Elastic‐wave surfaces in solids

Abstract Based on Christoffel‐equation solutions, some interesting wave‐surface topological features are described for anisotropic media. These features include crossovers of transverse—longitudinal surfaces and continuous transverse—longitudinal mode conversion over a single surface. For orthorhombic symmetry (mmm), crossovers of transverse—transverse surfaces occur for all crystals: the transverse surfaces interconnect and form a single surface. Beyond this, some orthorhombic crystals exhibit a longitudinal—transverse crossover that causes all three surfaces to interconnect into a single surface. Crossover of longitudinal and transverse surfaces means that a transverse wave velocity will exceed a longitudinal wave velocity. A longitudinal—transverse mode conversion means that both longitudinal and transverse modes exist on the same wave surface.