Structural damage identification technology for fluid pipes is highly practical in engineering field. For the purpose of realizing the pipeline damage localization, the feasibility and recognition accuracy of the ultrasonic guided wave testing technique in fluid pipes are discussed in this study. A pipe made of 20# carbon steel is used to investigate the damage localization. According to dispersion equations, numerical method is applied to obtain various modal dispersion curves. Based on pipe wave propagation theory, and considering the influences of pipe wave patterns, dispersion characteristics and propagation velocity and the requirement of avoiding the truncated frequency, the excitation signals are selected. The guided wave transmission mechanism in the fluid pipes with different fluids is analyzed numerically by means of ABAQUS software. The method of probability density function is applied to realize fluid pipe damage localization. Finally, notches and holes are introduced to the fluid pipe in the experiment to verify the effectiveness of the proposed method. The experimental results and simulation results are consistent. The engineering practical value of this method is proved.%研究工程中流体管道的结构损伤识别技术具有现实的意义.以实现管道损伤定位为目的,探讨超声导波检测技术在流体管道的结构损伤识别中的可行性以及其识别精度.选择材料为20#碳钢的圆管为研究对象,根据频散方程利用数值法求解其各个模态频散曲线.以管中导波的传播原理为基础,从管中导波的模式、频散特征、避开截止频率、传播速度等方面因素选择激励信号,通过Abaqus有限元仿真分析导波在流体管道中的传播机理,利用概率密度函数法实现流体管道损伤定位.最后通过在管道上引入切槽损伤和孔损伤进行实验,对定位方法进行验证,实验结果与仿真分析基本吻合,证明了该方法的工程实用价值.
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