Vacuum and window with rim and center support
Abstract
Expressions for the bending stresses of a telescope window with a small additionally supported central area are presented. Expressions for maximum bending elongation are taken from the literature, and those for radial and tangential stresses are deduced from the bending moments for given distances from the plate center. Analysis shows that where the central bending excursion is zero, very high stresses equal to those in a window which is not centrally supported occur at the central support. Overall stress can be reduced by choosing the support pressure inside the central area so that radial stress vanishes at the outer boundary of the central support. Along the rim, a hydraulic support system consisting of two concentric O-shaped rings is suggested. For the central support, a frictionless hydraulic piston and an O-ring sealed support plate are advocated.
- Publication:
-
Large European Solar Telescope
- Pub Date:
- April 1982
- Bibcode:
- 1982lest.rept..205M
- Keywords:
-
- Reflecting Telescopes;
- Solar Instruments;
- Windows (Apertures);
- Bending Moments;
- Flexing;
- Hydraulics;
- Poisson Ratio;
- Supports;
- Thin Plates;
- Astronomy