This data record inputs parameters which are required for the iteration solution during the large angle stability calculation. The iteration parameters find the large angle position which is balanced in a heave and pitch direction in the rotation axis coordinate system. The progression towards this equilibrium state can also be controlled via the input of this data record. If you do not specify particular convergence limits and the likes, the program uses default values.
Note: A rotation axis coordinate system is a coordinate system with a positive X-axis along the rotation axis direction, a positive Z-axis along the global positive Z-axis direction, and a Y-axis following the right-hand rule.
2 5 7 11 16 21 31 41 51 61
- --- -- ---- ----- ----- ---------- ---------- ---------- ---------- --------------------
|X| | |LALM|XXXXX| | | | | |
- --- ------------- ----- ---------- ---------- ---------- ---------- --------------------
| | | | | | |
| | | | | | |_(5)Maximum Errors for Pitch
| | | | | | for System to be Considered
| | | | | | in Large Angle Stability
| | | | | | (E10.0)
| | | | | |
| | | | | |_(4)Maximum Errors for Heave
| | | | | for System to be Considered
| | | | | in Large Angle Stability (E10.0)
| | | | |
| | | | |_(3)Maximum Pitch Movements allowed per Iteration (E10.0)
| | | |
| | | |_(2)Maximum Heave Movements allowed per Iteration (E10.0)
| | |
| | |_(1)Maximum Number of Iterations (I5)
| |
| |_Compulsory Data Record Keyword (A4)
|
|_Optional User Identifier (A2) (1) If you do not specify the maximum number of iterations, the default value of 100 is used.
(2) is the maximum heave movements allowed per iteration with respect to the rotation axis coordinate system. The default value is 0.5 (G=9.81).
(3) is the maximum pitch movements allowed per iteration with respect to the rotation axis coordinate system. The input must be in degrees. The default is 0.573 degrees.
(4) refers to the maximum errors allowed in the final balanced position in the heave direction with respect to the rotation axis coordinate system. This means if the calculated heave movement is less than this, the structure is assumed to be balanced in the heave direction. The default value is 0.02 (G=9.81).
(5) refers to the maximum errors allowed in the final balanced position in the pitch direction with respect to the rotation axis coordinate system. This means if the calculated pitch movement is less than this, the structure is assumed to be balanced in the pitch direction. The input must be in degrees. The default value is 0.057 degrees.
To take into account the varying unit systems, Aqwa multiplies the default translation values only by G/9.81, where G is the value of gravity input in Data Category 5. These defaults are overwritten by any values input in this data record, but Aqwa does not apply any additional factors, which means the value on the data record is the value that is used.