Collaborative Research: Accurate Determination of Acoustic Wave Sources using Periodic Microstructured Materials

该项目的目标是利用微结构周期性材料的动力学行为来精确定位声波的源。传统的声源定位方法是使用相控阵传感器，与声波的波长相比，相控阵传感器的精度受到传感器尺寸的限制。这项研究的目的是利用周期性复合材料的振动特性来提高震源位置的确定。开发的原理将直接应用于雷达和相关技术在国防和民用方面的应用。通过各种外展工作，这项研究将有助于扩大公众对波及其控制这一高度多学科的学科的参与。水平斥力(LR)区是周期性微结构材料的状态随着控制参数(如波的入射角)的微小变化而经历快速变化的频率区域。因此，它们可以用来精确测量它们的控制参数，例如，入射应力波的方位角。这个项目的主要研究目标是：(A)确定声子本征值聚集产生LR区的条件，并利用这一条件证明声子晶体可以在LR区附近充当极其灵敏的方向传感器；(B)建立局域化敏感性与LR区的拓扑性质之间的关系，以便通过对PC的几何或材料性质的调制来创建可调/可调的LR区；以及(C)创造实验室规模的声子晶体并证明LR区的存在，然后验证所开发的源定位方法在噪声和多源环境中的精确度和稳健性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The goal of this project is to exploit the dynamic behavior of microstructured periodic materials to accurately locate the sources of sound waves. The traditional method of identifying source location is using phased array sensors whose precision is limited by the size of the sensor in comparison with the wavelength of acoustic waves. This research will aim to use the vibrational properties of periodic composites to improve determination of source location. The principles developed will have direct application to radar and associated technologies in both defense and civil applications. Through various outreach efforts, this research will help in broadening the participation of the public in the highly multi-disciplinary subject of waves and their control.Level Repulsion (LR) zones are frequency regions where the state of a periodic microstructured material undergoes rapid change in response to minute changes in a controlling parameter, e.g. wave incidence angle. Therefore they may be utilized for precise measurement of their controlling parameter, for example, the bearing angle of an incident stress wave. The principal research objectives of this project are: (a) To determine the conditions under which phononic eigenvalues coalesce to give rise to LR zones and to exploit this to demonstrate that phononic crystals can act as extremely sensitive directional sensors near LR zones; (b) To establish the relationships between the sensitivity of localization and the topological properties of LR zones in order to create tuned/tunable LR zones through modulations in the geometry or material properties of the PC; and (c) To create lab-scale phononic crystals and demonstrate the existence of LR zones, followed by verification of precision and robustness of the developed source localization methods in noisy and multisource environments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.