Direction-dependent elastic wave scattering and mode coupling in elastic plates

Asymmetric scattering is a phenomenon in which the field scattered from a discontinuity is dependent on the direction of incidence. In waveguide systems such as elastic plates, the existence of multiple propagating modes provides a platform to explore asymmetric scattering through direction-dependent mode coupling. In this talk, we first derive requirements for asymmetric scattering due to reciprocity and passivity in multi-mode systems. These principles are used in the design and modeling of an elastic beam containing a Willis scatterer which produces asymmetric coupling of symmetric and antisymmetric Lamb modes. Discrepancies between Euler-Bernoulli and Timoshenko beam modeling approaches are discussed.