Development of hybrid one-dimensional finite element/analytical method for analysis of lamb wave propagation characteristics in composit panels.

Abstract

The objective of this study is to develop a hybrid one-dimensional finite element (1-D FE)/analytical method to analyze the Lamb wave propagation characteristics of composite panels. Here, it is proposed to model a composite panel using a finite element approximation in the thickness direction while analytical solutions are assumed in the plane directions. Thus, it makes possible to use small number of finite elements even for high-frequency analysis in computationally efficient manner. By solving the eigenvalue problem of the resulting 1-D FE/analytical matrix equation, the dispersion relations of the Lamb waves propagating in the composite panel can be calculated in wave number/frequency domain. Note that the dispersion relations can be used to determine the frequency, wavelength, and wave speed of a specific Lamb wave mode that can be used to monitor the specific structural defects of the composite panel. For the purpose of validating the proposed method, the dynamic responses of a composite panel are measured. The measured data are transformed into wave number/frequency domain by applying spatial Fourier transform, which result in measured dispersion relations. It is shown that the dispersion relations obtained by using the proposed hybrid method agree well with the measured dispersion relations.