LAUSR

Phononic crystals, capable of tailoring mechanical wave propagation and displaying omnidirectional bandgaps, are vital for numerous potential applications such as wave filtering, waveguiding, acoustic cloaking, and energy harvesting. In natural materials, vibration mitigation depending on the intrinsic damping feature usually cannot be readily adjusted and broad attenuation frequency ranges are still rare in these materials. Here, we propose an approach to design metamaterials with tunable vibration mitigation in multiple frequency ranges, which can be dynamically tuned by an external thermal field. The proposed method utilizes reversible Young's Modulus-temperature relationship of glassy polymers and nonuniformity of the steady temperature field in solid structures. Through numerical simulations and low amplitude transmission testing, we demonstrate that the proposed method and metamaterials can exhibit broad and multiple omnidirectional bandgaps. The finding reported here provides a routine to design phononic metamaterial systems with tunable bandgaps, offering a wide range of potential applications in harsh environmental conditions and being extended to baseline lattices with other topologies.