2: real
: Xcoordinate of body 2 attack point in its body fixed coordinate system, \(\mathrm {[L]}\) 
YBDY2: real
: Ycoordinate of body 2 attack point in its body fixed coordinate system, \(\mathrm {[L]}\) 
ZBDY2: real
: Zcoordinate of body 2 attack point in its body fixed coordinate system, \(\mathrm {[L]}\)
1 input line, may be dummy input if not used
NEL IACC EHLA

NEL: integer, default: 10
: Number of elements in the line 
IACC: integer, default: 0
: Flag for including acceleration of the line
= 0
: No acceleration of the line 
= 1
: Acceleration of the line included in the force calculations


EHLA: integer, default: 0
: HLA export flag for coupling
= 0
: No export 
= 1
: HLA export

The model for including line acceleration in the line force calculations is simplified.
If EHLA = 1, 1 input line, HLA name of external coupling object,
CHCHLA

CHCHLA: character(120)
: Character string describing HLA coupling object name
1 input line, may be dummy input if not used
DIA EMOD EMFACT RLEN FLEXC DAMPSW

DIA: real
: Segment diameter, \(\mathrm {[L]}\) 
EMOD: real
: Modulus of elasticity \(\mathrm {[F/L^2]}\) 
EMFAC: real
: Factor of elasticity
= 2
: For chains 
= 1
: For other segment types


RLEN: real
: Initial, unstretched line length, \(\mathrm {[L]}\) 
FLEXC: real, default: 0
: Connection flexibility, \(\mathrm {[L/F]}\) 
DAMPSW: real, default: 0
: Material damping \(\mathrm {[FT]}\). \(\mathrm {Force=dampsw*(\Delta L/\Delta t)/L}\)
Total stiffness, EA = EMOD
* EMFAC
* DIA
\(\mathrm {^2}\)
* \(\mathrm {\pi }\)/4.
1 input line, may be dummy input if not used
UWIA WATFAC CDN CDL

UWIA: real
: Unit weight in air, \(\mathrm {[F/L]}\) 
WATFAC: real
: The ratio of weight in water to weight in air, normally 0.81 for wire and 0.87 for chain 
CDN: real
: Transverse drag coefficient of the line 
CDL: real
: Longitudinal drag coefficient of the line . 
Drag force/length
= 0.5
*RHOW
*DIA
*CDN
*VN
\(\mathrm {^2\quad }\) Transverse 
Drag force/length
= 0.5
*RHOW
*DIA
*CDL
*VL
\(\mathrm {^2\quad }\) Longitudinal
Element failure, 1 input line
IFMOCO FTIME BTENS

IFMOCO: integer
: Failure mode of coupling element
= 0
: no failure 
= 1
: failure by exceedance of tension after specified time 
= 2
: Activated after specified time if Tens< BTENS


FTIME: real
: Earliest possible time of failure, \(\mathrm {[T]}\) 
BTENS: real
: Breaking strength, \(\mathrm {[F]}\)
The coupling element breaks when both FTIME
and BTENS
are exceeded