基于半解析有限元法的多层管超声导波数值模拟与试验研究

Numerical Simulation and Experimental Investigation on Ultrasonic Guided Waves in Multilayered Pipes Based on SAFE

超声导波检测技术因其检测距离远、检测效率高,在工业管道的无损检测和健康监测中显示出良好的应用前景,但是目前对于广泛应用于工业领域的多层管的导波检测研究仍较少。应用半解析有限元法(Semi-analytical finite element method,SAFE),基于虚功原理构建超声导波在多层管中传播的控制方程,求解导波在多层管中传播的特性,导出多层管中导波的频散特性,包括相速度、能量速度、衰减、波结构等,为导波检测多层管时选择模态和频率提供理论依据。讨论多层管中黏弹性介质引入的阻尼对导波传播的影响,求解多层管中的导波衰减频散曲线,用于指导多层管检测,并通过数值仿真以及利用MSGW磁致伸缩导波检测仪检测单层钢管和衬塑钢管试验验证部分理论结果。

Ultrasonic guided waves detecting technology has shown a good prospect in non-destructive testing and health monitoring of industrial pipelines, thanks to its advantages such as long detection range and high detection efficiency, but very few researches have been conducted on guided waves inspection of multilayered pipes, which is widely used in industrial circle. The semi-analytical finite element method is used to formulate the governing equation for guided waves propagating in multilayered pipes on the basis of the virtual work principle, dispersive characteristics including phase velocity, energy velocity, attenuation and wave structures are extracted by solving governing equation, which provide the basis for selecting mode and frequency during application. The effect of viscoelastic material on guided waves propagating in multilayered pipes is taken into consideration, and the dispersive solutions for multilayered pipes are obtained in terms of attenuation curves, which can be used to supervise the inspection of multilayered pipes, furthermore, the theoretical result is partly verified by numerical simulation as well as detecting single-layered pipe and lining plastic pipe by using MSGW guided waves detecting instrument.