Re: More Space Elevator news

From: Ian Stirling (root_at_mauve.demon.co.uk)
Date: 06/30/04 

Date: Wed, 30 Jun 2004 13:18:14 GMT

Tony Rusi <marsbeyond@yahoo.com> wrote:
> The real issue is can nanotubes be manufactured defect free in 6000
> yard lengths? And/or can a matrix of sufficient strength be developed.

Ropes of carbon nanotubes, where the individual length is hundreds of
nanometers, and the rope several um long, only glued together by
van-der-valls forces have already obtained 50GPa.

http://www.ruf.rice.edu/~lericson/lericson%20masters%20thesis.pdf

The strength of the matrix does not need to compare to the strength of
the fiber.
It only needs to carry the loads between fibers.
As an example, take two 1m lengths of kevlar fiber (a few um in diameter)
Now, glue them together lengthways with silicone sealant.
Try to pull the fibers through the sealant.
Though the silicone sealant is several orders of magnitude weaker than the
kevlar, the kevlar breaks first.

A 1m kevlar fiber is similar aspect ratio to a few hundred um nanotube.

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