Wave boundary element to study Lamb wave propagation in plates

By using analytical mode shapes as the interpolating functions for both displacements and stresses on the reference edges of a plate, a wave element is formulated for use in the boundary element method to study Lamb wave propagation and interaction in plates, to achieve both accuracy and computational efficiency. Lamb wave interaction with a notch is investigated using this method. The results with respect to wave transmission, reflection and mode conversion are consistent with physical considerations of Lamb mode shape and energy conservation. It is shown through the reflection coefficients that S0 Lamb wave is more sensitive than A0 wave for detecting a shallow notch in a plate. These coefficients can be used to aid the characterization of the presence of a notch and contribute to quantitative non-destructive evaluation methodology for plate structures. Time history results are obtained by conducting Fourier transform on the coefficients solved in frequency domain. Comparison with experiment results shows the suitability of the method for wave propagation studies in relation to damage detection.