Mechanics-informed fabric actuators with aligned fiber crossings

Area of Science:

• Textile engineering
• Materials science
• Mechanical engineering

Background:

• Engineering unobtrusive mechanical assistance into clothing requires energy-dense, compliant actuators with thin profiles.
• Existing shape memory alloy (SMA) actuators face limitations in performance and form factor.

Purpose of the Study:

• To develop novel textile actuators with enhanced performance for mechanical assistance in daily-life clothing.
• To investigate the mechanics and optimize the design of SMA-based textile actuators.

Main Methods:

• Interlacing shape memory alloy (SMA) fibers in a periodic X-Crossing geometry.
• Developing a variable-stiffness mechanics model to predict stress-strain behavior and force-contraction relations.
• Characterizing actuator performance in terms of passive stretching, thermal contraction, and load-lifting capacity.

Main Results:

• The X-Crossing actuator design demonstrated superior performance, achieving 50% contraction and lifting 1 kg with a 4.5-gram actuator.
• Actuators could be passively stretched to 160% and achieved a maximum measured contraction strain of 55%.
• The developed mechanics model accurately predicted actuator behavior and informed design optimization.

Conclusions:

• The X-Crossing SMA textile actuators represent a significant advancement for wearable mechanical assistance.
• The developed mechanics model provides a theoretical framework for designing and scaling SMA fabric actuators.
• Demonstrated applications in weight lifting and on-body compression highlight the potential of these actuators for practical use.