Advancing the Fit, Performance, and Wearing Stability of Wearable Technologies with Active Textiles

Abstract

Advancements in sensors and actuators have propelled wearable technologies toward wide-spread market use, however the physical interface between these technologies and the human body has remained a functional challenge. Passive fabrics are unable to conform around body surface concavities, resulting in reduced garment-body contact. Tunable gar-ment tightness/stiffness is presently attainable only with large-volume pneumatic actuators or manual adjustability mechanisms that increase device complexity and introduce fit in-consistencies. Wearing variability, or the variation in system placement, orientation, and tightness in relation to a body both between use trials and between users, can result in large variation and deterioration in system performance. This work investigates pervasive wear-able device challenges and proposes novel methods of exploiting active (shape changing) materials within wearable systems to accomplish enhanced fit, performance, and wearing stability of wearable devices. Fit, or the garment-body dimensional relationship, is investigated through the design of circumferentially contractile and thermally-responsive self-fitting garments. These self-fitting garments are composed of active textiles that accomplish enhanced garment-body contact by topographically conforming around complex body surface in response to body heat. Fit is further enhanced through the introduction of active auxetic behaviors, which enable active textiles to dynamically contract in two directions of a 2D structure (up to 30%in one direction and 40% in the other) for dynamic garment length and width adjustment. Performance, or the physical garment-body interaction that produces tightness/compression or locally-applied force, is investigated through the design of active textile-based medical compression devices that accomplish generated blocked forces up to 308 N/m for on-body compressive pressure over 55 mmHg. Lastly, wearing stability (in terms of consistent garment tightness across a user group) is demonstrated through design strategies and pattern making procedures, introducing methods to preserve garment performance across a user population. By exploiting the capabilities of active materials within the mechanics of fil-aments, yarns, textiles, and systems, this work presents key advancements for wearable device fit, performance, and wearing stability.