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

这个项目的目标是利用微结构周期性材料的动态行为来精确定位声波的来源。 传统的声源位置识别方法是使用相控阵传感器，其精度受到传感器尺寸和声波波长的限制。本研究的目的是利用周期性复合材料的振动特性，以提高确定源的位置。 所开发的原理将直接应用于雷达和相关技术的国防和民用应用。 通过各种外展工作，这项研究将有助于扩大公众在波浪及其控制的高度多学科的主题的参与。水平排斥（LR）区是频率区域，在那里的状态的周期性微结构材料经历快速变化，以响应控制参数的微小变化，例如波的入射角。因此，它们可以用于精确测量其控制参数，例如，入射应力波的方位角。该项目的主要研究目标是：（a）确定声子本征值合并产生LR区的条件，并利用这一点证明声子晶体可以作为LR区附近的极其灵敏的方向传感器;（B）建立局部化灵敏度与LR区拓扑性质之间的关系，以创建调谐/通过PC的几何形状或材料特性的调制可调LR区;以及（c）为了创建实验室规模的声子晶体并证明LR区的存在，其次是在噪声和多频点环境中验证所开发的源定位方法的精度和鲁棒性。该奖项反映了NSF的法定使命，并被认为是值得的。通过使用基金会的知识价值和更广泛的影响审查标准进行评估来提供支持。

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.