Influence of a corrosion pit on behavior of a nearby crack.

Corrosion is a very complex problem, which is affected by many factors. Corrosion generally produces serious changes in the surface morphology and corrosion pits that develop on the structure surface can interact with other defect such as cracks. In this paper, the influence of a corrosion pit on fatigue propagation of a perpendicular crack in a bar subjected to tensile loading is analyzed. Particularly, the effect of various corrosion pit sizes and distances from the crack on basic fracture parameters is investigated. A numerical model of the described specimen with a crack and a corrosion pit close to each other has been created and finite element calculations have been performed in order to obtain dependences of stress intensity factor ranges and T-stress on the crack length. The plots obtained enable to formulate conclusions on crack behavior near a corrosion pit. It was found out that some configurations could lead to slower fatigue crack propagation and could slightly weaken the dominant mode I of loading. [ABSTRACT FROM AUTHOR]