Entanglement-driven responses through multiscale 3D-printed knits

Area of Science:

• Materials Science
• Mechanics of Materials
• Textile Engineering
• Additive Manufacturing

Background:

• Textiles derive toughness from topology, not just material properties.
• Existing architected materials seldom leverage interlooping and sliding contacts for advanced behavior.
• A quantitative framework linking stitch structure to mechanical behavior is lacking.

Purpose of the Study:

• To reinterpret knitting as a general strategy for designing 3D entangled solids with programmable mechanics.
• To develop a predictive quantitative framework for stitch structure and mechanical behavior.
• To explore the potential of multimaterial 3D printing for creating novel knitted materials.

Main Methods:

• Utilized a geometrically exact description of each stitch.
• Employed multimaterial 3D printing, a topology-agnostic fabrication approach.
• Created planar and volumetric knits with controlled loop parameters.

Main Results:

• 3D-printed knits exhibit programmable stiffness, strength, and energy dissipation controlled by loop parameters.
• Printed fabrics accurately replicate the nonlinear, anisotropic, and hysteretic responses of conventional textiles.
• A normalization method unifies the stress-strain behavior of diverse knits on a master curve.
• Volumetric knits show tunable stiffness and dissipation via prestrain.
• Fabricated knitted structures across scales, down to the micrometer level.

Conclusions:

• Knitting serves as a versatile strategy for designing 3D entangled solids with tunable mechanical properties.
• Multimaterial 3D printing enables precise control over the mechanics of knitted architectures.
• Entangled filaments, through their topology, form a basis for new material architectures with encoded mechanics.