Pentamode metamaterials with ultra-low-frequency single-mode band gap based on constituent materials

Yan Huang; Xiaozhe Zhang

doi:10.1088/1361-648X/abeebd

Pentamode metamaterials with ultra-low-frequency single-mode band gap based on constituent materials

J Phys Condens Matter. 2021 Apr 23;33(18). doi: 10.1088/1361-648X/abeebd.

Authors

Yan Huang¹, Xiaozhe Zhang²

Affiliations

¹ School of Science, Xi'an Technological University, Xi'an 710021, People's Republic of China.
² School of Materials Science and Engineering, Xi'an Polytechnic University, Xi'an 710048, People's Republic of China.

PMID: 33721850
DOI: 10.1088/1361-648X/abeebd

Abstract

An effective method for realizing ultra-low-frequency single-mode band gap in pentamode metamaterials is proposed based on constituent materials. Results show that the decreasing ratioE/ρ(stiffness/mass density) of constituent material can significantly lower the frequency range of single-mode band gap. By merely replacing the constituent material from Al to rubber, the center frequencyf_cof single-mode band gap can be reduced nearly 600 times (from 3621 Hz to 6.5 Hz), while the normalized bandwidth Δf/f_cand the ratio of bulk modulusBto shear modulusGof pentamode structure keep substantially stable. The nonlinear fitting demonstrates that the relation betweenf_candE/ρsatisfies the logarithmic function. The two-component pentamode structure is designed to further explore the ultra-low-frequency single-mode band gap. The effects of thick-end diameterDof double-cone, diameterD₀and material type of additional sphere, on single-mode band gap of two-component system are analyzed. This work is attractive for several ∼Hz acoustic/elastic wave regulations using pentamode metamaterials.

Keywords: band gap; constituent material; pentamode metamaterials; ultra-low frequency acoustic/elastic wave.