Influence of local corrosion on membrane residual stress in welded I-section steel

Corrosion in welded I-section steel structures would disrupt the self-equilibrium of cross-sectional stresses, rendering them prone to failure under the combined action of loading stresses, residual stresses, and local corrosion. To clarify the influence of local corrosion on cross-sectional residual stresses, six welded I-section steel specimens with simulated corrosion damage were designed and tested, with variations in corrosion location, depth, and dimension. Electrochemical accelerated corrosion tests were used to induce non-uniform geometric damage, and the resulting corrosion morphology was evaluated using three-dimensional scanning technology. Sectioning method was then employed to measure the membrane residual stress distribution. The measured results indicated that local corrosion had a minimal effect on the overall distribution pattern of the residual stress, while significantly altering the residual stress magnitudes within the corroded region. The maximum compressive residual stress of the most seriously corroded specimen T1–150-3 increased by 78.7 %. In addition, the 3D transient thermomechanical finite element (FE) models were established to simulate the progressive welding and corrosion. A parametric analysis was performed to quantify the influence of corrosion characteristics and geometric parameters on residual stress distribution and magnitude. Finally, the equivalent force coefficient and the amplification coefficient were proposed and incorporated into the existing ECCS model to predict the membrane residual stress distribution in welded I-section steel with local corrosion. The proposed distribution model exhibited high accuracy with experimental and numerical results, and the maximum deviation in compressive residual stress was within 10 %.