Tensegrity Woven Chair

Mar 2022

Tensegrity woven chair was a challenge of incorporating the lightweight structure prototype of tensegrity into a piece of furniture dedicated to one man. The attempt to integrate principles of digital fabrication involved the progressive material-geometry generation and fine-tuning of joineries.

Ergonomics A typical string chair has parallel strings to fit the butt while maintaining the chair’s shape (a). Other yarn in the back forms a bumpy ruled surface that offers elastic support.

Statics Tensegrity means discontinuous compression. Here the solid wood structure is divided into two frames (b). The strings are in tension, keeping the tensegrity structure in balanced forces (c, d).

Aesthetics The number of holes on each board is tuned so that the string density throughout the chair keeps roughly the same (3cm distance) (e).

Easy Fabrication The wood boards are oriented in a way that the frame joints are kept simple (f). The wood ends are defined by bisecting boxes and are in turn, not flat, making the joints as small as possible while increasing the difficulty in fabrication. Hence ramps are adjusted to be bevel or miter (g). So they are perpendicular to a pair of adjacent faces, making the cutting through the bandsaw possible. The plastic cap joints are relatively small and can be oriented upward when 3D printing to reduce supports needed (h). We use grasshopper to generate drawings for cutting (with top and front views, papers in letter size). Then the wood boards are cut using bandsaws (i).

We minimize the number of strings down to 12 (in weaving order). Each string goes back and forth to balance the forces added while weaving (see below). We use a total length of 30m in our 1/3 scale model.

Product Render / Courtesy of Toraya Kobo by Hiroshi Naito

ARCH 732-005 Principles of Digital Fabrication / University of Pennsylvannia

Co-produced with Yifan Zhao / Instructed by Mikael Avery