Preliminary study of reuse of plastic bottles as metamaterial

The present work introduces a novel approach to designing metamaterial for low frequency and high frequency wave attenuation by repurposing plastic waste. The metamaterial is constructed using a duct-like structure with a periodic arrangement of bottles of different sizes. This configuration leads to the formation of a local resonant band, which spans from 240 to 340 Hz. In both the numerical model and the experimental setup, a harmonic excitation is given to the proposed configuration and transmission loss is computed as a function of frequency. The experimental results support the findings obtained from numerical simulations, confirming the effectiveness of the designed metamaterial. One crucial aspect discovered in this work is that introducing space between the bottle’s neck and the side wall of the structure causes the bottles to act as Helmholtz resonators. Thus, in turn, this results in an additional band gap at low frequencies, complementing the existing Bragg’s band gap achieved by the periodic arrangement of bottles. The ability to change the size of the bottles gives control over the position of the band gap, allowing for greater flexibility in tailoring the metamaterial to specific noise attenuation requirements. The applications of these plastic bottle-based metamaterials are wide ranging, especially in improving the indoor acoustic environment of buildings. This work opens up a new avenue for further exploration and innovation in the field of sustainable and environmentally friendly metamaterials.