Instabilities in highly deformable systems: unique opportunities for control of flow and vibrations

具有调谐不稳定性的新型主动器件是从柔性结构的激励领域中出现的，用于致动器、自适应系统和自调节流体学的设计。然而，现有的表征技术仅限于传统材料和有前途的功能仍有待探索。本课题是K. Bertoldi（哈佛大学）的目标是利用非线性结构的最新研究成果，加深我们对现代材料的理解和科学分类，并扩展各种环境中调谐不稳定性的应用领域。可逆、剧烈压实的独特机会允许覆盖软结构、压实材料以及两者之间的混合物。这种统一的方法扩展了传统的表征技术（如非破坏性参数识别，临界频率的预测），以新颖的structure.In子项目II，非线性谐振器嵌入应变控制屈曲单元。局部谐振器的频谱丰富度由可展开单元结构的屈曲来调节，从而产生具有各种可调谐衰减制度的新功能超材料。最有前途的几何形状的数值和实验测试将证明优化设计的鲁棒性和适用性。

A novel class of active devices with tuned instabilities is emerging from the exciting field of compliant structures for the design of actuators, adaptive systems, and self-regulating fluidics. Yet, available characterization techniques are restricted to conventional materials and promising functionalities remain to be explored. This research project at the research group of K. Bertoldi (Harvard University) aims at exploiting latest research on non-linear structures to sharpen our understanding and scientific classification of modern materials and to extend the application areas of tuned instabilities in various environments.In subproject I, the dynamic processes in fluid-filled, highly deformable structures are simulated and related to geometric and material properties. The unique opportunity of reversible, drastic compaction allows to cover soft structures, compact materials, and hybrids in between. This unifying approach extends conventional characterization techniques (e.g. nondestructive parameter identification, prediction of critical frequencies) to novel structures.In subproject II, non-linear resonators are embedded in strain-controlled buckling cells. The spectral richness of local resonators is regulated by the buckling of the deployable cell structure, yielding a new functional meta-material with various tunable attenuation regimes. Numerical and experimental tests of the most promising geometries will prove the robustness and applicability for an optimized design.