基于T(0,1)扭转波的管道纵向裂纹定位方法  

Locating method of longitudinal crack in pipes using ultrasonic guided wave T(0,1)

作　　者：王伟 游鹏辉[2] 钟力强 徐俊[2] 钟万里 曹韬宇 

机构地区：[1]广东电网有限公司电力科学研究院,广东广州510080 [2]武汉大学动力与机械学院,湖北武汉430072

出　　处：《中国测试》2016年第6期139-144,共6页China Measurement & Test

摘　　要：针对平行于管道轴线的纵向裂纹缺陷检测,分析导波激励信号的中心频率、缺陷轴向长度等因素对反射系数的综合影响。首先,建立带裂纹缺陷管道的有限元模型;根据频散曲线特征,确定形成T(0,1)扭转模态波的激励频率;其次,在低频段取3种不同的激励信号中心频率,对纵向裂纹缺陷模拟检测的数值仿真,通过改变裂纹的轴向长度,分析其对缺陷回波特征的影响。结果表明:T(0,1)扭转波检测纵向裂纹的轴向定位误差约为5%;周向反射系数最大值出现在裂纹对应的周向位置;设置中心频率为27 k Hz时,回波反射系数随裂纹长度的增大,先增大后减小。通过以上分析可以得出T(0,1)扭转波对纵向裂纹轴向定位和周向定位的方法。How the factors such as the center frequency of guided wave excitation signals and the longitudinal lengths of defects influence the reflection coefficient have been discussed and studied to examine the longitudinal crack defects in parallel to the pipe axis. First, a finite element model for pipeline with crack defects was built and the excitation frequency of T（0,1） torsion mode was determined according to the characteristics of frequency dispersion curve. Second,three kinds of center frequency excitation signals were taken at the low-frequency stage. The numerical simulation of longitudinal crack defects was conducted. The impact on flaw echo characteristics generated after changing the axial length of the crack was analyzed. The results show that the axial positioning error of T（0,1） torsion wave is about 5%;the maximum circumferential reflection coefficient appears in the circumferential position corresponding to the crack; and when the center frequency is set at 27 k Hz,the echo reflection coefficient first increases and then decreases with the crack length growth. The way to determine the axial and circumferential locations of longitudinal cracks with via the T（0,1） torsion wave is thus obtained through the analysis above.

关 键 词：导波 频散 反射系数 定位 

分 类 号：TU473.16[建筑科学—结构工程]