Multibuoy mooring

Hello to everyone,
I'm doing my grad work on MBM buoys structural simulation. I'm using SoliWorks and Asys Aqwa and Mechanical. I know how to draw in SW, but almost nothing about Aqwa.

Here I'll be reporting my advances and some questions that if you can help me solve I'd be really gratefull. Wish me luck

The first thing I'm doing is learning how to do a hidrostatyc analysis on Aqwa. I'm using this tutorial: https://www.youtube.com/watch?v=47xmiEi9FQY but the sound is bad and it's kind of outdated.

Do you know any other tutorials I could use?? The method used seems quite complex (directly editing text), could you recomend me any other method??

 

I've managed to do the tutorial! I found many people needed help finishing it, so I'll upload the files.

Also I found other Aqwa tutorials that I'll upload soon!

Pronto I will be doing some progress on wind, current and wave force calculations (by hand using some manuals). Do you know any software, free if able, to do this calculations too?? It would be helpfull to compare results. Thank you!!

 

So it seems I can't send links to official tutorials, welp I'll upload the nonofficial tutorials I have (thanks to kristeen) and the Youtube tutorial (thanks Utkarsh Ramayan) tutorial files:

YoutTube Tutorial (https://www.youtube.com/watch?v=sYjND8YnFp0 by Utkarsh Ramayan, files by me): https://mega.nz/#!99IlCLpL!6sMbll7aSILtqcDNCKdfb4iSpxtNbgsOwaSZwQLWrwY

Nonofficial Tutorials (by kristeen): https://mega.nz/#!l5wEXQqQ!QUjYzB352G1G5XRUzZcRGl9M-cmi_41U8bcUqsiSDA0

Now I'm looking how to do a buoyancy analysis to determine the waterline, do you know how to do it in Ansys (machanical, cfd, aqwa, etc.)?? Thank you!

 

Hello, good news, so far I've managed to:
-Create the geometry of the ship and buoys (using SolidWorks and importing in .igs format),
-Do a hidrostatic analysis of the model,
-Create the conection points between bouys and ship and create the fixed points to the sea bed,
-Define (non-linear) mooring lines, sinkers (clump weights), and (catenary) chains,
-Apply wind, current and regular wave data on the model,

Now I'm doing the time response analysis.

Aqwa solves succesfuly if I use a timestep of 0.005s and a duration of 10s.

When using a 0.005s timestep and a 100s duration this error appears an it aborts the solution:
-CABIN4:CONV. FAILED STAGE#1 - DDNMAX=23.0138 LINE#8
-CABIN4:CONV. FAILED STAGE#1 - DDNMAX=24.1650 LINE#8

When using a 0.01s timestep and a 10s duration this error appears an it aborts the solution:
-YOUR TIME STEP IS PROBABLY TOO BIG. For this time-step the natural periods of the system troughout the analysis MUST BE GREATER THAN 0.10 seconds. i.e. Frecuency LESS THAN 62.832 rad/sec.

Do you know how to fix any of this errors? The first one seems related to some cable property? The second one to some limitation in the analysis settings? Thank you!

 

Well it turns out I defined the point mass location of the buoys using the local coordinate system of the buoys instead of the global cs. I still get the errors sometimes but everything seems to be working better now.

-Now thats fixed, but I'm still not sure if the moments of inertia should be defined using the buoys' local axis or the global cs. Do you know?

-Also does anyone know which value should go on Postive and Negative dz range? I have 1 and 0, and it dosen't seem to affect results

-Another data I'm missing is the stiffness per metter,stiffnes coeficents and breaking load of fiber mooring ropes and anchoring chains of the VLCC, does anyone knows where I can find some references?

Thank you!!

 

Hello,(this is related to post on oct:24/2016 by gust on multibuoy mooring)
I am getting same errors in mooring .what did you do to rectify it?
Thank you.