The ECAT data record specifies the properties of each of the sections of the composite line. Although the data record title implies that only properties of elastic catenaries are expected, clump weights may be modeled by specifying a very large mass per unit length and a specification of unit length (Aqwa will not accept lengths less than 1). It is also possible to specify buoys and clump weights explicitly; see the BUOY data record (The BUOY/CLMP Data Records - Intermediate Buoys and Clump Weights).
2 5 7 31 41 51 61 71
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|X| | |ECAT|XXXXXXXXXXXXXX| | | | | |
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| | | | | | | |_(5) Length of Mooring Line
| | | | | | |
| | | | | | |_(4) Maximum Expected Tension at the
| | | | | | Attachment Point (E10.0)
| | | | | | (default = 5.0E4 * mass/unit length)
| | | | | |
| | | | | |_(3) EA Value (E10.0)
| | | | | (default = 5.0E6 * mass/unit length)
| | | | |
| | | | |_(2) Equivalent Cross-Sectional
| | | | Area (F10.0)
| | | |
| | | |_(1) Mass/Unit Length (E10.0)
| | |
| | |_Compulsory Data Record Keyword (A4)
| |
| |_Optional User Identifier (A2)
|
|_Compulsory END on last data record in Data Category (A3)
(1) Mass per unit length of the section of the composite mooring line.
(2) The equivalent cross sectional area of the mooring line. It is often more convenient, especially with wire lines, to specify this parameter so the buoyancy of the line may be calculated and subtracted from the structural weight to give the 'weight in water'. This parameter may also be specified as zero if the mass per unit length (1) is input as the mass of the line less the mass of the displaced water per unit length (this does not apply to the cases when cable dynamic analysis is required, for which a non-zero equivalent cross section area must be defined).
(3) The stiffness of the line is specified in terms of EA, where E is Youngs modulus and A is the cross sectional area of the line. The default value is chosen to give a typical value based on the mass/unit length. Clearly this may be in error if the mass per unit length specified (1) includes buoyancy effects.
(4) The maximum expected tension is the highest value of tension that should used in the database created for this composite mooring line.
(5) The length of the section of the composite mooring line. Note that values less than 1 are not accepted.
N.B. For a composite mooring line containing more than one ECAT data record, the definition of ECATs should start from the anchor point. If a composite mooring line links two structures the ECAT data records can start from either end, but the start must correspond to the second structure on the NLIN data record.
Limits on Mooring Systems
The maximum number of mooring combinations is 25.
The maximum number of mooring lines is 100.
The maximum number of nonlinear properties (i.e. POLY, SWIR, LE2D, COMP and ECAT data records) is 1000.
The maximum number of separate stiffness databases (i.e sets of data headed by COMP or LE2D data records) is 100.
The maximum number of ECAT data records in one COMP mooring line is 10.