交变荷载和氯盐环境作用下钢绞线的腐蚀疲劳性能研究

Experimental on the Corrosion Fatigue Behavior of Steel Strands Under theCouple Effect of Variable Load and Choride Environment

为探寻交变荷载和氯盐环境对拉索中各钢绞线力学性能的影响,进而预测不同腐蚀区绞线的疲劳寿命,本研究通过盐雾腐蚀试验来模拟钢绞线在交变荷载和氯盐环境共同作用下的腐蚀情况,考虑不同应力幅对钢绞线腐蚀疲劳寿命的影响,并运用灰度处理方法,对钢绞线腐蚀程度进行量化分区,便于分析不同腐蚀区钢绞线的破坏模式。研究结果表明:拉索外侧钢绞线比拉索内侧钢绞线更容易腐蚀,其腐蚀程度与所施加应力幅相关,应力幅越大,钢绞线腐蚀程度越高,开裂韧性值越低,易发生脆性破坏。随着应力幅值降低,钢绞线开裂韧性值提高,钢绞线破坏模式由脆性破坏转变为延性破坏。此外,通过疲劳试验,基于三参数法,提出不同腐蚀程度的钢绞线的疲劳寿命预测模型,为进一步探究拉索疲劳腐蚀机理提供参考。

In order to explore the effects caused by variable load and chloride environment on the mechanical properties of each steel strand in cables even to predict their corrosion fatigue life.In this paper,a salt spray corrosion test is set up to simulate the corrosion process of steel strands under the couple effect of chloride environment and variable load with different stress amplitude.and the corrosion laws of steel strands are obtained by proposing grayscale analysis on the cables.The corrosion degrees of the steel strands are divided according to the gray treatment solution.The results show that The steel strand outside of the cable is more likely to corrode than the steel strand inside of the cable,and the corrosion degree is related to the stress amplitude.with the stress amplitude applied on the steel strand increased,the corrosion degree of wires seemed to be se-riously,the cracking toughness is lower than before,and the brittleness failure is easy to occur.With the decrease of stress amplitude,the crac-king toughness of steel strand increases,and the failure mode of steel strand will be changed from brittle failure mode to ductile failure mode.Additionally,the steel strands corrosion fatigue predicted model of different corrosion grades are obtained by the three-parameter method,which contributes to the prediction and evaluation of the fatigue life of corrosion cables.