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.
