Numerical modeling of hydrogen diffusion in structural steels under cathodic overprotection and its effects on fatigue crack propagation

作者：Palma Carrasco J; Silva Diniz D; Andrade Barbosa J M; Almeida Silva A

来源：Materialwissenschaft und Werkstofftechnik, 2012, 43(5): 392-398.

DOI：10.1002/mawe.201200971

• Continuum Damage Mechanics
• Hydrogen Embrittlement
• Cathodic Overprotection
• Fatigue Cracks Propagation
• Kontinuumsschadigungsmechanik
• Wasserstoffversprodung
• kathodischer Uberschutz
• Ermudungsrissausbreitung

This paper presents a numerical simulation of the effect of hydrogen atomic diffusion on fatigue crack propagation on structural steels. The simulation was performed with a specimen type CT of API 5CT P110 steel, loaded in the tensile opening mode, in plane strain state and under the effects of a cyclic mechanical load and the hydrogen concentration at the crack tip. As hydrogen source, a cathodic protection system was considered, commonly used in subsea pipelines. The equations of evolution of variables at the crack tip form a non-linear system of ordinary differential equations that was solved by means of the 4th order Runge-Kutta method. The solid-solid diffusion through the lattice ahead of the crack tip was simulated using the finite difference method. The simulations results show that under these conditions, the fatigue crack evolution process is enhanced by the hydrogen presence in the material, and that the start time of the crack propagation decreases as its concentration increases. These results show good correlation and consistency with macroscopic observations, providing a better understanding of hydrogen embrittlement in fatigue crack propagation processes in structural steels.

• 出版日期2012-5