Markus Becker wrote:

> Tor Olav Kristensen wrote:
> >
> > Strange. If so, I wonder how it is applied.
>
> You project a stripe pattern onto an object. You take
> a CCD-Image of this pattern. Then you "stress" the object
> (put pressure in/onto it or whatever), project the same
> pattern on it and take another picture. You overlay
> those picture and you get a moiree pattern that you can
> analyse.

So from the co-ordinates where the two sets of stripes cross,
one can deduct information about how the material has
moved/deformed in that region ?

This leads me to think about the nice coloured patterns
that appear when one shines polarized light through stressed
acrylic materials and then views this through a polarized filter.

I did a search for photoelasticy and got this hit:
http://www.britannica.com/bcom/eb/article/1/0,5716,61311+1,00.html

(I did not know that Britannica now is available on the net. :)


And of coarse then I had to look up Moire in Brittanica,
and then I found this:
http://www.britannica.com/bcom/eb/article/5/0,5716,54535+1+53206,00.html

(Here they also mention other useful applications for the Moire
patterns.)


Tor Olav
--
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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