厚壁管道缺陷周向SH导波检测的有限元模拟研究

Finite Element Simulation Study on Detection of Thick-walled Pipes' Defect with Circumferential SH Guided Waves

本研究采用有限元仿真软件建立了厚壁管道周向SH0模态导波检测模型,分析研究了周向SH0模态导波的波结构特征及其群速度,并利用该模态导波对不同壁厚位置缺陷进行了检测。结果表明:仿真计算与理论分析的波结构曲线基本吻合,同时声波传播速度与理论频散曲线中周向SH0模态导波在60 k Hz处的群速度相差很小,从而验证了该有限元模型的有效性;在针对不同壁厚位置缺陷的模拟检测中,周向SH0模态导波对外壁缺陷的检测灵敏度较高,中部缺陷稍低,内壁缺陷则难以检测到。

In this paper,based on finite element simulation software the thick-walled pipes＇ detection model by using circumferential SH0 mode guided waves was established; the wave structure and the group velocity of the mode guided waves were analyzed; the detection of different wall thickness defects was carried using the mode guided waves. The results show that the wave structure curve of simulation was consistent with theoretical analysis,while the difference of ultrasonic wave propagation velocity and the group velocity of circumferential SH0 mode guided waves at 60 k Hz in theoretical dispersion curve was small. These have verified effectiveness of the finite element model. The simulated detection results of the different wall thickness defects show that the detection sensitivity in external wall defect was highest and lower in the middle thick wall defect,while the defect located in the internal wall was difficult to detect.