Abstract

Conventional noise control solutions used in the transportation industry have proven to be effective in minimizing structure-borne sound at mid to high frequencies; however, a lightweight means to control low-frequency structure-borne sound remains elusive. Recent advancements in additive manufacturing technologies have enabled researchers to develop novel acoustic metamaterial concepts capable of reducing low-frequency structure-borne sound. This work presents a methodology to numerically model and optimize an acoustic metamaterial to facilitate the development of more advanced acoustic metamaterial concepts. The investigated acoustic metamaterial consists of a periodic structure embedded with resonant inclusions that are tuned to resonate out of phase with the host structure causing an attenuation in surface vibrations. First, a numerical model of the metamaterial is created using the finite element method to generate mass and stiffness matrices for a honeycomb sandwich structure. Second, the system matrices are reduced using the Craig-Bampton Method, which are then modified to include the contribution of tuned vibration absorbers as resonant inclusions. Subsequently, the particle swarm optimization strategy is employed to optimize the mass, stiffness and damping properties of the tuned vibration absorbers to minimize the RMS surface velocity over a specified frequency range. Overall, the acoustic metamaterial exhibits a strong ability to reduce the RMS surface velocity within an optimized frequency range indicating reduced structure-borne sound emission compared to conventional honeycomb structures.

摘要

运输行业使用的传统噪声控制解决方案已被证明可有效减少中高频的结构声；然而，控制低频结构声的轻量级方法仍然难以捉摸。增材制造技术的最新进展使研究人员能够开发出能够减少低频结构声的新型声学超材料概念。这项工作提出了一种对声学超材料进行数值建模和优化的方法，以促进更先进的声学超材料概念的开发。所研究的声学超材料由嵌入共振夹杂物的周期性结构组成，共振夹杂物被调谐为与主体结构异相共振，从而导致表面振动衰减。第一的，使用有限元方法创建超材料的数值模型，以生成蜂窝夹层结构的质量和刚度矩阵。其次，使用 Craig-Bampton 方法减少系统矩阵，然后对其进行修改以包括调谐减振器作为共振夹杂物的贡献。随后，采用粒子群优化策略来优化调谐减振器的质量、刚度和阻尼特性，以最小化指定频率范围内的 RMS 表面速度。总体而言，声学超材料表现出在优化频率范围内降低 RMS 表面速度的强大能力，表明与传统蜂窝结构相比，结构声发射减少。