Boundary Element Method (BEM) Analysis for Galvanic Corrosion of Hot Dip Galvanized Steel Immersed in Seawater

A numerical analysis of galvanic corrosion of hot-dip galvanized steel immersed in seawater was presented. The analysis was based on the boundary element methods (BEMs) coupled with Newton-Raphson iterative technique to treat the nonlinear boundary conditions, which were determined by the experimental polarization curves. Results showed that galvanic current density concentrates on the boundary of steel substrate and zinc coating, and the sacrificial protection of zinc coating to steel substrate results in overprotection of steel cathode. Not only oxygen reduction but also hydrogen reduction could occur as cathode reactions, which probably led up to the adsorption and absorption of hydrogen atoms. Flat galvanized steel tensile sample shows a brittle behavior similar to hydrogen embrittlement according to the SSRT (show strain rate test) in seawater.

缺陷识别反问题的研究状况与若干进展

回顾了缺陷识别反问题的发展状况，评述了几类典型识别方法：基于势函理论的电学法，静态BEM优化迭代法，射线法，T矩阵法，Born近似法，边界积分方程及边界元法。介绍了作者建立的裂纹及夹杂识别的迭代优化法。指出了缺陷识别反问题需要研究的主要问题。