超声导波检测技术作为一种新兴的无损检测技术广泛应用于圆管类结构.为选择合适于不同缺陷检测的导波模态,推导分析了圆管导波传播的运动方程和频散方程;利用数值计算的方法得到了超声导波在圆管中传播的频散曲线和各模态沿壁厚方向的位移分布图,分析得出各个模态对不同缺陷的敏感程度;以一种特定的圆管为例,建立圆管缺陷有限元模型,对不同类型圆管缺陷对导波传播特性的影响进行仿真计算.结果表明,纵向模态对周向缺陷比较敏感,而扭转模态则对轴向缺陷更敏感,仿真结果与理论分析结果相吻合,为圆管缺陷检测的超声导波模态选择提供了理论依据.%Ultrasonic guided wave detection technology as a new non-destructive testing technology is widely used in circular tube structure. In order to select the suitable wave mode for detecting different defects, the equations of motion and dispersion of the guided wave propagating in the barrel are deduced on the basis of elastic mechanics. The dispersion curve of the ultrasonic guided wave propagating in the barrel and the displacement distribution of each mode along the direction of the wall thickness are obtained with the numerical calculation method,on the basis of which the sensitivity of each mode to different defects is analyzed. Take a specific tube as an example,finite element model of tube defects is established,and the impact of different types of tube defects on the characteristics of guided wave propagation is analyzed through simulated calculation. The results show that the longitudinal mode is sensitive to the circumferential defect,and the torsional mode is more sensitive to the axial defect. The simulation results are in agreement with those of theoretical analysis, providing the theoretical basis for the mode selection of ultrasonic guided wave to detect theround tube defects.
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