Unusual behaviour of wave propagation in auxetic structures: P‐waves on free surface and S‐waves in chiral lattices with piezoelectrics

Abstract

We examine some unusual wave propagation characteristics related to auxetic systems represented by continuum isotropic materials and hexagonal chiral lattices with and without active piezoelectric actuation. We show for the first time a peculiar singularity in the ratio between reflected P and S waves in Rayleigh‐wave type propagation for auxetic isotropic materials, which has been otherwise observed only in at least bi‐phase material systems. The other unusual phenomenon is a strong increase of the pass‐stop band frequencies in hexachiral lattices with piezoelectric materials, with no change of the shear‐wave type otherwise occurring in pristine lattice with no piezoelectric contribution.

Thermodynamics of unconventional thermoelastic damping in auxetic media

“…The constitutive relations which deal with that phenomenon are (15) and (17). Then instead of the classical kinetic relation (26) we have Maxwell-Cattaneo's relation as the linear form of the evolution Eq. (6) [32,35,36]…”

Elastic properties of fcc crystals of polydisperse soft spheres

“…Understanding effects of various microscopic mechanisms on the Poisson's ratio of model systems is, amongst other reasons, important in the context of designing materials with anomalous (negative) Poisson's ratio. The latter materials were first manufactured more than two decades ago by Lakes () and have attracted considerable interest . They are often called auxetics (), which name, for its brevity, will be used in this paper.…”

Thermal Stresses in Thin Auxetic Plates

“…Auxetic systems have also been investigated for their performance as highly tunable molecular sieves or filters [35][36][37][38] and textiles and/or yarns [39][40][41][42][43][44][45][46], piezoelectric devices [47] and shape memory foams [48]. Plate structures that possess auxetic behavior have been studied.…”