Tensegrity Concept Models

When developing CAD models I often consider how I would go about actually building a physical representation of the design I see before me on screen.

I wanted to use readily available material in such a manner as to provide good compression resistance for the struts and minimum expansion (stretch) for the tendons.

Naturally I spent some time browsing the Internet to see what others were doing in the construction of their models. The majority of models comprised a simple sturdy strut connected to the tendons by either a screw at the end or tied. The tendons in most cases were either string or fishing line.

I quite liked the idea of using fishing line for the tendons and decided that utilising crimps would be ideal to form a connection to the end of the struts.
For the struts I decided on a composite material approach as shown in the following images.



The image on the left is a composite construction comprising thin dowel restrained along its length by beads. The dowel on its own is ineffective as a compression member but when constrained by a series of close fitting beads this becomes an effective solution. This could be further improved by using hollow spacers, either aluminium or steel with flat ends thus increasing the contact surface area. The dowel in this case keeps the "beads" together and forms a projection at the end of the strut to which we can simply hook on the tendons as shown in the left or simply act as a shaft to constrain washers to which we in turn fit the tendons (right image).

The image on the right is similarly a composite construction but this time the dowel is fitted with a close fitting sheath of plastic pipe. Again an effective solution with the ends of the pipe forming an edge to prevent the washers slipping down the strut.

Composite construction techniques provide a good alternative to the traditional approach of building tensegrity models. The idea that the selected materials provide restraint to the compression strut as well as acting as a contact surface for attaching the tendons without the need to use screws works very well.

Recently my work was featured in the Tensegity Wiki.
Tensegrity Wiki link: http://tensegritywiki.blogspot.com
If you would like more technical information or have a general enquiry please drop me a line at hught2008@gmail.com