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 11 26 31 41 51 61 71
- --- -- ---- ------- ------ --------- --------- --------- --------- ---------
|X| | |ECAT|XXXXXXX| | | | | | |
- --- -- ---- ------- ------ --------- --------- --------- --------- ---------
| | | | | | | | |
| | | | | | | | |_(6) Unstretched Length
| | | | | | | | of Mooring Line Section
| | | | | | | |
| | | | | | | |_(5) Maximum Expected Tension at the
| | | | | | | the Attachment Point (E10.0)
| | | | | | | (default = 5.0E4 * mass/unit length)
| | | | | | |
| | | | | | |
| | | | | | |_(4) EA Value (E10.0)
| | | | | | (default = 5.0E6 * mass/unit length)
| | | | | |
| | | | | |_(3) Equivalent Cross-Sectional
| | | | | Area (F10.0)
| | | | |
| | | | |_(2) Mass/Unit Length (E10.0)
| | | |
| | | |_(1) Indicator of attachment point at which the pretension is defined
| | |
| | |_Compulsory Data Record Keyword (A4)
| |
| |_Optional User Identifier (A2)
|
|_Compulsory END on last data record in Data Category (A3)
(1) This data is optional. If the length of the mooring line (6) is not defined or its value is zero, this data gives an indicator of the attachment. For example, =1 means the pretension is defined at the first attachment point of the composite cable, =2 means the pretension is define at the second attachment.
(2) Mass per unit length of the section of the composite mooring line.
(3) 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).
(4) 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.
(5) The maximum expected tension is the highest value of tension that should used in the database created for this composite mooring line.
(6) The length of the composite mooring line section. Note that, in either the first section or last section of the composite cable's ECAT data record, this value could be undefined or set as zero to indicate that the pretension will be defined by the following NLIN or NLID data record together with Indicator of the pretension definition at the attachment point (1).
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.