Plastic strain localization behavior of corroded steel plate under tensile loading

Recent studies have shown that ductility of steel members under tension can be reduced due to the presence of corrosion surface roughness. This reduction in ductility of corroded steel members is caused by the stress concentration and plastic strain localization phenomena, resulting from the unevenness of the thickness. This paper presents results from the investigation on ductility reduction of corroded steel plates under tensile loading for different degrees of corrosion surface roughness, and finally proposes a relationship between the corrosion surface roughness and a degree of plastic strain localization. To identify a region of strain localization, the digital image correlation method is used on the images taken during tensile tests of corroded steel specimens, and area of large strain is identified at the two different times during the tensile test: maximum load and just before fracture. As a result of this study, it is found that the reduction in ductility of corroded steel under tension can be explained quantitatively by the reduction of area of large plastic strain region and that the reduction of area of large plastic strain region can be estimated by surface roughness parameters.