2013/11/05 by J.R. Willis, Willis, John
Engineering · #Acoustic Wave Phenomena Research #Elasticity and Wave Propagation #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Structural Analysis and Optimization
paper · pdf · doi:10.48550/arxiv.1311.3875
openalex publication_date 2013/11/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The main purpose of this work is to address the question of the utility of "effective constitutive relations" for problems in dynamics. This is done in the context of longitudinal shear waves in an elastic medium that is periodically laminated, with attention restricted to plane waves propagating in the direction normal to the interfaces. The properties of such waves can be found by employing Floquet theory, implemented via a "transfer matrix" formulation. Problems occur at frequencies beyond those that define the first pass band, associated in part with the difficulty of assigning a unique wavenumber to the wave. This problem is examined, paying careful attention to the requirements of causality and passivity. The transmission of waves into a half-space is discussed by studying the impedance of the half-space, both directly and in the "effective medium" approximation, and an alternative way of looking at this problem, based on construction of the Green's function, is developed.