Mechanical metamaterials are artificially structured materials designed to exhibit properties not found in naturally occurring materials, such as negative Poisson’s ratio, negative thermal expansion, negative stiffness, negative mass density, and programmable properties. These properties are typically achieved by engineering the material’s internal structure at a micro or nanoscale, rather than by altering its chemical composition. We design active mechanical metamaterials and establish a general physical theory of these designed structures. We design (active) mechanical metamaterials and establish a general physical theory of these designed structures.

Fundamental Research (Engineering Mechanics)

1. Meta-statics: We identify and quantify mechanical couplings of 2D and 3D lattice structures using nonclassical continuum models and crystallographic symmetry theories. We also explore the design of metamaterials with nonreciprocal constitutive equations. (Keywords: mechanical coupling, micropolar theory, crystallographic theories, symmetry breaking, nonreciprocal behavior)
2. Meta-dynamics: We design metastructures for vibration isolation by integrating kinematic mechanisms with lattice mechanics. By leveraging instability, we create metamaterials with quasi-zero stiffness (QZS) to isolate vibrational motion for multi-modal and selective frequency ranges. (Keywords: vibration isolation, quasi-zero stiffness, mechano-intelligence)
3. Meta-design: We develop active mechanical metamaterials and devices such as mechanical computers and robotic metamaterials. We design lattice geometries using smart materials like shape-memory polymers, shape-memory alloys, piezoelectric materials, magnetic materials, and liquid metals, and manufacture devices using 3D/4D printing techniques. (Keywords: active lattice structures, multi-physics, instability, heat transfer, mechanical computing, robotic metamaterials, physical intelligence)

Applied Research (Mechanical Engineering)

Meta-wheels: Metamaterials can be used to design spokes and shear bands of airless wheels using the theories of elasticity and nonlinear solid mechanics. The principles from meta-statics and meta-dynamics are applied in this endeavor. (Keywords: ring mechanics, visco-hyperelastic elastomer composites, nonreciprocal mechanics, optimization)