In this paper, salt spray tests were firstly conducted for Q690 high strength steel plates. After the corrosion tests, the corrosion products were removed and the weight loss ratio was obtained. Then the topographies of the rough surfaces were scanned by a 3D surface profiler, and the 3D coordinates of the corroded surfaces were exported. Based on the data, the topographic feature parameters were determined, the uniform corrosion depth was calculated, and the extreme value analysis was conducted for the pitting corrosion depth to investigate its stochastic features. Finally, the corroded surfaces were restored and the finite element models of the scanned segments were established, which were validated by the experimental results and used to conduct the stress concentration analysis. The experimental results showed that the topographic feature parameters were linearly related to the weight loss ratio, and the maximum pitting depth conformed to the Frechat distribution. By conducting finite element analysis, it was concluded that under the uniaxial tensile load, the corroded steel plate showed an obvious stress concentration effect and most nodes were in a multiaxial stress state. In terms of the characteristic loads, both uniform and pitting corrosion induced the yield load and the ultimate load degradation. Regarding the uniform corrosion component, the loss percentage of the characteristic load was equal to the corresponding weight loss ratio. However, the loss percentages of the characteristic loads caused by pitting corrosion were smaller than the pitting weight loss ratio due to the stress concentration.

本文首先对Q690高强钢板进行了盐雾试验。腐蚀试验后，去除腐蚀产物，得到失重率。然后通过 3D 表面轮廓仪扫描粗糙表面的形貌，并导出腐蚀表面的 3D 坐标。根据数据确定地形特征参数，计算均匀腐蚀深度，对点腐蚀深度进行极值分析，研究其随机特征。最后，对腐蚀面进行修复，建立扫描段的有限元模型，并通过实验结果进行验证，并用于应力集中分析。实验结果表明，地形特征参数与失重率呈线性相关，最大点蚀深度符合Frechat分布。通过有限元分析得出，在单轴拉伸载荷作用下，锈蚀钢板表现出明显的应力集中效应，大部分节点处于多轴应力状态。在特征载荷方面，均匀腐蚀和点蚀都会引起屈服载荷和极限载荷退化。对于均匀腐蚀成分，特征载荷的损失百分比等于相应的失重比。然而，点腐蚀引起的特征载荷的损失百分比小于由于应力集中引起的点蚀重量损失率。