Programming stiff inflatable shells from planar patterned fabrics

TL;DR

This paper presents a single-step fabrication method for creating large, stiff, inflatable shells from patterned fabrics, enabling diverse applications like space structures and emergency shelters by programming their shape and mechanical properties.

Contribution

The authors introduce a novel heat-sealing patterning technique to program shape-changing, stiff inflatable shells from planar fabrics, expanding potential large-scale applications.

Findings

The method enables shape-programmable, stiff inflatable shells.

Structures can resist their own weight at large scales.

Three patterning methods allow precise control of shell geometry.

Abstract

Lack of stiffness often limits thin shape-shifting structures to small scales. The large in-plane transformations required to distort the metrics are indeed commonly achieved by using soft hydrogels or elastomers. We introduce here a versatile single-step method to shapeprogram stiff inflated structures, opening the door for numerous large scale applications, ranging from space deployable structures to emergency shelters. This technique relies on channel patterns obtained by heat-sealing superimposed flat quasi-inextensible fabric sheets. Inflating channels induces an anisotropic in-plane contraction and thus a possible change of Gaussian curvature. Seam lines, which act as a director field for the in-plane deformation, encode the shape of the deployed structure. We present three patterning methods to quantitatively and analytically program shells with non-Euclidean metrics. In addition to shapes, we describe with scaling laws the mechanical properties of the inflated structures. Large deployed structures can resist their weight, substantially broadening the palette of applications.