|Title: Progressive Flooding Assessment of the Intermediate Damage Cases as an Extension of a Monte-Carlo based Damage Stability Method|
|Written by: Hendrik Dankowski, Stefan Krüger|
|in: PRADS, Korea 2013|
Abstract: The computation of intermediate flooding stages for current damage stability rules is a very complex and time consuming task for the design engineer and usually only performed manually for certain critical cases and stages. A progressive flooding method is presented in this paper, which computes the flux between the compartments based on the Bernoulli equation. Large and partly flooded openings are taken into account as well as optional air compression and flooding through completely filled rooms. The method is validated with the standard benchmark model test recommended by the ITTC. Especially for multi-compartment damage combinations, the correct treatment of possible critical intermediate stages of flooding is unclear and only briefly described in the current SOLAS 2009 regulations. The method presented here uses a typical damage opening based on the generated damage cubes by a Monte Carlo simulation to perform a direct progressive flooding assessment for each critical intermediate case. This method has the advantage to remove the limitation of typical three to four discrete intermediate stages of flooding, that are usually assumed. Instead, it allows to investigate each intermediate damage case in the time domain to gain a more detailed view on the severity of the flooding process and the vulnerability of the ship with regard to flooding of the watertight integrity after damage. The generation of the damage cases and the required openings is completely automated by chopping the section based hydrostatic model of the hull and the compartments with an appropriate damage cube. A robust and fast algorithm taking into account complex compartment geometries including negative sub-spaces will be presented. The combination of flooding calculations with a Monte Carlo method extends the classical damage stability calculations to the time domain, which allows a more accurate estimation of the overall safety level of a ship to withstand damage.