Design, analysis, and fabrication of hybrid metastructures for acoustic-mechanical energy absorption based on origami helmholtz resonators

In all different engineering roles, ranging from building acoustics to transportation systems, the quest for efficient sound absorption structures with minimal thickness presents a constant challenge. This research introduces a novel approach to address this issue by proposing low-frequency sound-absorbent hybrid metastructures with sub-wavelength thickness. The two hybrid metastructures, based on embedded Helmholtz resonators, arrange the cavity walls in nested circular segments following the Miura origami pattern. The results demonstrate that the theoretical formulations and numerical simulations are in good agreement. After preparing the initial model, we investigated the sensitivity of geometric parameters and performed optimization to enhance acoustic performance. It was observed that the acoustic absorption coefficient of the metamaterial based on nested circular segments in the frequency range of 400-1000 Hz was calculated to be 0.85, while for the origami metamaterial in the frequency range of 400-900 Hz, it was calculated to be 0.80. Subsequently, we evaluated the mechanical energy performance of the optimized acoustic metastructure by conducting a compression test. A parametric study was carried out to assess the sensitivity of the mechanical energy absorption coefficient to the geometric parameters of the model. According to the results, the structure exhibited a mechanical energy absorption coefficient of 1.39 kJ/kg, which is favorable for mechanical energy absorption applications.