Plateau frequency exploration of longitudinal guided waves for stress monitoring of steel strand  

钢绞线应力监测的纵向超声导波平台频率获取

作　　者：ZHANG Jing LI Xuejian LI Gang YUAN Ye YANG Dong 张静;李雪健;李刚;袁冶;杨栋(合肥工业大学土木工程学院,合肥230009;香港大学土木工程学院,香港999077;广州大学工程抗震研究中心,广州510006)

机构地区：[1]Department of Civil Engineering,Hefei University of Technology,Hefei 230009,China [2]Department of Civil Engineering,The University of Hong Kong,Hong Kong 999077,China [3]Earthquake Engineering Research&Test Center,Guangzhou University,Guangzhou 510006,China

出　　处：《Journal of Southeast University(English Edition)》2025年第1期44-50,共7页东南大学学报(英文版)

基　　金：The National Natural Science Foundation of China(No.52278303).

摘　　要：To tackle the issue of notch frequency and center frequency drift of the L(0,1)mode guided wave in ultra⁃sonic guided wave⁃based stress monitoring of prestressed steel strands,a method using higher⁃order mode plateau fre⁃quencies is adopted.First,the correlation between group velocity peaks and phase velocities at these plateau frequen⁃cies is analyzed.This analysis establishes a quantitative rela⁃tionship between phase velocity and stress in the steel strand,providing a theoretical foundation for stress monitor⁃ing.Then the two⁃dimensional Fourier transform is em⁃ployed to separate wave modes.Dynamic programming techniques are applied in the frequency⁃velocity domain to extract higher⁃order modes.By identifying the group veloc⁃ity peaks of these separated higher⁃order modes,the plateau frequencies of guided waves are determined,enabling indi⁃rect measurement of stress in the steel strand.To validate this method,finite element simulations are conducted under three scenarios.Results show that the higher⁃order modes of transient signals from three different positions can be ac⁃curately extracted,leading to successful cable stress moni⁃toring.This approach effectively circumvents the issue of guided wave frequency drift and improves stress monitoring accuracy.Consequently,it significantly improves the appli⁃cation of ultrasonic guided wave technology in structural health monitoring.通过研究超声导波在预应力钢绞线应力监测中遇到的L(0,1)模态导波缺口频率及陷频中心漂移的问题,提出一种基于高阶模态平台频率的应力监测方法。首先分析群速度峰值与平台频率处相速度的关联特性,建立了相速度与钢绞线应力之间的定量关系,为应力监测提供理论依据;接着采用二维傅里叶变换对导波模态进行分离,在频率-波速域应用动态规划技术提取高阶模态,通过分离后的高阶模态群速度峰值确定导波平台频率,实现钢绞线应力间接测量;最后,基于有限元模型验证了3种不同工况下所提平台频率选取方法的有效性。结果表明,利用3个不同位置的瞬态信号均能从中准确提取高阶模态并实现应力监测,且可有效避免导波频率漂移的影响,提高监测准确性,有助于增强超声导波技术在结构健康监测中的应用效果。

关 键 词：steel strand ultrasonic guided wave plateau frequency mode separation stress monitoring 

分 类 号：U448[建筑科学—桥梁与隧道工程]