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Alkor Technologies - one of the largest Russian manufacturers of optical windows.
Design windows of optical crystals under pressure.
The anisotropy of mechanical properties of optical crystals leads to the fact that known methods for testing the strength of yield approximate values destructive stresses. Published values of modulus of rupture, apparent limit of elasticity or resistance to bending, as a rule, are averaged over the different crystallographic directions of the test samples. Therefore, when calculating the minimum thickness of the optical window you should always add a certain safety factor.
t min=√(K*P*R2*F/MR),
wherein:
K - a constant minimum safety factor. For unfastened window K = 1.1, for the fastened window K = 0.8.
P - pressure difference
R 2 - radii2 of the window
F - safety factor (from 4 to 6).
MR - Modulus of rupture
The values of the modulus of rupture (MPa) for some crystals are given below:
BaF2 - 26.9, CaF2 - 36.5, Ge - 72.4, LiF - 11.2, MgF2 - 49.6, KBr - 1.1, KCl - 2.3, Sapphire - 448 (minimum), Si - 125.0, NaCl - 2.4, ZnSe - 55.0, ZnS - 59.0.
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