Mooring line tension error in AQWA ANSYS

Discussion in 'Software' started by Brany, Apr 21, 2017.

  1. Brany
    Joined: Mar 2017
    Posts: 2
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: Thailand

    Brany New Member

    Hello. I have been using AQWA to find the motions of an internal turret fpso. I am using Worbench. I am testing two cases with 500m and 1000m water depth ,different mooring system for each. When I run the analysis of HTR (hydrodynamic time response) with irregular wave, the solve aborted with the error message as in the screenshot attached below. The error says: CCOMDB: ERROR OCCURS WHEN CREATING COMPOSITE CABLE DATABASE FOR LINE#1
    and !CCOMIL - COMP D/B - MAXIMUM TENSION TOO SMALL I.E. < 1.1*MINIMUM TENSION

    error msg.png

    That happened in both the 500 m and 1000 m cases.
    I tried changing the configuration of the mooring system in order to get higher pretension but the error still occurs. The mooring design and the configuration are attached below. Have you ever encountered this before? I wanna know what I'm doing wrong. View attachment 500 View attachment 1000
     

    Attached Files:

  2. oataru
    Joined: Nov 2010
    Posts: 8
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: Thailand

    oataru Junior Member

    Hi Brany,

    I'm from the same country.
    Didn't you notice that your maximum tension input was impractically so small for such scale of mooring problem?
    Check your cable properties again.
     
  3. Chiemela Victor
    Joined: Apr 2019
    Posts: 6
    Likes: 0, Points: 1
    Location: London

    Chiemela Victor Junior Member

    It is from the tension input for the mooring lines. It is very impractical to have such for your mooring lines. When you run the ANSYS AQWA solver, it will hit an error: CCOMDB: ERROR OCCURS WHEN CREATING COMPOSITE CABLE DATABASE FOR LINE#1
    and !CCOMIL - COMP D/B - MAXIMUM TENSION TOO SMALL I.E. < 1.1*MINIMUM TENSION

    This is because of the Maximum tension too small. It should not be. Check the cable properties. Ropes have flexible properties, but chains and loose links have a different flexible behavior as they are more rigid but held together by contacts in the link.

    Check it again, and let me know how it goes, if not sorted. I use ANSYS AQWA and Orcaflex for my designs and analysis.
    For further reference, you can check out my papers on:
    Strength of submarine hoses in Chinese-lantern configuration from hydrodynamic loads on CALM buoy
    hose https://www.sciencedirect.com/science/article/pii/S0029801818314550

    Composite risers for deep waters using a numerical modelling approach
    https://www.sciencedirect.com/science/article/pii/S0263822318302642
     

    Attached Files:


  4. Hahazy
    Joined: Jun 2019
    Posts: 1
    Likes: 0, Points: 1
    Location: China

    Hahazy New Member

    Hello, I have met the same problem (CCOMDP and CCOMDB ) in Hydrodynamic Responese analysis ( stability analysis ).My model is a multi-floating body ,they link to each other by nonlinear caternary(HMPE), as their distance is very small (0.5m),I define the cable in 1 meter ,so the cable is slack, but the initial tension is bigger than maximum tension´╝ł4000kN) that I define in caternary section. Actually, I doubt and want to know if you do the same pre-processing that define the wind/current force coefficient,connection point and connection cable( nonlinear catenary) before you solve the Hydrodynamic Diffraction and Hydrodynamic Response in workbench. I do not know pre-processing like this if have an effect on the next analysis in Hydrodynamic Diffraction and Hydrodynamics Response. Although the Hydrodynamic Diffraction run the *dat file in state 1-3 which do not contain deck 14 of mooring, and I examine the *dat file that deck 14 was none actually.
     
    Last edited: Jun 14, 2019
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