AQWA Stuff

Discussion in 'Software' started by CWTeebs, Oct 13, 2011.

  1. Nabeelarslan
    Joined: Jan 2012
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    Nabeelarslan Nabeel

    Dear CWTeebs

    I studied the aqwa wave manual which describes that it is a link between the aqwa line and asas which is a FEA software.It also states that aqwa wave has the ability to transfer pressure loadings to ANSYS APDL first converting it to asas file using anstoasas command and then running the aqwa wave in combination with files created by aqwa line.This will generate an output file which can be input to the ANSYS APDL using /INPUT command while in the solution processor.
    The problem I am facing is that how to run aqwa wave and generate an input file which has loadings from the aqwa line run.
    If you could help me about it I'll be so much obliged, and if you could manage the electronic copy of the tutorial please do mail me at nabeel_arslan@yahoo.com
    Regards
    Nabeel
     
  2. Nabeelarslan
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    Nabeelarslan Nabeel

    No dear I didn't mailed you about any topic all the discussion is over here.
     
  3. CWTeebs
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    CWTeebs AnomalyGenerator

    Yeah man I'll try to get you the electronic copy of the tutorial, sorry it took me so long to reply.
     
  4. Aproop
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    Aproop New Member

    Geometry problem

    Hi CWtweebs,

    I noticed that you have a REALLY regular mesh and very detailed surface especially at the bow region. Can you please explain how you did it, because the video is just postprocessing?

    PS: I usually build my models in GHS and for ease and time efficiency export them through Rhino as an IGES to DM. However, the geometry is very coarse. I have tried lofting the entire hull as one surface from the cross section profiles but the bow and stern bulb areas give me problems.

    PPS: Have you also worked with mooring and line section definitons. Would it be possible to put up a little more than results on the forum?

    Thanks,
    Aproop
     
  5. CWTeebs
    Joined: Apr 2011
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    CWTeebs AnomalyGenerator

    Hey nabersaan I posted a document that describes how to export AQWA data at this thread:

    http://www.boatdesign.net/forums/hydrodynamics-aerodynamics/fluid-structure-interaction-41995.html

    AProop: It took a long time to get this mesh to work, and it's still not perfect. I basically followed the same steps as you did, except the original model was made using Multisurf. I modified the model in rhino and exported as an iges into DM. The only thing "special" I did was to create a local size definition for the bow diffracting panels, such that it would get more densely tesselated in the bulbous bow region.

    With respect to your other question what else would you like me to post? It sounds like you just wanted a working mooring example?
     
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  6. Aproop
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    Aproop New Member

    CWT,

    Before I begin, a disclaimer, this is going to be a long post!

    It is still a pretty good and regular-looking mesh, hats off to you! One thing in connection to the video you'd posted though, I can't seem to save the animation file for a cyclic wave using the save button (the file length comes to 0 seconds). Is there something else you have to do to save the animation? I remember vaguely when I was using ANSYS CFX that there was a menu for saving the animation file.

    I guess I need a quick way to build the model rather than spend a lot of time on refining the geometry. There is a feature within the AQWA DM interface that can read in offset files in the form of text, similar to a .lin file but slightly different in the formatting. Even though I have my offset points, getting down to formatting the file in the same way is a bit of a bummer. Have you explored this option, and met with any success if so?

    What I meant regarding the mooring was that I need to find a way to convert a technical description/proposal that covers the lines and connections to a corresponding model in AQWA. I am a Naval Architect and have only begun venturing into this area of mooring for FPUs. The description contains a Top Chain, Excursion Limiter, Ground Chain, Drag Anchor and so on. AQWA gives multiple options like cables & catenary data (which one do I use for what?), and now we have in addition to fixed points, joints, fenders, and if I remember reading correctly, articulation points somewhere. I understand the degrees of freedom will vary with each type, but how much of a difference will that make to the solution, considering the older versions of AQWA didn't come with these varied options?

    One more thing, I ran a motion response calculation for the free floating ship and tried transferring it to a hydrodynamic time response, but when I tried solving there I got an error stating "Non-existent structure" and "Structure number zero (fixed poistion) not allowed on first node".

    PS: I have never explored anything that goes beyond the few demonstrations of geometry creation and pressure plots in AGS. Is there some comprehendible source (my which I mean anything but the AQWA help files) that show how to use aqwa using the non workbench interface? I have seen on one of your posts that you've mentioned the more powerful interface in the general AQWA module. You'd mentioned some notes that you had, would it be possible for you to share them with me?

    Thanks!
    Aproop
     
  7. Aproop
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    Aproop New Member

    PS: Forgot to add, an example would also help!

    Also for the mesh sizing, I guess you used a seperate surface altogether for the bow?

    Aproop
     
  8. khabiran
    Joined: Aug 2010
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    khabiran Junior Member

    For using soft model without any inquietude, It's good to transfer your model from rhnio to DM with SAT format. It is the best format.
     
  9. saeideros
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    saeideros New Member

    Hi CWTeebs
    You solve my problem. Thank you
     
  10. khabiran
    Joined: Aug 2010
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    khabiran Junior Member

    AQWA limit size

    Hi every one . Recently I try to analysis a mat with follow lengths(B=60, L=300 T=2, D=0.5 all in m) and meshing size was 0.5m. But my solve was aborted.
    Try to small size, in scale 1/10 without any error.
    Is there any limit in size?

    BR
     
  11. saeideros
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    saeideros New Member

    Hi,

    Maximum number of element is limited to 22000.
     
  12. Buddychichi
    Joined: May 2012
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    Buddychichi Junior Member

    Hello everyone,
    I am a new user with ANSYS workbench. Though within a short period I have managed to do loads of reading and experimenting on the software; however, I am having problem with modeling the tether of a tension leg platform and doing the required analysis. Thus my question entails
    1. How to model the tether system so I can effectively analyze the system behaviour and the tether? I can see connection in the workbench with the model and anchor to the sea bed. I have managed to connect it that way but I don’t know how to include the initial tension in the tendon to relate to the entire behaviour of the system.
    2. Can I achieve most TLP analysis requirement using ansys workbench only or do I need to use the aqwa suite in some of the analysis and how? I am a new user and I Lack some basics which means that I don’t know the difference between workbench aqwa and capabilities with aqwa suite. The manual and information I See are not explicit enough.
    I require some of this analysis for the project work I am doing on tension leg platform design so I can investigate the TLP behaviour and analyse/design the failure modes (fatigue and ultimate limit state).
    Cwteebs pls. I am stuck
     
  13. CWTeebs
    Joined: Apr 2011
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    CWTeebs AnomalyGenerator

    You can to accomplish this in Workbench using a drift analysis. You need to calculate the hydrodynamic database using AQWA-LINE that calculates the full quadratic transfer functions and near-field solution for aqwa-drift. For the TLP you'll need to use the sum-frequency effects due to the low waterplane area and high volume of the TLP.

    I can't otherwise tell what you might be doing wrong without seeing your workspace.

    -CWTeebs
     
  14. Buddychichi
    Joined: May 2012
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    Buddychichi Junior Member

    CWTeebs

    Hi CWTeebs
    Thanks very much for the quick response and the tips. I appreciate it very much. This note is just to acknowledge you reply. Thank you.

    Pardon my ignorance, but I have been looking for a place on the computer program called aqwa line, aqwa Librium, aqwa-fer etc. or deck 1 deck 2 etc. I can’t find. it sounds abstract as regards to the software in front of me. #

    Pls, how can I make you see what I am doing? I don’t mind email you the model or whatever folder associated with it.

    Running hydrostatics in workbench is that aqwa line?
    Thank you
     

  15. saeideros
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    saeideros New Member

    Hi Buddychichi

    You can find aqwa line, aqwa Librium, aqwa-fer and etc here.
    Start Menu>All Programs>ANSYS XX.X>AQWA>AQWAGSXX.X
    Menu bar> RUN>

    And yes,Running hydrostatics in workbench is aqwa line.

    But about DECKs. It's my question too.
    CWTeebs, help us please.
     
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