RE: [ATM] PLOP and triangles

["lou krajci" <loukrajci@comcast.net>]

>From: Arjan te Marvelde [mailto:arjan.te.marvelde@hetnet.nl]

>How exactly did you model the points that make up a pad? I believe that
>normally PLOP assumes the points, like you use them to model a pad, can
move
>independently.

I set up a PLOP scenario with four points close together (instead of a
single point)...to approximate pads...and tested it at different spacings of
the four points (to simulate large or small pads)...and then tested it with
a single point, which is the 'typical' way we analyze a mirror cell with
PLOP.

>Therefore, following this reasoning you will probably get good results with
>any mirror using only one support and make it as big as the mirror (given
>enough points to model the pad).

In a perfect world, that would be true, if:
- This single large pad perfectly matched the shape of the back of the
mirror
- This single large pad never deformed at all due to forces on it from the
rest of the mirror cell, etc.

>In reality the large pads are more rigid, and may introduce stress.

And that keeps you from cooling the rear surface of the mirror...which can
cause other problems, especially with thicker mirrors.

Tom Krajci
Albuquerque



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