Broadband and multiband vibration mitigation in lattice metamaterials with sinusoidally-shaped ligaments

Engineering the architectures of materials is a new approach to obtain unusual properties and functionalities in solids. Phononic crystals with periodically architected microstructures and compositions exhibit omnidirectional phononic band gaps, offering a unique capability to steer mechanical wave propagation. The coupled architecture-material design strategy, however, poses a significant challenge to design phononic crystals with broadband and multiband vibration control capabilities. Here we propose and demonstrate a new metamaterial design concept in which symmetry-broken ligaments with ordered topology are taken as the constitutive elements for regular lattice materials. Through integrative computational modeling, 3D printing, and vibration testing we demonstrate that the proposed lattice metamaterials can exhibit broad and multiple omnidirectional band gaps over a wide range of the geometry parameters that define the ligament. We show that the designed microstructure of the lattice metamaterial is robust and can be extended to baseline lattices with other topologies.