Reflection and Transmission of Structural Waves at an Interface Between Doubly Curved Shells

Reflection and transmission coefficients are derived for waves on doubly curved thin shells scattered by an interface of structural discontinuity. The coefficients are contained in an 8 × 8 S–matrix which describes all possible interaction modes between the 4 wave types on either side of the interface: quasi-longitudinal, quasi-shear, quasi-flexural, and quasi-evanescent flexural. The structural interface may be misaligned in the sense that the centroidal planes are displaced relative to one another, leading to mode mixing even for flat plate junctions. Some fundamental properties of the S–matrix are derived, including reciprocity and the fact that the sub-matrix associated with propagating (non-evanescent) shell waves is unitary.