Collaborative Research: Design and Reconfiguration of Curved Surfaces for Targeted Wave Propagation

这项拨款将资助研究，使声波通过工程或生物结构的自适应转向，应用于控制结构噪声，利用振动能量，诊断成像和植入医疗设备的无线能量传输，从而促进科学进步，促进国家繁荣。通过机械性能的复杂空间模式，材料可以设计成引导声波能量在理想的方向通过结构。这种材料可能很难制造，而且即使不是不可能，也很难实时修改。为了解决这些限制，该项目将研究依赖于弯曲的几何形状，薄弹性结构，以实现理想的波导效果，而不需要空间非均匀性，并具有自适应的按需可重构性的可能性。理论见解将与设计和制造的新工具相结合，以选择和制造几何形状赋予其特定声波特性的形状。旨在产生更广泛影响的活动包括为高中生和本科生提供研究经验和指导，以及为公众宣传和高中教师培训开发桌面动手演示。本研究旨在表征弯曲波在薄弯曲壳体上的传播特性，并确定如何利用变形壳体的几何形状来设计可调谐和实时自适应的声波导。它通过分析和数值计算、物理实验和创新制造技术的发展相结合来实现这些结果。声波在曲面上的几何透镜将根据各向异性、恒定或空间变化的厚度以及耦合膜状（面内）和弯曲（面外）运动的本构效应的影响进行分析，并特别关注通过消失的法曲率曲线的传播。将开发一种模块化的波导设计方法，其中可以实现精确的局部高斯曲率模式，以实现复杂的全局行为。最后，可重构性将通过在多个机械稳定形状之间切换来实现，包括由振动的共振特征模态激发引起的转换。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

This grant will fund research that enables the adaptive steering of acoustic waves through engineered or biological structures, with application to the control of structure borne noise, harnessing of vibrational energy, diagnostic imaging, and wireless energy transfer to implanted medical devices, thereby promoting the progress of science, and advancing the national prosperity. Through complex spatial patterning of mechanical properties, materials may be designed to guide acoustic wave energy in desirable directions through a structure. Such materials may be difficult to fabricate and challenging, if not impossible, to modify in real time. To address these limitations, this project will investigate reliance on the geometric shape of curved, thin elastic structures to achieve desirable waveguiding effects without the need for spatial inhomogeneity and with the possibility of adaptive on-demand reconfigurability. Theoretical insights will be combined with new tools for design and manufacturing to select and fabricate shapes whose geometry endows them with specific acoustic wave properties. Activities aimed at achieving broader impacts include research experiences and mentorship for high school and undergraduate students, as well as the development of table-top hands-on demos for public outreach and high school teacher training.This research aims to characterize flexural wave propagation on thin, curved shells and to determine how shape-morphing shell geometries can be used to design tunable and real-time adaptive acoustic waveguides. It accomplishes these outcomes through a combination of analytical and numerical calculations, physical experiments, and the development of innovative fabrication techniques. Geometric lensing of acoustic waves on curved surfaces will be analyzed in terms of the influence of anisotropy, constant or spatially varying thickness, and constitutive effects that couple membrane-like (in-plane) and flexural (out-of-plane) motion, with particular interest in propagation through curves of vanishing normal curvature. A modular approach to waveguide design will be developed in which precise patterns of localized Gaussian curvature can be realized to achieve complex global behavior. Finally, reconfigurability will be achieved by switching between multiple mechanically stable shapes, including through transitions induced by the excitation of resonant eigenmodes of vibration.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.