Accurate determination of dispersion curves of guided waves in plates by applying the matrix pencil method to laser vibrometer measurement data

摘要

Accurate knowledge of the dispersion relations of guided waves in plates is important for the efficient use of Lamb wave-based damage-detection methods. In this paper, we introduce a method which aims at automatically extracting the dispersion curves from laser vibrometer measurement data in an easy and robust manner. This method works by Fourier transforming the measurement data into the wavenumber domain and then applying the matrix pencil method by Hua and Sarkar to extract the wavenumber-dependent frequencies. As an additional result, we are able to experimentally detect backward propagating waves in aluminium plates.