Table 1 Main mechanical categories of mechanical metamaterials and their typical mechanical characteristics
Formation | |||
---|---|---|---|
Material level | Material | ||
Metallic | Polymeric | ||
Mechanism | Constitutive relationship | • Work hardening constitutive relationship (e.g., Johnson-Cook model and Zerilli-Armstrong model) • Dynamic recovery constitutive relationship (e.g., Arrhenius model) • Dynamic recrystallization constitutive relationship (e.g., Sellars model) • Unified constitutive relationship (e.g., Miller model and Walker model) | • Thermoviscoelasticity-based models • Phase evolution-based models |
Structural level | Overall | ||
2D beam or plate | 3D cube and others | ||
Origami or kirigami | • Origami metamaterials with square twist76 • Reconfigurable origami metamaterials81 | • 3D transformable origami metamaterials with multiple degrees of freedom79 • Reentrant origami metamaterials71 • Programmable self-locking origami metamaterials78 | |
Unit | Chiral | • 3D chiral metamaterials with a twist48 • Self-rotating 3D chiral mechanical metamaterials83 • 3D chiral metamaterials with topological design66 • 3D chiral metamaterials with modular design57 | |
Lattice | • Hierarchical lattice materials86 • Functionally graded cellular composites with auxetics150 • Cellular flexible metamaterials172 | • Alternating pentamode lattices87,174 • 3D plate-lattices54 • Reversibly assembled cellular composite materials88 • 3D cellular metamaterials with anti-chiral topology91 |
Performance | |||
---|---|---|---|
Mechanical characteristics | Current status | ||
Advantages | Limitations | ||
Response | Ultra-stiffness | • Energy absorption • Vibration reduction | • Difficulties in design, characterization and application175 • Difficulties in fabrication (e.g., ultra-fine complex nanostructures, multi-material systems and super-large structures)176 |
Ultra-lightweight | • Sound insulation, absorption and reduction54,104 • Low consumables and cost | ||
Negative response | • Negative Poisson’s ratio (e.g., shear, impact and damage resistance, and energy absorption)45,69,71,177 • Negative Stiffness (e.g., large bearing capacity and small deformation, and low natural frequency)73 • Negative thermal expansion (e.g., high thermal and electrical conductivity)178,179 | ||
Programmable response | • Controllability • Tunable stimuli |