非轴对称多元载荷条件下管道中纵向模态导波激励

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振动与冲击 ›› 2015, Vol. 34 ›› Issue (4) : 90-97.

论文

非轴对称多元载荷条件下管道中纵向模态导波激励

马书义，武湛君，刘科海，王奕首

作者信息 +

Longitudinal guided waves excited by non-axisymmetric multielement surface loading conditions in pipes

MA Shu-yi, WU Zhan-jun, LIU Ke-hai, WANG Yi-shou

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文章历史 +

摘要

轴对称载荷是管道中轴对称模态导波激励的有效方法。然而，受换能器安装误差等因素的影响，激励载荷多会变为非轴对称载荷，进而使激励出的导波模态变得复杂。对非轴对称多元载荷条件下纵向模态导波的激励问题进行了深入研究。考虑两种典型的非轴对称载荷，采用简正模态展开技术，建立了导波激励声场与边界载荷的量化关系，进而分析了各模态导波的产生机理及载荷阵列对纵向导波激励的影响。采用有限元数值模拟验证了理论预测结果。考虑实际管道检测中出现的非轴对称载荷，提出了一种载荷补偿策略并进行了实验验证。结果表明，该方法能够有效抑制弯曲模态导波的产生，同时也有助于改善导波信号的噪声水平。

Abstract

Axisymmetric surface loading is an effective method for exciting axisymmetric guided waves in pipes. However, non-axisymmetric surface loading is usually produced due to various influence factors such as transducer installation deviation, and result in the complexity of the excited guided wave modes. Longitudinal guided waves excited by non-axisymmetric multielement surface loading are investigated extensively. Two typical non-axisymmetric loading conditions are considered and analyzed. Based on the normal mode expansion technology, the quantitative relationship between applied boundary loadings and acoustic field is advanced, and then the generation mechanism of individual guided waves is analyzed and the effects of non-axisymmetric loading array on the generation of longitudinal modes are also discussed. Theoretical predictions are validated by the finite element simulations. For the non-axisymmetric surface loading occurred in the actual pipe inspection, a new loading compensation strategy is proposed and implemented. The results show that the compensation strategy can suppress the flexural modes effectively, and contribute to improve the noise floor of the guided wave signals.

导出引用

马书义;武湛君;刘科海;王奕首. 非轴对称多元载荷条件下管道中纵向模态导波激励[J]. 振动与冲击, 2015, 34(4): 90-97

MA Shu-yi;WU Zhan-jun;LIU Ke-hai;WANG Yi-shou. Longitudinal guided waves excited by non-axisymmetric multielement surface loading conditions in pipes[J]. Journal of Vibration and Shock, 2015, 34(4): 90-97