Twist-Controlled Force Amplification and Spinning Tension Transition in Yarn

Area of Science:

• Materials Science
• Textile Engineering
• Physics of Soft Matter

Background:

• Yarn spinning transforms loose fibers into cohesive structures.
• Understanding the transition from fiber assembly to yarn formation is crucial for textile manufacturing.
• Existing models may not fully capture the complex mechanics of fiber interactions during spinning.

Purpose of the Study:

• To investigate the spinning transition of cohesionless fibers into yarns.
• To elucidate the role of frictional forces and mechanical-statistical modeling in yarn formation.
• To identify the key parameters controlling the yarn spinning process.

Main Methods:

• Combined experimental data with numerical simulations.
• Developed a mechanical-statistical model for twisted yarns.
• Analyzed the scaling of frictional forces with twist angle (θ).
• Introduced and analyzed a dimensionless number (H) governing the transition.

Main Results:

• The spinning transition is continuous yet sharp, characterized by an exponential amplification of frictional forces (expθ²).
• The transition is governed by a single dimensionless number (H) incorporating twist, friction, and geometry.
• A critical value (H_c ≈ 30) signifies fiber locking at tensile strength, imposing constraints on yarn slenderness and pitch.
• An optimal yarn radius is predicted based on this critical value.

Conclusions:

• The study provides a unified theoretical framework for yarn spinning.
• The findings explain the necessity of slender yarn structures and predict optimal radii.
• The model's predictions are validated by experimental results using cotton fibers.