桥梁缆索钢丝裂纹扩展速率预测及疲劳寿命计算  

Crack Growth Rate Prediction and Fatigue Life Calculation of Bridge Cable Steel Wires

作　　者：王天鹏 张建仁[1] 王磊 马亚飞 WANG Tianpeng;ZHANG Jianren;WANG Lei;MA Yafei(School of Civil Engineering,Changsha University of Science&Technology,Changsha 410114,China;School of Civil Engineering,Central South University of Forestry and Technology,Changsha 410004,China)

机构地区：[1]长沙理工大学土木工程学院,湖南长沙410114 [2]中南林业科技大学土木工程学院,湖南长沙410004

出　　处：《湖南大学学报（自然科学版）》2021年第3期24-33,共10页Journal of Hunan University:Natural Sciences

基　　金：国家重点基础研究发展规划(973计划)项目(2015CB057705);国家自然科学基金资助项目(51478050);湖南省自然科学基金资助项目(2019JJ40313)。

摘　　要：为给桥梁缆索钢丝疲劳性能分析提供简单有效的方法,根据钢丝的微观组织结构和相关试验数据的统计分析结果,建立了钢丝疲劳裂纹扩展速率预测模型,并给出了模型参数的计算方法.通过变载刻痕法在原状钢丝上获取了稳定扩展区的疲劳裂纹扩展速率,预测模型较好地描述了试验获取的数据和文献中近门槛值区域钢丝的疲劳裂纹扩展规律.在此基础上,通过断裂力学方法计算了新钢丝和腐蚀钢丝的疲劳寿命并与试验数据相比较,结果表明:钢丝腐蚀不会对疲劳裂纹扩展速率产生影响,仍可用未腐蚀钢丝的力学性能通过本文方法进行预测,腐蚀钢丝疲劳寿命的变化是由于初始裂纹尺寸发生改变而引起.对于新钢丝和轻微腐蚀钢丝,可采用等效初始裂纹法进行疲劳寿命计算;当钢丝腐蚀较为严重时,疲劳总寿命基本由裂纹扩展寿命构成,初始裂纹尺寸即为真实锈坑深度.鉴于蚀坑深度分布的随机性,宜采用最大蚀坑深度对腐蚀钢丝进行疲劳寿命计算.In order to provide a simple and effective method for the fatigue performance analysis of bridge cable steel wires,according to the microstructure of the steel wire and statistical analysis results of relevant test data,a prediction model of steel wire fatigue crack growth rate is established,and the calculation method of model parameters is given.The fatigue crack growth rate in the stable growth region is obtained on the original steel wire by the variable load indentation method.The prediction model can better describe the data obtained from the test and the fatigue crack growth law of the steel wire in the near threshold region in the literature.On this basis,the fatigue life of new steel wire and corroded steel wire is calculated by the fracture mechanics method and compared with the test data.The results show that the corrosion will not affect the fatigue crack growth rate of the steel wire.The mechanical properties of the uncorroded steel wire can still be predicted by this method.The change of fatigue life of the corroded steel wire is attributed to the change of the initial flaw size.For new steel wire and slightly corroded steel wire,the equivalent initial flaw size method can be used to calculate the fatigue life;when the steel wire is corroded seriously,the total fatigue life is basically composed of the crack propagation life,and the initial flaw size is the true depth of rust pit.In view of the randomness of pit depth distribution,the maximum pit depth should be used to calculate the fatigue life of corroded steel wire.

关 键 词：桥梁缆索钢丝 裂纹扩展 初始裂纹 疲劳寿命 断裂力学 

分 类 号：U443.38[建筑科学—桥梁与隧道工程]