THE NULL EFFECT OF CROSS SECTIONS OTHER THAN THE MAXIMUM PITTED CROSS SECTION ON STRENGTH REDUCTION OF AGED MARINE PLATES SUBJECTED TO UNIAXIAL TENSILE LOADING

Abstract

It is of essential importance to predict the strength reduction due to pitting corrosion for a proper condition assessment of aged ships. The crucial location of maximum pitting as well as the heavy unevenness of the metal surface creates difficulties for the surveyors to perform the survey. Empirical formula based on statistical data can assess the strength reduction due to pitting on the basis of damage intensity where the strength reduction is only a function of maximum pitted cross section. In this study, the formula is established again by nullifying the effect of other cross sections on the strength reduction except the maximum pitted cross section. This null effect of less pitted cross sections will increase the surveyors’ confidence to concentrate only on the maximum pitted cross section. A series of finite element analysis is carried out where MSC NASTRAN nonlinear implicit analysis code has been used in large deformation analysis of two different pitted marine steel rectangular plate samples. The pitting patterns of different intensity used in this study were generated by other researchers using a probabilistic corrosion model.