[ATM] PLOP and the mirror support.

["Jerry Reddell" <jerry.p.reddell63@sbcglobal.net>]

First let me say that I think the graphical version PLOP is a great tool and
program. Everyone should use it. 

I have been playing with it to determine how best to modify a commercial 10
inch mirror cell (all cast aluminum) to improve its support.. While
experimenting with different support rings, number of supports, and radius
of support rings I found several surprises. The most notable being the
dramatic negative affect on the error by adding supports in the area where
the most droop ( i want to say sag) occurs for a near ideal support. The
intuitive thought is that the added support would further reduce the error,
but instead the error increase by a factor of 10 or more.....

The analysis obviously uses 'point' support for calculations. The size of
these PLOP support points is very small compared to the size of the actual
built support area...Since the as build support area is in affect many PLOP
support points arranged in a group, and considering the above mentioned
unexpected increase in error by adding support points in obvious locations,
the question comes to mind that the as built cell and supports may adversely
perform quite differently by increasing the error above what one expects
using PLOP...

Does anyone know of a way to get PLOP to simulate the actual as built
support area?  

Also when one builds a floatation type cell, is the mirror siliconed to each
of  the support points or is the mirror allowed to 'slip and slide' a bit
with the restraints being elsewhere.? 

Jerry Reddell


_______________________________________________
ATM mailing list http://www.atmlist.net/