EAGER: Acoustic Diode as Architectural Material (ADAM)

噪音是最狡猾的污染形式，因为它对人体健康的影响被低估了。暴露在噪音中可能会损害神经系统，引发压力和睡眠障碍，并可能导致心脏问题和高血压。人们几乎在任何地方都接触到噪音。出于这个原因，工程师和建筑师努力创造有效和精细的解决方案来减轻室内产生的噪音，以提高居住者的舒适度，提高工作场所的人员效率，保证隐私，并提供无干扰的空间。考虑到这一社会问题，这个早期概念探索研究基金（EAGER）项目将探索一个新的建筑系统，基于声学二极管作为音障的概念。这一迫切需要的结果将使我们能够进行一项全面的研究，以解决影响很大一部分人口的社会问题。此外，该项目将对建筑和结构工程感兴趣，并将在许多方面产生影响，包括：(1)一些不同学科的交叉授粉，如声学，非线性动力学和建筑工程；(2)监督具有计算和实验技能的各类学生；(3)将研究成果融入多学科教育计划，培养高年级本科生、专业硕士和研究生；(4)外展和传播活动，告知学术界、专业工程师、专业人士和一些普通的年轻受众，使用声学超材料的新概念设计更好的声学屏障的经济和社会影响。就像它们的电子对应物一样，声学二极管在一个方向上对声音的电阻低，而在相反的方向上对声音的电阻高。换句话说，声学二极管提供了阻止声音沿一个方向传播的机会。这项研究的假设是，嵌入在新型建筑材料中的二极管可以按多种长度缩放，以屏蔽室内噪声，最终屏蔽过境产生的噪声。新的隔音屏障将由三个元素组成：一个膜，一个由带有入侵者的球形颗粒的一维链组成的声学二极管，和一个板。这个想法是要屏蔽的噪音到达墙壁并在膜中转化为振动。这种振动触发沿二极管的非线性孤立波的形成和传播，在那里它们被捕获并在多次反射的影响下衰减。这个项目的优点在于对基本物理概念的研究，这将导致一种新型建筑隔音屏障的发展。

Acoustic noise is the slyest form of pollution because its effects on the human health are underestimated. Exposure to noise may hamper the nervous system, trigger stress and sleep disorder, and may cause heart problems and high blood pressure. People are exposed to noise almost anywhere. For this reason engineers and architects strive to create effective and fine solutions to mitigate indoor-generated noise in order to enhance the comfort of the occupants, improve personnel efficiency in the workplace, guarantee privacy, and to provide distraction-free spaces. With this societal problem in mind, this EArly-concept Grant for Exploratory Research (EAGER) project will explore a new architectural system, based on the concept of acoustic diode acting as a sound barrier. The outcome of this EAGER will enable to carry out a comprehensive study that will address a societal issue that impacts a large fraction of the human population. Additionally, the project will be of interest for architectural and structural engineering, and will be impactful in many ways including the: (1) the cross-pollination of a few different disciplines such as acoustics, nonlinear dynamics, and architectural engineering; (2) supervision of a diverse pool of students with skills in computation and experimentation; (3) integration of the research findings into a multidisciplinary education program to engage senior undergraduates, professional M.S. and graduate students; (4) outreach and dissemination activities to inform the academic community, professional engineers, professionals and some general young audience of the economic and societal impacts of designing better acoustic barriers using the novel concepts of acoustic metamaterials. Like their electrical counterpart, acoustic diodes offer low resistance to sound in one direction and high resistance in the opposite direction. In other words, acoustic diodes offer the opportunity to forbid sound transmission along one direction. The hypothesis of this research is that a diode, embedded in the novel architectural material, can be scaled at multiple lengths to shield indoor noise and eventually transit-generated noise. The new noise barrier will be composed of three elements: a membrane, an acoustic diode made of 1-D chains of spherical particles with intruders, and a plate. The idea is that the noise to be shielded reaches the wall and is converted into vibration in the membrane. This vibration triggers the formation and propagation of nonlinear solitary waves along the diode where they are trapped and decay by the effect of multiple reflections. The merit of this project lies in the investigation of the fundamental physical concepts that will lead to the development of a novel architectural noise barrier.