Knitting Multistability

TL;DR

This paper introduces a novel weft-knitting fabrication method for curved elastic shells that exhibit multistability and snap-through behavior, enabling the design of soft, functional wearable devices with integrated haptic feedback.

Contribution

It presents a new knitting process that induces internal stresses to create multistable, shape-changing textiles for soft wearable electronics, expanding the design space for such devices.

Findings

Knitting induces complex 3D curvatures in textiles.

Identified parameter space for multistability in knitted textiles.

Demonstrated soft conductive switches with haptic feedback.

Abstract

Curved elastic shells can be fabricated through molding or by harnessing residual stresses. These shells often exhibit snap-through behavior and multistability when loaded. We present a unique way of fabricating curved elastic shells that exhibit multistability and snap-through behavior, weft-knitting. The knitting process introduces internal stresses into the textile sheet, which leads to complex 3D curvatures. We explore the relationship between the geometry and the mechanical response, identifying a parameter space where the textiles are multistable. We harness the snapping behavior and shape change through multistability to design soft conductive switches with built-in haptic feedback, and incorporate these textile switches into wearable devices. This work will allow us to harness the nonlinear mechanical behavior of textiles to create functional, soft, and seamless wearable devices. This includes but is not limited to the devices for additional cycling visibility and safety that we envision.