Time domain analysis of Pile-moored Barge

Dear Sir,

Please let me describe my problem: an offshore barge is permanently moored along the river bank by using 3 piles of which the bottom ends are fixed on the seabed, the top end are connected to the barge, and what I want to know is the reaction force at the 3 Barge-Pile connections under a certain circumstance. 

3 bodies are modeled in the dat.file, one is barge itself, second is three piles, and the last is seabed which is intended to show as a picture purpose, no force attracted. And two types of GSPR connector are applied to barge-pile connection and pile-seabed connection respectively, and I use REST(restraint) to fix the 3 points of the seabed body which are also connected to the bottom of the 3 piles by using the GSPRs. Then I thought the entire model had be well restrained. But When I check the log file, the reaction force of all the connectors are 0, even when I see the graphic animation, the whole model is moving along as the sea(wave) is approaching.

I have no idea  where the problem takes place and I have tried dozens of time, still fail to solve to the problem. So I come here and beg somebody to give me hand and help out the jam.

Thanks and Regards

Xintong

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  • Hi,

    The manual says: "A restraint is an element which acts like a con-
    nector during a stress analysis, but does not act during a simulation. Basically,
    restraints are of limited use." Maybe you should try using CONNECTOR instead?

    Also, a PILE class would perhaps give you more realistic conditions at the seabed, if relevant.

    Regards,
    Lars Rune
  • Thanks for your answer, as you said the Class PILE could help to model the realistic seabed condition, later I will apply this class to model the pile once we obtain the seabed soil data. I just found out the way to "fix" the whole model in the animation, that is to model the seabed with body ground.
    Unfortunately, examine from the output file, Force acting on Barge, I noticed that the barge has big unbelievable difference between self weight and buoyancy after the hydrodynamic pressure database and &environment had been input(analysed), the self weight is almost 5 times the buoyancy, which results in one large inertia force existing. And before the MOSES read g_pressure and &environment, I am sure barge and Pile are in equilibrium condition. I have no idea why it happened like this, can you give me some hint, I would be very grateful.
  • Sorry, no idea, but make sure that barge is in floating equilbrium by issuing &equi before you attach the springs between barge and piles.
  • Hi Mr.Lars, I really appreciate your kind reply to my query. To be honest, I am a new user of MOSES, but I am really attracted by its powerful analytical ability of offshore engineering solution. It seems like you are also expert in MOSES, so can you leave me your private email address so that I can have a further consultation from you. My current project is related to an offshore power barge, but it is a little new to me, so can you just leave me a chance to learn something from you.
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  • Hi Mr.Lars, I really appreciate your kind reply to my query. To be honest, I am a new user of MOSES, but I am really attracted by its powerful analytical ability of offshore engineering solution. It seems like you are also expert in MOSES, so can you leave me your private email address so that I can have a further consultation from you. My current project is related to an offshore power barge, but it is a little new to me, so can you just leave me a chance to learn something from you.
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