基于 L（0,2）超声导波的管道裂纹损伤回波特征分析

摘要

Based on L(0,2)ultrasonic guided wave,this paper analyzes echo characteristic of pipeline crack damage.First-ly,on the basis of ANSYS software and by means of canceling some cells,finite element model for crack defect of the metal pipeline was established,in addition,pulse-echo method was used for simulating L(0,2)module wave to inspire the pipe-line.Secondly,time travel curve of pipeline crack was analyzed for extracting characteristic parameters such as defect echo-ing time,reflection coefficient and so on.By comparing and simulating axial location and practical position of crack,effec-tiveness of this crack model was verified.By analyzing relationships between axial length,circumferential angle,radial depth and sectional area of the crack and reflection coefficient,it was concluded that axial location of the crack could be de-termined by echo arrival time and wave speed ,by using time domain analysis method,location error was less than 5%.In addition,when radial depth and circumferential angle increased,reflection coefficient largened.When radial depth and cir-cumferential angle increased at the same rate,affect of radial depth on crack reflection was greater.When sectional area in-creased,reflection coefficient increased as well.%基于 L(0,2)模态超声导波分析管道裂纹损伤的回波特征。首先,基于 ANSYS 软件,通过删除单元的方法建立金属管道的裂纹缺陷的有限元模型；用脉冲–回波的方法模拟 L(0,2)模态波对管道进行激励。其次,对得到的管道裂纹时程曲线进行分析,提取缺陷回波时间、反射系数等特征参数,通过对比模拟的裂纹轴向定位与实际裂纹位置,验证了管道裂纹模型的有效性；对裂纹轴向长度、周向角度、径向深度和裂纹截面积与反射系数的关系进行分析,得出结论：裂纹的轴向定位可以由裂纹回波到达的时间和波速确定,利用时域分析方法,定位误差不超过5%；裂缝径向深度和周向角度增加时,反射系数变大；当径向深度与周向角度同比例增加时,径向深度对裂纹反射的影响更大；裂纹截面积增大时,反射系数增大。