超声导波的频散补偿与模式分离算法研究

Dispersion compensation and mode separation of the ultrasonic guided waves

超声导波已被广泛应用于无损检测与评价,针对超声导波应用中普遍存在的模式混叠与频散问题,本文在采用频谱相位与信号时延函数建模导波频散信号传递系统的基础上,提出了一种单一模式的频散补偿算法。进一步地,通过将选择性频散补偿技术与导波模式分离相结合,本文算法克服了传统补偿算法所不能解决的多模式导波频散问题。板中的Lamb波A_0,A_1和S_0混合模式仿真分析表明,本算法不仅可用于单一导波模式信号合成与频散补偿,而且可在实现多模式混合导波信号选择性频散补偿基础上,解决多模式导波信号中单一模式提取与分离。本文研究有助于超声导波多模式频散信号的分析与处理.

The application of ultrasonic guided waves has been got considerable attentions in non-destructive evaluation （NDE）. However, the mode overlap and dispersion problem of guided waves are still challenging. In the present study, we used the spectral phase and time delay function to model the guided dispersion transfer system, and developed a compensation algorithm of single mode dispersion. Aiming to overcome the unsolved difficulty of multimode processing, dispersion compensation was then combined with the mode separation. Simulations of the Lamb modes A0, A1 and So illustrated that the proposed algorithm is capable of synthesizing and compensating of single mode dispersion. Furthermore, using the selectively compensation, the individual modes can also be extracted from the multimodal guided signals. The study is helpful for the signal processing of multimodal guided dispersion.