Anchor Uplift

edited September 25 in Structures

When using ANSYS AQWA to complete a hydrodynamic time response I have multiple instances where I have a long length of mooring in contact with the seabed (LL>>0 meters), but there is an anchor uplift force (AL) that is greater than 0. How is this possible? I have assumed that uplift is in the vertical direction, but this could be wrong.

Any help would be greatly appreciated!


  • Hello,

    I'm posting this response on behalf of my colleague - @sxdu . Here is the response.

    Please check if the mooring line is modelled by the dynamic cable. As shown in Figure 9.8 in Aqwa Theory manual, in the dynamic cable analysis, the cable is discretized by number of elements,  the seabed is modelled by the mud layer with a thickness of 2 meters above the seabed. The mud springs are linked the mud line and the nodes of the cable elements if they are beneath the mud line. It is assumed that the cable element is touched down seabed if its nodes' locations are not higher than 0.56m from seabed. Due to the mud spring action on the first element starting from anchor, the uplift force on anchor may not be zero, but should be small if the cable's laid length is greater than zero.

    I hope this helps.



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