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Problem with Probabilistic Damage Analysis - Maxsurf

Arnan Abdurrofi
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Hi,

This is my last year in university, I am a naval architecture student and currently working on project about how the width of the Ro-ro ship's void compartment affect their probabilistic damage (Attained index) using Maxsurf.
As far as i know, the dimension of the compartment and tank affect the number of Attained index. But the problem occured when i did the analysis of a ship with two different width of compartment, the result of Attained index remains the same.
I have attached some images of my compartmentation, loadcase and damage analysis settings. Do i missed something?

Thanks

All the three drafts result same A number

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  • +1 Offline

    Hi Arnan,

    I've seen this right at the end of my workday. I'll give you a more detailed response tomorrow. Here are some things to check in the meantime:

     - Your p.r.v and A values are the same. That means your vessel passed every single damage case.

     - You are only assessing single compartment damage (on the Global sheet), although this seems to be enough to get a pass.

    - Try exporting some of the loadcases into Deterministic damage stability to assess if they are behaving as you'd expect (Cases | Copy Prob. Damage Cases)

    I'll write more tomorrow

    James

    Answer Verified By: Arnan Abdurrofi 

Reply
  • +1 Offline

    Hi Arnan,

    I've seen this right at the end of my workday. I'll give you a more detailed response tomorrow. Here are some things to check in the meantime:

     - Your p.r.v and A values are the same. That means your vessel passed every single damage case.

     - You are only assessing single compartment damage (on the Global sheet), although this seems to be enough to get a pass.

    - Try exporting some of the loadcases into Deterministic damage stability to assess if they are behaving as you'd expect (Cases | Copy Prob. Damage Cases)

    I'll write more tomorrow

    James

    Answer Verified By: Arnan Abdurrofi 

Children
  • 0 Offline in reply to James Clarkson

    Hello James, thanks for the response. I have tried your advice to assess 2 and 3 compartments, And sure i have made the damage spaces too. The result of the analysis are as expected. The attained index has increased slightly with the change of compartments width. I uploaded the graph of the A number below

    So my first problem is solved, and thank to you for that. But what i doubt from the result are
    1. The result for the A number is very high. 0,98.. and more ____ Is it normal to have these number of Attained index (R number = 0,7) for a Ro-ro ship?
    2. The changes of the A number is very small ____ The former research about this topic shows that changes in the width of the wing tank of a Ro-ro ship results big difference in the A number. you can check the picture below

    [Slapnicar, 2009]

    I don't really sure with exporting prob. damage cases tab to damage case tab. Does it really affect the analysis? What is the difference between Prob Damage Case Tab and Damage Case Tab?

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