Floquet–Bloch Waves in Periodic Networks of Rayleigh Beams: Cellular System, Dispersion Degenerations, and Structured Connection Regions

The paper is dedicated to Professor N. F. Morozov on the occasion of his 85th birthday. In the paper, we consider new dispersive properties of elastic flexural waves in periodic structures with rotational inertia. The structure is represented as a lattice with elementary bonds of Rayleightype beams. Although such beams in the semiclassical regime react as the classical Euler–Bernoulli beams, they exhibit new interesting characteristics as the dispersion frequency of flexural waves increases. Special attention is paid to degenerate cases related to the so-called Dirac cones on dispersion surfaces and to the directed anisotropy for the doubly periodic lattice. A comparative analysis accompanied by numerical simulation is carried out for the Floquet–Bloch waves propagating in periodic flexible lattices of different geometry.