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Brodogradnja : An International Journal of Naval Architecture and Ocean Engineering for Research and Development, Vol. 68 No. 4, 2017.

Original scientific paper

https://doi.org/10.21278/brod68404

AN APPROACH TO THE PROBABILISTIC CORROSION RATE ESTIMATION MODEL FOR INNER BOTTOM PLATES OF BULK CARRIERS

Špiro Ivošević orcid id orcid.org/0000-0001-6670-4770 ; University of Montenegro , Maritime Faculty Kotor, Dobrota 36, Kotor, Montenegro
Romeo Meštrović ; University of Montenegro , Maritime Faculty Kotor, Dobrota 36, Kotor, Montenegro
Nataša Kovač ; University of Montenegro , Maritime Faculty Kotor, Dobrota 36, Kotor, Montenegro

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Abstract

This paper gives an approach to the probabilistic corrosion rate estimation model for inner bottom plates of bulk carriers. Firstly, by using the data from thickness measurements for inner bottom plates for considered 25 bulk carriers, the related best fitted linear model for the corrosion wastage is obtained as a function of ship’s age. In this model it is assumed that life of coating is 4 years. The obtained related corrosion rate is equal to mm/year. Notice that the obtained linear model is a particular case of a power model proposed in some earlier investigations.
In view of the fact that the corrosion rate of ship hull structures is influenced by many factors, many of an uncertain nature, in recent studies several authors investigated a probabilistic model as more appropriate to describe the expected corrosion. Motivated by these investigations, and using 2926 thickness measurements for corrosion wastage of inner bottom plates of considered 38 special ships surveys, this paper examines the cumulative density function for the corrosion rate involved in the mentioned linear model, and considered here as a continuous random variable. The obtained statistical, numerical and graphical results show that the logistic distribution or normal distribution would be well appropriate for the probabilistic corrosion rate estimation model for inner bottom plates of bulk carriers. It is believed that this fact will be confirmed with greater statistical reliability in our future investigations including many more data collected on the considered corrosion.

Keywords

bulk carrier; fuel oil tanks; ship hull structure members; inner bottom plates; corrosion; probabilistic corrosion rate estimation model; normal distribution; logistic distribution

Hrčak ID:

186015

URI

https://hrcak.srce.hr/186015

Publication date:

31.12.2017.

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