Functionality enhancement in disordered metamaterial systems: the case of bandgap widening*

The dominant approach in the design of mechanical metamaterials revolves around ordered arrangements of mesoscale constituents---e.g. resonating units in the context of wave and vibration control. In this work, we unveil through experiments a family of unique effects that challenge this paradigm and are directly enabled by the interplay between the mechanical heterogeneity and the spatial disorder of the resonators population. The experiments are carried out using reconfigurable specimens with telescopic pillars whose resonant characteristics can be agilely and intuitively tuned through simple manual operations. In particular, we demonstrate that spatial disorder can be leveraged to enhance the already remarkable broadband filtering capabilities of so-called rainbow materials, and we provide a physical rationale for this bandgap widening phenomenon.