Novel Solitonic Waveguides Based on Granular Phononic Crystals

该奖项的研究目标是模拟和测量二维颗粒光波导中声孤子的形成。PI将设计和制造包含在窄通道中的六角形填充颗粒晶格，其定义为颗粒声子晶体。PI将揭示组装的颗粒结构中独特的孤子形成和传输机制。对孤子传播的基本理解将使一类新的能够以可控和有效的方式过滤、延迟和重定向声孤子的波导成为可能。PIS将通过开发先进的离散元素模型(DEM)和新的数字图像相关(DIC)技术来实现这一研究目标。基于分子动力学技术，DEM将在充分考虑紧密堆积的摩擦粒子的轴向和旋转动力学的情况下模拟孤子的传播。PIS将通过DIC技术在高采样率下测量极小的颗粒位移来验证数值模拟结果。从物理学的角度来看，本研究的发现将有助于基于颗粒动力学的拉格朗日描述的颗粒介质非线性力学的发展。从潜在的工程应用的角度来看，制作的孤子波导可以通过利用增加的自由度来控制机械波，从而在机械波滤波、声成像和无损评估方面开辟一种新的范式。除了对科学和工程做出贡献外，研究活动还将对学生的教育产生更广泛的影响。PIS将通过南卡罗来纳大学(USC)的学生服务和项目招收和培训代表不足的学生。从这项工作中获得的知识和产品将整合到南加州大学新的航空航天工程研究生课程中。

The research objective of this award is to simulate and measure the formation of acoustic solitons in two-dimensional granular waveguides. The PIs will design and fabricate hexagonally packed granular lattices "defined as granular phononic crystals" contained in a narrow channel. The PIs will unveil unique soliton formation and transmission mechanisms in the assembled granular architectures. The fundamental understanding of soliton propagation will enable a new class of waveguides that can filter, delay, and redirect acoustic solitons in a controllable and efficient manner. The PIs will achieve this research goal by developing an advanced discrete element model (DEM) and a novel digital image correlation (DIC) technique. Based on molecular dynamics techniques, the DEM will simulate the propagation of solitons under the full consideration of axial and rotational dynamics of tightly packed, frictional particles. The PIs will verify the numerical simulation results by the DIC techniques that measure extremely small particle displacements at high sampling rates.From the viewpoint of physics, the findings in this study will contribute to the advancement of nonlinear mechanics of granular media based on the Lagrangian description of particle dynamics. With a view towards potential engineering applications, the fabricated solitonic waveguide can open a new paradigm in mechanical wave filtering, acoustic imaging, and nondestructive evaluation by leveraging an added degree of freedom in controlling mechanical waves. Besides contributing to science and engineering, the research activities will also have a broader impact on educating students. The PIs will recruit and train underrepresented students via student services and programs at the University of South Carolina (USC). The knowledge and product obtained from this work will be integrated into the new graduate program in aerospace engineering at USC.