摘要
在管道残余厚度检测过程中,存在噪声和遇小缺陷信号发生畸变的问题,导致检测结果不准确.基于变分模态分解(variational mode decomposition,VMD)法的电磁超声信号降噪为了避免过分解或欠分解,需对其关键参数分解模态数K和惩罚因子α进行寻优.本文首次将三角拓扑聚合优化(triangulation topology aggregation optimizer,TTAO)方法与变分模态分解法结合,通过TTAO算法对VMD算法中的最佳参数组合进行寻优,实现了两参数同步优化,再将最佳参数组合代入VMD算法进行分解,计算相关系数来选取合适的本征模态函数(intrinsic mode function,IMF)进行重构,得到处理后的信号.当管道内壁存在小缺陷时,会产生缺陷和底部两种回波.针对常规脉冲回波反射法对内壁出现尺寸小于换能线圈面积缺陷时回波信号发生畸变引起的残余厚度测量误差大的问题,提出了基于4次回波的管道残余厚度检测法,该方法通过对比一次、三次回波波包峰值时间间隔和二次、四次回波波包峰值时间间隔判断小缺陷的存在,进而区分缺陷回波与底部回波,并利用两段时间间隔差值计算出管道内壁缺陷深度,进而得出管道残余厚度值.通过实验对比脉冲反射法和基于TTAO-VMD和4次回波的管道残余厚度检测方法,结果表明无论是否存在小缺陷,本文提出的方法均可精确测量残余厚度,平均相对误差为0.28%.
When detecting the residual thickness of a pipeline,the presence of noise and distortion of small defect signals can lead to detection errors.To avoid over-decomposition or under-decomposition in the variational mode de-composition(VMD)of electromagnetic ultrasonic signals,it is necessary to optimize the key parameters:the number of decomposition modes K and the penalty factorα.This paper combines the triangulation topology aggregation optimizer(TTAO)with the VMD algorithm for the first time.TTAO is used to optimize the best parameter combination for the VMD algorithm,achieving the synchronous optimization of the two parameters;the best parameter combination is then fed into the VMD algorithm for decomposition.The correlation coefficients are calculated to select the appro-priate number of intrinsic mode functions(IMFs)for reconstruction,yielding the processed signal.When there are small defects on the inner wall of the pipeline,two types of echoes,defect echoes and bottom echoes,are generated.Aimed at the problem of large measurement errors for residual wall thickness due to signal distortion when using the conventional pulse echo reflection method for the defects whose sizes are smaller than the transducer coil area,a pipeline residual wall thickness detection method based on quad echoes is proposed.This method judges the existence of small defects by comparing the time intervals between the peaks of the primary and tertiary echo wave packets and those of the secondary and quaternary echo wave packets,thereby distinguishing between defect echoes and bottom echoes.The depth of the inner wall defect of the pipeline is calculated using the difference between the two time intervals,and thus the residual wall thickness of the pipeline is obtained.Experiments were conducted to compare the pulse reflection method with the proposed pipeline residual thickness detection based on TTAO-VMD and quad echoes.The results show that the proposed method can accurately measure residual wall thickness,whether there are small defects or not,with an average relative error of 0.28%.
作者
王超
邢一皇
郭琪
王璇
Wang Chao;Xing Yihuang;Guo Qi;Wang Xuan(School of Electrical and Information Engineering,Tianjin University,Tianjin 300072,China;Key Laboratory of Digital Twin Generic Technology in Special Equipment for State Market Regulation,Tianjin Special Equipment Inspection Institute,Tianjin 300192,China)
出处
《天津大学学报(自然科学与工程技术版)》
北大核心
2025年第7期674-682,共9页
Journal of Tianjin University:Science and Technology
基金
天津市重点研发计划资助项目(23YFZCSN00080).
关键词
无损检测
电磁超声
变分模态分解
残余厚度
non-destructive testing
electromagnetic acoustic
variational mode decomposition(VMD)
residual thickness
