Uniaxial behaviour and corrosion-welding-based constitutive model of marine structural steel

Abstract

To address the coupled damage from corrosion and welding on the performance of marine structures in a rationally macroscopic way, an experimental attempt is conducted and to propose a generalized corrosion-welding-based material model for various corrosion and welding scenarios. The tested D36 steel specimens have welding seams with three angles and six corrosion degrees generated by the accelerated electrochemical corrosion method. The uniaxial behaviour of the specimens is studied from the aspects of failure process, stress vs. strain curves and strain distributions. All the performance parameters, as well as elastic segment, yield plateau and nonlinear strain hardening segment, can be affected by both corrosion degree and welding angle. Welding can cause increased yield strength and ultimate strength, but at the cost of yield plateau and toughness. Both welding and corrosion can affect the strain development in two directions. The proposed corrosion-welding-based model that consists of a linear segment and a nonlinear strain-hardening segment with the calibrated parameters by the test data can desirably describe the coupled damage. It is believed to be able to extend the fiber model for the structure-level performance assessment of corroded-welded steel jacket offshore platforms.