Effect of residual stress-strain profiles on hydrogen-induced fracture of prestressing steel wires.

We analyze the influence of the distributions of residual stresses and strains formed after the surface treatment of cold-drawn steel wires used as the reinforcement of prestressed reinforced concrete on the susceptibility of these wires to hydrogen embrittlement characterized by the time to fracture in the tests carried out according to the regulations of the FIP (Fédération Internationale de la Précontrainte). A computational model is proposed for the prediction of the durability of wires in corrosive hydrogenated media. In the model, the accumulation of hydrogen in potential sites of fracture as a result of diffusion under the influence of stresses and plastic strains is analyzed and a criterion of critical concentration of hydrogen specifying the time of local fracture depending on the stress-strain state is formulated. The enables us to predict the influence of specific features of the distributions of residual stresses and plastic strains after various types of thermal treatment on the durability of wires under the conditions of hydrogen embrittlement. [ABSTRACT FROM AUTHOR]