Abstract
The purpose of this research project is to establish a method of evaluating the effect of pitting corrosion with a circular cone shape on local strength of hold frames of bulk carriers. In the present study, an empirical formula is proposed based on the tensile test results conducted in the previous study. In the formula, tensile strength reduction due to pitting corrosion is expressed as a function of DOP (degree of pitting intensity), pit diameter and original thickness of pitted plates. It has been shown that tensile strength of relatively small plates with pitting can be well predicted by the formula. In order to check the applicability of the formula to wide plates, a series of tensile test with wide specimens having artificial pits has been performed. It has been found that when diameter of all the pits is the same, prediction results of the tensile strength of wide specimens with artificial pits are conservative, and when pits with different diameter coexist, prediction of the tensile strength using average pit diameter give a little optimistic (non-conservative) results.
