Fatigue life assessment of high-strength steel wires: Beach marks test and numerical investigation

High-strength steel wires are widely used in large-span bridges. Fatigue damage of steel wires is becoming more and more prominent under adverse environment and repeated load. This paper performed the fatigue crack growth rate tests of high strength steel wires under different stress ratios. The striated fracture morphology was obtained by stepwise fatigue loading method. The fatigue crack growth rate of steel wire was determined by measuring fracture stripe width by optical microscope. The experimental curves of fatigue crack growth rate versus stress intensity factor range under various stress ratios were obtained. The fracture morphology of steel wires after fatigue was observed by scanning electron microscopy. The characterization parameters of fatigue crack growth and critical fracture required for numerical simulation were obtained based on experimental results and statistical method. Following that, a numerical fatigue crack propagation model was established combined with ABAQUS and FRANC3D. The numerical model was validated by experimental observations in the present study and open literature. A parametric analysis method considering initial pit depth and stress amplitude was proposed to evaluate the residual life of steel wires. The results showed that the linear elastic fracture mechanics and numerical simulation-based method can be used to assess the fatigue life of virgin and corroded steel wires.