Tunable mechanical diode of nonlinear elastic metamaterials induced by imperfect interface

Abstract

In this investigation, the non-reciprocal transmission in a nonlinear elastic metamaterial with imperfect interfaces is studied. Based on the Bloch theorem and stiffness matrix method, the band gaps and transmission coefficients with imperfect interfaces are obtained for the fundamental and double frequency cases. The interfacial influences on the transmission behaviour are discussed for both the nonlinear phononic crystal and elastic metamaterial. Numerical results for the imperfect interface structure are compared with those for the perfect one. Furthermore, experiments are performed to support the theoretical analysis. The present research is expected to be helpful to design tunable devices with the non-reciprocal transmission and diode behaviour of the elastic metamaterial.

Silver-mean canonical quasicrystalline-generated phononic waveguides

“…By recalling the analyses performed by Morini and Gei [17] and Gei et al [24], there are essentially three kinds of orbits which can be followed by points R i as a consequence of the iteration map ( 11): (i ) periodic orbits, (ii ) non-periodic bounded orbits and (iii ) escaping orbits. At any frequency ω, corresponding to a determinate Kohmoto's surface (16), the type of orbit is uniquely determined by the initial point R 0 = (x 0 , ỹ0 , z0 ) whose coordinates are given by expressions (12).…”

“…The requirements ( 17) and ( 18) can be fulfilled only for particular classes of layouts, namely the canonical (SM) layouts, in analogy to the definition proposed by Gei et al [24] for GM sequences. By substituting expressions (12) into condition (17), the following relationship between physical and geometrical properties of phases A and B are derived,…”

“…In the last twenty years, wave propagation in mechanical metamaterials and their applications in different areas of structural and mechanical engineering have attracted an increasing interest from the scientific community. Many different phononic composites and structures have been designed and tested with the aim of achieving and controlling several innovative dynamical phenomena, such as frequency filtering [1,2,3], wave focussing [4,5], cloaking [6,7], negative refraction [8,9,10] and non-reciprocal propagation [11,12].…”

Asymmetric full mode-converting transmission of elastic waves

“…Because of its scientific and technical significance, asymmetric wave propagation has attracted increasing attentions from researchers in various fields, covering acoustics [1], mechanics [2], elastics [3], photonics [4], thermal dynamics [5], and so on. In the acoustic/elastic field, many design strategies have been developed, by exploiting structural asymmetry [6,7], mode conversion [8,9], abnormal reflection and refraction [10][11][12][13][14][15][16][17][18], nonlinearity [19][20][21][22][23][24], time-space modulation [25,26], etc.…”

Nonlinear Rayleigh wave propagation in a layered half-space in dual-phase-lag

“…They are presently considered as an important component in science and technology due to their numerous applications as smart materials in intelligent microstructures in acoustic and vibration engineering, particularly in the field of acoustic filters and transducers, as well as advanced materials for noise control. Complex structures involving models of phononic crystals in linear or in nonlinear elastic media were explored in [1][2][3][4][5] on the basis of nonlocal theories in order to put in evidence the existence of frequency band gaps, wave energy distribution among the frequencies, effect of elastic nonlinearity and initial stresses, and the diode non-reciprocal transnission which prohibits wave propagation in certain directions.…”