Numéro : 2013 - Year : 1986
Analysis of damages on a 160000 dwt ore/oil ship.
R.TEDESCHI, Professor, Department of Naval Architecture , Geneva University
D.CERVETTO, Research Engineer
F. ZILIOTTO, Senior Research Engineer Registro Italiano Navale
This paper deals with the analysis of the damages detected on the transverse structures of the lateral tanks of a 160.000 DWT ORE/OIL ship. These damages were the outcome of an extensive corrosion, spread all over these structures, and enhanced in the area where the stress level was increased by local structural discontinuities.
First, we discussed the operating conditions of the ship during her whole life and the level and distribution of the corrosion in order to clarify the reasons why the corrosion was so high.
On the basis of the above considerations, finite element calculations were carried out to evaluate the stress level in the most affected areas.
These analyses showed that the ship was tough enough. Nevertheless, in some typical and recurring details, a little higher stress level caused by stress concentrations could have enhanced the corrosion. Moreover, after initial failure, redistribution of loads should have occurred, causing new stress concentration points.
Some modifications required to restore or improve, where necessary, the original strength of the ship are also discussed.