Experimental study and residual fatigue life assessment of corroded high-tensile steel wires using 3D scanning technology

Abstract

Fatigue damage of bridge suspender is a serious problem under long-term environmental erosion and repeated vehicle loads. This paper quantifies the effects of corrosion on the residual fatigue life of steel wires in bridge suspender. A predictive model was proposed to estimate the fatigue life of corroded steel wires based on the equivalent initial flaw size method, in which both corrosion growth stage and fatigue crack propagation stage were considered. The pitting corrosion-induced stress concentration was incorporated into the stress intensity factor model. The theoretical residual fatigue life can be obtained by integrating the fatigue crack growth model from the equivalent initial crack size to a critical crack length. The effects of corrosion on the fatigue performance of steel wires with various corrosion degrees were investigated by fatigue loading tests. The fracture morphology of the steel wires after fatigue was observed using scanning electron microscopy. The relationships between corrosion degrees and fatigue lives of the steel wires were provided. The surface morphology of corroded steel wire was scanned by 3D scanning technology, and a three-dimension model was established. A finite element model of corroded steel wires was established after the scanning model was processed by the Geomagic software. Following that, the relationship between stress concentration factor and corrosion degree was analyzed. A fatigue life prediction method based on the equivalent initial crack size was verified by the experimental observation of various corroded steel wires and the data in open literature.