Double-network-inspired mechanical metamaterials

Area of Science:

• Materials Science
• Mechanical Engineering
• Polymer Science

Background:

• Mechanical metamaterials often face a trade-off between high stiffness/strength and low ductility/stretchability.
• Double-network hydrogels offer a unique combination of high stiffness and stretchability, leading to exceptional toughness.

Purpose of the Study:

• To develop double-network-inspired metamaterials that integrate stiff and compliant components.
• To achieve unprecedented combinations of stiffness and stretchability in metamaterials.
• To explore enhanced energy dissipation mechanisms in these novel materials.

Main Methods:

• Integration of monolithic truss (stiff) and woven (compliant) components into a metamaterial architecture.
• Nonlinear computational mechanics modeling to elucidate energy dissipation mechanisms.
• Introduction of internal defects to study their effect on mechanical properties and energy dissipation.

Main Results:

• Achieved a tenfold increase in stiffness and stretchability compared to pure monolithic or woven counterparts.
• Computational models revealed enhanced energy dissipation due to frictional dissipation from interpenetrating networks.
• Demonstrated a threefold increase in energy dissipation by introducing defects, attributed to failure delocalization.

Conclusions:

• The developed double-network-inspired metamaterials successfully overcome the stiffness-ductility trade-off.
• Interpenetrating network design enhances energy dissipation through friction and failure delocalization.
• This approach opens new possibilities for designing high-compliance metamaterials inspired by polymer network topologies.