We demonstrate both numerically and experimentally that geometric frustration in two-dimensional periodic acoustic networks consisting of arrays of narrow air channels can be harnessed to form band gaps (ranges of frequency in which the waves cannot propagate in any direction through the system). While resonant standing wave modes and interferences are ubiquitous in all the analyzed network geometries, we show that they give rise to band gaps only in the geometrically frustrated ones (i.e. those comprising of triangles and pentagons). Our results not only reveal a new mechanism based on geometric frustration to suppress the propagation of pressure waves in specific frequency ranges, but also opens avenues for the design of a new generation of smart systems that control and manipulate sound and vibrations.
Welcome to the Bertoldi Group at Harvard University. In our research, we combine theoretical, computational and experimental methods to gain deeper insight into the non-linear behavior of materials and structures. Guided by theoretical and numerical analysis, we exploit material and geometric non-linearities to design novel materials with tunable exceptional properties, and we seek to create and test such materials. Read more about some of our recent and ongoing research projects in the Research section.