超声界面波在充液双金属复合管道中的传播特性分析

随着管道运输行业的发展,复合管道越来越多地应用于机械、能源、化工等领域.利用超声界面波对复合管道的界面位置进行损伤探测成为机械装备超声无损检测研究的新方向.以充液金属复合管道为研究对象,采用多物理场有限元分析软件建立了充液复合管道的有限元模型,利用电信号激励超声界面波,分析了超声界面波在管道中的传播特性,并分析了不同液体对超声界面波的影响.结果表明:与空的复合管道相比,超声界面波在充液复合管道中的传播特性差别明显.在充液双金属复合管道中,超声界面波一部分来自初始激励,另一部分来自液体中激励的超声导波;随着传播的进行,初始激励的超声界面波迁移至固液界面处,形成固-液界面波,并逐渐泄漏至液体中;液体中的超声导波每经过一次管道壁面反射,在固液界面处形成一股新的固-液界面波,从而形成等间隔传播的固-液界面波群组.液体密度影响界面波的能量分布:液体密度越大,界面波能量越分散;液体的纵波波速影响固-液界面波的形成速度:纵波波速越快,固-液界面波形成越快.研究工作和分析结果可为管道损伤检测提供理论依据.

Analysis of ultrasonic interface wave propagation in liquid filled bimetal composite pipe

With the development of pipeline transportation industry, composite pipeline is more and more used in machinery, energy, chemical and other fields. It is a new research direction of ultrasonic nondestructive testing of mechanical equipment to detect the damage of composite pipeline by ultrasonic interface wave. In this paper, the liquid filled metal composite pipeline is taken as the research object, the finite element model of the liquid filled composite pipeline is established by using the multi physical field finite element analysis software, the ultrasonic interface wave is excited by the electrical signal, the propagation characteristics of the ultrasonic interface wave in the pipeline are analyzed, and the influence of different liquids on the ultrasonic interface wave is analyzed. The results show that: in the liquid filled bimetal composite pipeline, the ultrasonic interface wave is partly from the initial excitation, and partly from the ultrasonic guided wave excited in the liquid; with the propagation, the initially excited ultrasonic interface wave moves to the solid-liquid interface, forming the solid-liquid interface wave, and gradually leaks into the liquid; the ultrasonic guided wave in the liquid passes through the wall reflection of the pipeline every time, A new solid-liquid interface wave is formed at the solid-liquid interface, thus forming a group of solid-liquid interface waves with equal interval propagation. The density of liquid influences the energy distribution of interface wave: the higher the density of liquid, the more dispersed the energy of interface wave; the velocity of longitudinal wave of liquid influences the forming speed of solid-liquid interface wave: the faster the velocity of longitudinal wave, the faster the formation of solid-liquid interface wave. The research and analysis results can provide theoretical basis for pipeline damage detection.