Adaptable Wave Propagation In Phononic Structures Via Origami Folding

origami kinematics;acoustic wave propagation;phononic bandgaps;scattering theory;Mechanical Engineering;Engineering;Mechanical Engineering

Thota, ManojPerkins, Noel C ;

University of Michigan

关键词: origami kinematics;    acoustic wave propagation;    phononic bandgaps;    scattering theory;    Mechanical Engineering;    Engineering;    Mechanical Engineering;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/140952/mthota_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Wave propagation inside a fluid-media with periodically distributed solid-inclusions (viz. phononic structures) exhibit bandgaps, which are frequency regions in transmission spectra where wave propagation is attenuated. Controlling acoustic bandgaps have many engineering applications such as in sound barriers, acoustic signal processing elements and infra-ultra sound imaging systems; and incidentally, phononic structures that can control wave propagation in terms of band structure provide an excellent base for such applications. In spite of the diverse technical studies on the effect of geometric parameters of phononic structures on wave propagation, research on broadband acoustic bandgap adaptation that will have large impact on the abovementioned engineering applications is still outstanding. One of the important geometric properties in ABG design is the lattice-type – five different 2D (two-dimensional) Bravais lattices (rectangle, square, hexagon, centered rectangle and oblique) are classified based on their symmetry properties. It is possible that by reconfiguring periodicity of phononic structures between distinct lattice-types, where each lattice-type exhibit fundamentally different dispersion relations, we may achieve broadband wave tuning. In this spirit, to advance the state of the art, this thesis pioneers a new class of reconfigurable phononic structures that utilizes origami folding to reconfigure the periodicity of lattice and achieve significant phononic bandgap adaptation. The design of origami phononic structure is composed of cylindrical inclusions attached to the vertices of Miura origami sheet. It is found that origami folding, which can enable significant and precise topology reconfigurations in the lattice of inclusions between distinct Bravais lattice-types, can bring about drastic changes in waves propagating through phononic structure. Such versatile wave transmission control is demonstrated by extracting band structure of waves propagating in the plane perpendicular to the inclusions axis. Further, numerical and experimental simulations performed on finite origami structure demonstrate that wave propagation can be significantly changed in terms of bandgaps. Major contributions, impacts and uniqueness of this research•A reconfigurable origami architecture is proposed that can transforms the underlying periodicity between distinct symmetry Bravais lattices. Unlike previous theoretical studies that rely on symmetry reduction techniques to change bandgaps, here through origami folding, the symmetry of the lattice is shifted between different point groups that leads to drastic adaptation in bandgaps. To study the effect of such reconfiguration on wave propagation, a numerical model is developed that combines origami folding kinematics with wave propagation theory.•We utilize the versatile wave tailoring capabilities of origami structures to advance unique wave control mechanisms such as (a) traffic noise mitigation (b) tunable waveguiding and (c) adaptive unidirectional transmission via achieving broadband tailoring in their frequency spectra. These unique adaptable wave control mechanisms are demonstrated via analytical, numerical and experimental investigations. The outcomes and findings of this research are useful to engineering applications such as traffic noise barriers and acoustic filters, especially under system uncertainties and variations.•Being a one degree of freedom, the origami rigid-folding mechanism used for lattice reconfiguration, can achieve global topology transformation and the bandgap adaptation via minimal local actuation.Further, since the related folding principle is scale independent, origami can be fabricated at vastly different scales to target different frequency ranges. For example, due to the equivalence in wave equation of sound and light, the phononic crystal design proposed in this thesis can also be used to use to build photonic crystal and manipulate light wave propagation.