Abstract: The mechanical properties of wires of cable-stayed bridges are extremely sensitive to corrosion. Corrosion pits on the surface of steel wires are caused by corrosion, which will lead to stress concentration and weaken local fatigue resistance of steel wires, and attract fatigue cracks to nucleate from here. This is usually the direct reason for the reduction of cable bearing capacity and service life of cable-stayed bridges. The influence of the length, width and depth of the pit on the stress concentration is discussed by means of numerical simulation. Firstly, a finite element model of a high-strength steel wire is established using finite element software ANSYS. Based on the different scale of pits, i.e. depth-width ratio and length-width ratio, the deep narrow and open pits are simulated. According to the data obtained by finite element calculation, the curve of the factors of pit size and stress concentration coefficient is fitted. According to the curve, the approximate calculation formula of stress concentration coefficient of semi-ellipsoid with different size ratio is established. Based on the stress distribution diagram of pits and the variation law of stress concentration coefficient with size ratio, the influences of length, width and depth of pits on stress concentration effect and stress distribution at pits are discussed, and the influences of three size factors on stress concentration effect are compared horizontally. The results show that the stress concentration coefficient of high-strength steel wire increases with the increase of the depth-width ratio or width-depth ratio of the corrosion pit, and decreases with its length. In addition, the variation of pit length has the most significant influence on the stress concentration coefficient of high-strength steel wire, followed by the pit depth and the pit width has the least influence.

Key words: corroded wires, stress concentration coefficient, corrosion pit, parametric analysis, finite element analysis