Bio-inspired heterogeneous composites for broadband vibration mitigation.

Yanyu Chen,Lifeng Wang

doi:10.1038/srep17865

Yanyu Chen, Lifeng Wang

Open Access

https://doi.org/10.1038/srep17865

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Abstract

Structural biological materials have developed heterogeneous and hierarchical architectures that are responsible for the outstanding performance to provide protection against environmental threats including static and dynamic loading. Inspired by this observation, this research aims to develop new material and structural concepts for broadband vibration mitigation. The proposed composite materials possess a two-layered heterogeneous architecture where both layers consist of high-volume platelet-shape reinforcements and low-volume matrix, similar to the well-known “brick and mortar” microstructure of biological composites. Using finite element method, we numerically demonstrated that broadband wave attenuation zones can be achieved by tailoring the geometric features of the heterogeneous architecture. We reveal that the resulting broadband attenuation zones are gained by directly superimposing the attenuation zones in each constituent layer. This mechanism is further confirmed by the investigation into the phonon dispersion relation of each layer. Importantly, the broadband wave attenuation capability will be maintained when the mineral platelet orientation is locally manipulated, yet a contrast between the mineral platelet concentrations of the two constituent layers is essential. The findings of this work will provide new opportunities to design heterogeneous composites for broadband vibration mitigation and impact resistance under mechanically challenging environmental conditions.

Highlights

Periodic structures and materials with spatially modulated elastic constants and densities have attracted intensive research interests due to their capabilities to manipulate the propagation of sound and heat
If the frequency is normalized by π = fa/2πct where a = 10 μ m is the lattice constant and ct = 75. 5 m/s is the transverse velocity of the matrix phase, the widths of attenuation zones in region I, II, and III are 1.05, 1.58, and 1.64, respectively. These findings indicate that broadband and enhanced wave attenuation capability can be readily achieved by designing the heterogeneous composites with two distinct constituent layers, leading to direct enhancements in vibration mitigation
It should be noted that the wave attenuation capability is progressively enhanced with the increase of the alignment angle from 0° to 90°. These results indicate that the proposed heterogeneous composites can maintain the broadband wave attenuation capability when the mineral platelet orientation is locally manipulated

Summary

Introduction

Periodic structures and materials with spatially modulated elastic constants and densities have attracted intensive research interests due to their capabilities to manipulate the propagation of sound and heat. Similar heterogeneous architectures have been observed in human teeth[34], consisting outer hard and brittle enamel layer and the relatively soft but tough dentin layer, and fish scale armor[35,36,37,38], which possess multiple mineralized layers where each layer is composed of a different nanocomposite material with varying structural and mechanical anisotropy. These natural design principles reveal the mechanisms responsible for the outstanding mechanical properties of structural biological composites, and provide us clues to design and develop high performance structural composites. The effect of local characteristics of the heterogeneous architecture on the wave attenuation capability is investigated

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