Scattering of guided shear waves in plates with discontinuities

This paper investigates the interaction of the SH0 mode with discontinuities in plate waveguides. The scattered fields are evaluated using a novel method that exploits the principle of reciprocity in elastodynamics. The results obtained compare to those provided by a finite element model. Very good agreement between the analytical and numerical models proves the effectiveness of the proposed approach, enabling us to clearly elucidate the role of the different size and shape parameters involved. The discontinuities considered are single and double sharp reductions of plate height of different amounts and lengths, where both symmetric and nonsymmetric one-sided notch cases are treated. Regimes related to low and high values of the product frequency and height of the plate are investigated, showing the dependence of reflection and transmission coefficients on length and height of the discontinuity, as well as the occurrence of mode conversion. The analytical approach proposed leads to a better understanding of the interaction of guided waves with discontinuities, which may stimulate the application of guided waves to defect sizing rather than to simple detection.