Effect of Corrosion on Static Strength of Hull Structural Members (4th Report)

Abstract

The purpose of this study is to investigate the effect of pitting corrosion on local strength of hold frames of bulk carriers. In the present study, a series of 4-point bend tests with structural models which consist of web, shell and face plates has been conducted. Artificial pitting was made on the web plate. In these tests, two equal concentrated loads has been applied at the one third points of simply supported models so that compression load would act on the face plate. In this testing condition, lateral-distortional buckling occurred before ultimate load was reached and local buckling of the face plate was observed after the ultimate load. It has been revealed that the effect of pitting on the web plate on lateral-distortional buckling load was small but ultimate load decreases with the increase of area ratio of pitting. As a result of FE-Analysis, the ultimate load of the structural models where pitting prevailed uniformly on the web plates was found to be almost the same as that of the structural models where the web plates have uniform corrosion corresponding to the average thickness loss.