为研究坑蚀对高强钢丝疲劳曲线方程的影响,对 5 根无锈蚀高强钢丝和 25 根不同坑蚀尺寸的钢丝进行通电加速锈蚀,进行单轴拉伸疲劳试验,结合斜拉索坑蚀高强钢丝的轴拉疲劳试验,分析坑蚀对钢丝疲劳寿命的影响,建立考虑坑蚀系数和应力幅的统一疲劳曲线方程.研究结果表明,由于截面积减小和应力集中,高强钢丝的疲劳断裂均发生在坑蚀部位.坑蚀对钢丝疲劳寿命的影响主要表现为S-N曲线下移和衰减速率变化,与疲劳曲线参数C,m没有良好的相关性.基于应力幅和坑蚀的影响规律,建立指数函数修正的坑蚀高强钢丝统一S-Nc 曲线方程.验算结果证明该模型在相对较低的疲劳寿命阶段具有较好的适应性,误差基本控制在±30%内.
In order to study the fatigue curve equation of high-strength steel wires with corrosion excavation,the 5 non-corroded steel wires and 25 steel wires with different excavation sizes is energized to accelerate corrosion,uniaxial tensile fatingue test was carried out,and a unified fatigue curve equation considering excavationing coefficient and stress amplitude wire was established,combined with the axial tensile fatigue test of high-strength steel wire pitted by cable-stayed cable,the influence of excavationing on fatigue life of steel wire is analyzed,a unified fatigue curve equation considering excavationing coefficient and stress amplitude is established.Results showed that the fatigue fracture of high strength steel wire mostly occurred at the excavationing position,due to the decrease of cross-sectional area and the stress concentration.The effect of corrosion excavation on fatigue life was shown as the downward shift and decay rate of S-N curve,and there was little correlation with parameters C and m of S-N curve.Therefore,a unified S-Nc curve equation of excavationed high-strength steel wire with modified exponential function is established,based on the influence law of stress amplitude and excavationing.The calculation results showed that the model has good adaptability in the relatively low fatigue life period,and the error was basically within±30%.