Lightweight decorated membranes as an aesthetic solution for sound insulation panels

The need for energy-efficient vehicles and machines often drives performance design towards mass reduction, harming noise and vibration. Metamaterials are recently being studied as a possible solution to tackle this classical acoustic problem with reduced mass and promising attenuation, at least in narrow frequency bands. This work presents a solution based on variations of the so-called decorated membrane acoustic metamaterial (MAM) by assembling membranes of different shapes and sizes into a supercell. Tessellation concepts are used to ensure the geometric compatibility between each component and the periodicity of the supercell. Finite element models are derived to estimate unit cells' sound transmission loss performance, experimentally validated on a transmission loss tube. Finally, full MAMs panels are conceived based on the validated models, showing an attenuation band formation around the membranes' mass-dominated frequencies, thus realising a metamaterial that can outperform the mass law.

Automated summary

The need for energy-efficient vehicles and machines often leads to the reduction of mass, which in turn affects noise and vibration. Metamaterials, particularly decorated membrane acoustic metamaterials (MAM), have shown promising results in reducing mass and providing efficient attenuation in narrow frequency bands. This study proposes a solution by assembling membranes of different shapes and sizes into a supercell, using tessellation concepts to ensure geometric compatibility and periodicity. Finite element models are used to evaluate sound transmission loss performance of unit cells, which are experimentally validated. Finally, full MAM panels are designed based on the validated models, showing attenuation band formation around the membranes' dominant frequencies and surpassing the mass law.