Ansys Learning Forum Forums Installation and Licensing Ansys Products Catenary mooring input “Maximum Expected Tension” & suspended length, Ansys Aqwa Reply To: Catenary mooring input “Maximum Expected Tension” & suspended length, Ansys Aqwa

Shuangxing Du
Ansys Employee

Please read Aqwa User's Manual, Section 5.8.1.4.

For nonlinear catenary cables attached between a fixed point and a structure (Connectivity set to Fixed Point to Structure), internally Aqwa converts them to the multi-dimensional load/extension databases.  The range of the possible fairlead locations of the cable in the database is determined by Negative dZ Range of Expected Connection Point Vertical Motion (measured from the lowest anticipated database point to the connection point in the definition position) and Positive dZ Range of Expected Connection Point Vertical Motion (measured from the connection point in the definition position to the highest anticipated database point) along with the slack and maximum expected tension positions (including the effects of the global or cable-specific seabed slope). This area is then divided up to form a database of cable end positions and corresponding tensions which is used in the analysis. It is recommended that the full size of this grid is used, of 600 points, which is formed by the multiplication of Number of Vertical Partitions and Number of X Coordinates.

If you have known the maximum tension at the fairlead of the nonlinear catenary mooring for the structure under the analysed environment conditions, you can directly input it as the maximum expected tension. If you do not know this value, it could be the tension value at the fairlead when the cable may be broken if the actual tension at this point exceeds that value.