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• The out-of-plane resonant stiffness difference is introduced to break the space inversion symmetry. • The nontrivial nature of the discrete spring-mass lattice model is verified via both theoretical and numerical investigation. • This symmetry-breaking configuration can be extended to the continuum plate-resonator model successively. • The programmable topological interface path is realized by using the asymmetric effective stiffness of the bistable structure between tension and compression. Topological metamaterials provide a new strategy to guide wave energy and exhibit unprecedented robustness. In this study, a novel design strategy is proposed to realize programmable topological metamaterials with local resonant eigenstates. Firstly, in the discrete spring-mass model, two resonant masses and two base masses are introduced into the hexagonal lattice, and a local resonant eigenstate-induced Dirac cone can be formed at the high symmetry point of the Brillouin zone. By introducing the spring stiffness difference, a topological bandgap is opened near the Dirac degeneracy frequency. Thereafter, the nontrivial nature of the bandgap is verified by the theoretical evaluation of the Berry curvature and Chern number. Secondly, the symmetry-breaking configuration is extended to a continuum plate-resonator model. The numerical results demonstrate that the interface state wave propagates along the interface path at a frequency located at the edge-bulk band. Finally, by using the asymmetric effective stiffness of the bistable structure between tension and compression, a programmable topological interface path is realized. The proposed reconfigurable design based on asymmetry significantly expands the design space of metamaterials. [ABSTRACT FROM AUTHOR]

Metamaterials/Phononic crystals are used to control the propagation of elastic waves/sound waves, and can be used in fields such as vibration isolation, noise reduction, stealth, focusing, and acoustic wave devices. The realization of real-time, flexible and active adjustable control of elastic waves by mechanical reconstruction of metamaterials is a current research hotspot. Here, SMP metamaterials with mechanical reconstruction and self-recovery ability are proposed. Affected by the glass transition temperature of the material, the mechanical properties of the metamaterials are related to the geometric parameters of the lattice configuration and the external temperature. The metamaterials can adaptively switch mechanical properties and shapes without continuous external excitation of the physical field. The finite element method and experiments were used to analyze the deformation and self-recovery process of the metamaterials. The results show that the metamaterial can achieve mechanical programming and response recovery, and the bandgap of the metamaterial can be greatly adjusted by changing the external temperature. Unlabelled Image • The Shape memory polymer (SMP) metamaterials with mechanical reconstruction and self-recovery ability are proposed. • FEA and experiments were used to analyze the deformation and self-recovery process of the metamaterials. • The metamaterial can achieve mechanical programming, response recovery and adjust the band gap. [ABSTRACT FROM AUTHOR]