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Tube Loop Tensegrities


Tube Loop Tensegrity

Tube Loop Tensegrities

Previously, constructing tensegrities has typically involved making grooves in the end of struts, or drilling holes in the ends of them.

This can generate some problems:

  • The poles extended beyond the end of the cables - resulting an protruding sharp edges which tend to penetrate any covering material;

  • Holes and grooves in metal tubes tend to need deburring if they are not to cause cables to fray.

  • Drilling holes or sawing grooves increases construction costs;

  • Drilling holes or sawing grooves damages the strut material - and generates local weak points;

Here we present a method of constructing tensegrities using struts that are unadulterated tubes, with no need for the cutting of grooves, or drilling of holes.

The methdod is pretty simple - it's illustrated in the diagram above.

Each strut has one or more cables running down its middle.

Each cable passes through two or more struts.

Problems

The model illustatated was constructed using wire and PVC.

The stiffness in the wire makes it difficult to tell how this particular model would behave if everything was perfectly frictionless. However in theory some models without friction will still retain their structural integrity.

In practice a number of measures could be taken to prevent motion of individual cables in the tubes if that proves necessary - including steps such as twisting the cables inside the tubes together, and inserting dowels into the ends of the tubes.

This modelling technique typically results in increased expenditure on cables. You can often avoid having more than two cables running through each strut, though - once you have two cables, others can usually be looped around them or tied to them.


Tim Tyler | Contact | http://hexdome.com/