Pre-Torsion Tubular Metamaterials: Multi-Effect Integration for Advanced Functional Applications

Area of Science:

• Materials Science
• Mechanical Engineering
• Nanotechnology

Background:

• Mechanical metamaterials offer properties beyond conventional materials.
• Integrating multiple functionalities into a single metamaterial structure is challenging.
• Existing metamaterials often lack synergistic multi-effect integration.

Purpose of the Study:

• To propose a pre-torsion design paradigm for synergistic coupling of distinct mechanical properties.
• To achieve multi-effect integration (MEI) in auxetic tubular structures (ATSs).
• To demonstrate the practical engineering benefits of this design in applications like fasteners.

Main Methods:

• Numerical simulations and experimental investigations were employed.
• A pre-torsion design paradigm was incorporated into auxetic tubular structures.
• Fabrication and driving-in tests of pre-torsion auxetic nails were conducted.

Main Results:

• The proposed paradigm enabled robust MEI, combining compression-torsion and auxetic effects under axial loading.
• Pre-torsion auxetic nails exhibited easy insertion and damage-free performance.
• Compared to conventional nails, a 52% reduction in energy consumption and a 27.1% decrease in initial peak force were observed during wood penetration.

Conclusions:

• The pre-torsion design paradigm effectively integrates multiple mechanical properties in metamaterials.
• This approach bridges the gap towards practical applications of mechanical metamaterials.
• The design philosophy can be extended to various engineering scenarios for functional structures.