• Mechanical Metamaterial and Smart Structures

    We investigate mechanical metamaterials and topological insulators, which show unparalleled wave transmission and acoustic bandgap.

  • Goal

    • 1.

      Design the mechanical metamaterials which shows the unparalleled advantages compared to existing materials

    • 2.

      Solve engineering challenges by exploiting and the novel property of the mechanical metamaterials

    Mechanical Metamaterials

    Fig. 1. (a) Unparalleled transmission of wave in elastic topological insulator. (b,c) Acoustic cloaking phenomenon.
    Total acoustic pressure field (b) with, and (c) without cloaking material.

  • Approach

    • 1.

      Design of Phononic Crystals, elastic or acoustic material with crystalline structure, possessing novel properties

    • 2.

      Numerical simulations of the wave propagation for demonstrating the desired properties

    • 3.

      Experimental verification of the simulated results

    • 4.

      Bandgap materials: Tuning the bandgap frequency for noise and vibration control

    • 5.

      Elastic topological insulator: Adoption of the solid-state physics to mechanical engineering

    Mechanical Metamaterials

    Fig. 2. (a) General research procedure of the mechanical metamaterials. (b) Tuning of the bandgap for acoustic bandgap materials.
    (c) Pseudospin nature of the elastic topological insulator.

  • Selected Publications

  • What is Mechanical Metamaterials?

    Metamaterial indicates the functional material designed to have a singular property that cannot be found in nature. Mechanical metamaterial means the metamaterial whose singular property is derived from its structure rather than its chemical composition. The potential of the mechanical metamaterial stems from that the singular property of the mechanical metamaterial can be designed or tuned nearly freely without any restriction thanks to the advancement of manufacturing technology. This huge degree of freedom in the design procedure resultingly enables the singular property to be novel in various engineering application fields. The focus of the mechanical metamaterials includes: (1) the exceptional value for conventional mechanical property such as negative mass density, negative Young’s modulus, and negative Poisson’s ratio (auxetic material); (2) time-varying, shape-morphing, and nonlinear metamaterials; and (3) topological metamaterials which were inspired by the topological phases in condensed-matter physics.