Optimization methods in design of locally resonant metamaterials for noise and vibration mitigation

Abstract

In recent years, acoustic metamaterials are broadly investigated especially for noise and vibration mitigation. For this purpose, the best-suited option are locally resonant metamaterials (LRS). By creation of a band gap effect in flexural wave propagation in structure, improve its Sound Transmission Loss (STL). The effectiveness of the structure in STL and vibration mitigation depends on several different parameters for example mass of the base structure to LRS mass ratio distances between resonators or its geometry. Many different shapes of LRS can lead to band gap for selected frequency range but with many different results when it comes to STL. Most of the solutions presented in recent years were based on simple beam resonators tuned to a selected frequency, and barely ever the geometrical optimization process of the resonator’s shape was considered. This project investigates optimization methods of the LRS presented in the literature, considering their efficiency and geometrical shape. Several algorithms were selected and combined with a numerical simulation process to obtain a solution with optimized mass and STL. Measurements for selected optimized structures are compared with simulation results and discussed in detail.