Spider web-inspired acoustic metamaterials

Abstract

Spider silk is a remarkable example of bio-material with superior mechanical characteristics. Its multilevel structural organization of dragline and viscid silk leads to unusual and tunable properties, extensively studied from a quasi-static point of view. In this study, inspired by the Nephila spider orb web architecture, we propose a design for mechanical metamaterials based on its periodic repetition. We demonstrate that spider-web metamaterial structure plays an important role in the dynamic response and wave attenuation mechanisms. The capability of the resulting structure to inhibit elastic wave propagation in sub-wavelength frequency ranges is assessed, and parametric studies are performed to derive optimal configurations and constituent mechanical properties. The results show promise for the design of innovative lightweight structures for tunable vibration damping and impact protection, or the protection of large scale infrastructure such as suspended bridges. Published by AIP Publishing. [http://dx

Propagation of elastic solitons in chains of pre-deformed beams

“…This study represents the first step towards the investigation of large amplitude waves in beam lattices in 2D and 3D. While periodic lattices have recently attracted considerable interest because of their ability to tailor the propagation of linear elastic waves through directional transmissions and band gaps (frequency ranges of strong wave attenuation) [39][40][41][42][43], comparatively little is known about their nonlinear behaviors under high-amplitude impacts [20]. The results presented in this paper provide useful guidelines for future explorations of the propagation of nonlinear waves in lattice materials.…”

Reversible signal transmission in an active mechanical metamaterial

“…Our study introduces a theoretical biologically inspired mechanism that automatically resets each element to a high potential energy state, allowing the transmission of further signals. Many recent studies introduce the idea of manipulating biological subsystems in materials [22][23][24], or discuss behaviours that arise in active matter systems, where biological systems exert mechanical forces [25]. Some systems are biologically inspired [21,23,24] where properties of the metamaterial are designed to mimic a biological phenomenon, and some systems exploit the properties of biological subsystems to produce new behaviours in the material [22].…”

Acoustic waveguide filters made up of rigid stacked materials with elastic joints

“…In this case, low-frequency band gaps may be obtained, even if heavy resonators and low stiffness cells are required to get wide stop-bands. Improvements in creating wide low frequency band gaps have been obtained by virtue of the concept of effective inertia, consisting in amplifying a small mass through embedded amplification mechanisms (see Yilmaz et al, 2007, Acar and Yilmaz, 2013, Taniker and Yilmaz, 2015, Frandsen et al, 2016 or by mimicking biological structural systems (see Miniaci et al, 2016 andMiniaci et al, 2018). Recently, Yin et al, 2014, and Chen and Wang, 2015, obtained ultra-wide lowfrequency band gaps in composites designed on the thought of staggered and combined soft and hard materials.…”