A closed form formula to predict the ultimate capacity of pitted mild steel plate under biaxial compression

Abstract

The aim of the present paper is to investigate the effects of pitting corrosion on the ultimate capacity of mild steel rectangular plates under biaxial compression, extending earlier results of uniaxially loaded plates. A series of non-linear FEM analysis of plates with partial depth corrosion pits are carried out, changing geometrical attributes of both pits and plates, i.e., the radius, depth and location of pits and the slenderness of plates. Simulation results show that volume loss dominates the degradation of the compressive capacity of pitted mild steel plates as well as loading ratio. Plate slenderness has considerable effect on biaxial interaction curve shape. A regression analysis of FEM results is conducted leading to a closed form formula able to predict the remaining strength of pitting corroded plates, where both volume loss and plate slenderness are taken into account. The proposed formula will facilitate a quick estimation of the remaining strength of pitting corroded plates during lifetime ship design phase which is relevant to maintenance decision-making of aging ship structures and components.