Owing to carrying rich information about structure flaws, broadband Lamb waves are considered as a promising tool for non-destructive testing. However, since every Lamb wave mode has its own dispersion characteristics, the feature extraction among broadband multimodal Lamb wave is challenging. Time–frequency representation is significantly effective to analyze dispersive signals. In this article, taking advantages of the idea of dispersion compensation, two kinds of time–frequency domain dispersion analysis methods for broadband Lamb wave were proposed. The first one is based on the concept of the general parameterized time–frequency transform. A kernel function related to group delay was designed and the time–frequency compensation transform was proposed. The other one combines the segment linear mapping technique and the short-frequency Fourier transform, called the time–frequency de-dispersion transform. Both these two methods work well in representing multimodal Lamb wave signals with high resolution. However, time–frequency de-dispersion transform outperforms in representing multipath Lamb waves than time–frequency compensation transform. Moreover, a mode purification strategy was also proposed for distinguishing the interested mode from interferences. According to verification in synthetic and experimental data, not only the multimodal components but also multipath echoes are represented in time–frequency plane with high resolution. Finally, the proposed method shows a great robustness to inaccuracies in the dispersion data.

由于携带了有关结构缺陷的丰富信息，宽带兰姆波被认为是无损检测的有前途的工具。但是，由于每种兰姆波模式都有其自身的色散特性，因此在宽带多峰兰姆波之间提取特征是一项挑战。时频表示法对于分析色散信号非常有效。本文利用色散补偿的思想，提出了两种宽带兰姆波时频域色散分析方法。第一个基于一般参数化的时频变换的概念。设计了与群时延相关的核函数，并提出了时频补偿变换。另一种结合了分段线性映射技术和短时傅立叶变换，称为时频解散变换。这两种方法都可以很好地表示高分辨率的多峰Lamb波信号。但是，在表示多径兰姆波时，时频解散变换的性能优于时频补偿变换。此外，还提出了一种模式净化策略，用于区分感兴趣的模式和干扰。根据对合成和实验数据的验证，不仅多模态分量而且多径回波都在时频平面中以高分辨率表示。最后，所提出的方法对色散数据的不准确性表现出很大的鲁棒性。这两种方法都可以很好地表示高分辨率的多峰Lamb波信号。但是，与时频补偿变换相比，时频解散变换在表示多径兰姆波上的表现要好。此外，还提出了一种模式净化策略，用于区分感兴趣的模式和干扰。根据对合成和实验数据的验证，不仅多模态分量而且多径回波都在时频平面中以高分辨率表示。最后，所提出的方法对色散数据的不准确性表现出很大的鲁棒性。这两种方法都可以很好地表示高分辨率的多峰Lamb波信号。但是，与时频补偿变换相比，时频解散变换在表示多径兰姆波上的表现要好。此外，还提出了一种模式净化策略，用于区分感兴趣的模式和干扰。根据对合成和实验数据的验证，不仅多模态分量而且多径回波都在时频平面中以高分辨率表示。最后，所提出的方法对色散数据的不准确性表现出很大的鲁棒性。与时频补偿变换相比，时频解散变换在表示多径兰姆波上的表现要好。此外，还提出了一种模式净化策略，用于区分感兴趣的模式和干扰。根据对合成和实验数据的验证，不仅多模态分量而且多径回波都在时频平面中以高分辨率表示。最后，所提出的方法对色散数据的不准确性表现出很大的鲁棒性。与时频补偿变换相比，时频解散变换在表示多径兰姆波上的表现要好。此外，还提出了一种模式净化策略，用于区分感兴趣的模式和干扰。根据对合成和实验数据的验证，不仅多模态分量而且多径回波都在时频平面中以高分辨率表示。最后，所提出的方法对色散数据的不准确性表现出很大的鲁棒性。