基于振动频率的斜拉索损伤程度识别  

Damage degree identification of stay cables based on vibration frequency

作　　者：程远 张素侠[1] 刘洪德 CHENG Yuan;ZHANG Suxia;LIU Hongde(School of Mechanical Engineering,Tianjin University,Tianjin 300354,China)

机构地区：[1]天津大学机械工程学院,天津300354

出　　处：《武汉大学学报(工学版)》2025年第1期134-141,共8页Engineering Journal of Wuhan University

基　　金：装备预研基金重点项目(编号:61403110101);天津市交通运输科技发展计划资助项目(编号:2019-15)。

摘　　要：针对斜拉桥拉索在投入使用期间产生的损伤展开了斜拉索损伤识别研究。根据由拉索频率方程推导出的拉索抗弯刚度和拉索索力表达式,分别应用拉索抗弯刚度变化率(change rate of bending stiffness,CRBS)和拉索索力变化率(change rate of cable force,CRCF)这2个损伤指标进行拉索抗弯刚度和索力的损伤程度判断。在此基础上,通过选取拉索4、6、8阶振动频率进行计算,并对CRBS和CRCF进行求和平均后提出了平均抗弯刚度变化率μ_(CRBS)以及平均拉索索力变化率μ_(CRCF)这2个平均指标。参考应用Ernst公式,对拉索考虑抗弯刚度以及索力折减等因素的换算抗弯刚度进行了保守的转换估计,分别提出并计算了拉索换算抗弯刚度的理论值变化率CRBS′和平均计算值变化率CRBS",结果证明CRBS"对拉索实际换算抗弯刚度的损伤程度具有较好的识别效果。最后,通过拉索切割模拟实验验证了抗弯刚度与索力的折减对频率的影响是有效的。In view of the damage caused by the cable of the cable-stayed bridge during its operation,this paper conducts the research on the damage identification of stay cables.According to the flexure stiffness of the cable and the expression of the cable force derived from the cable frequency equation,the change rate of bending stiffness(CRBS)and the change rate of cable force(CRCF)are used to judge the degree of damage to bending stiffness of the cable and cable force.On this basis,by selecting the 4th,6th,and 8th order vibration frequencies of the cable,two average indexes,the average flexure stiffness change rate(μ_(CRBS))and the average cable force change rate(μ_(CRCF)),are proposed after summing and averaging CRBS and CRCF.Later,with reference to the Ernst formula,a conservative conversion and estimate of the converted flexure stiffness of the cable considering factors such as flexure rigidity and cable force reduction is carried out,and the theoretical value change rate of the converted flexural stiffness of the cable(CRBS′)and the average calculated value change rate(CRBS")are proposed and calculated.The results prove that CRBS"has a better recognition effect on the damage degree of the actual converted bending stiffness of the cable.Finally,the effect of bending stiffness and cable force reduction on frequency is verified by cable cutting simulation experiment.

关 键 词：斜拉索 损伤识别 振动频率 抗弯刚度 索力 

分 类 号：U443.38[建筑科学—桥梁与隧道工程]