LIGO Document T1000542-v4

Stress analysis of the monolithic flexures for the Arm Cavity Baffle (ACB), ITM Elliptical Baffle and the Cryo-pump/Manifold Baffle

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T - Technical notes
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15 Sep 2010, 11:55
Extensional and bending stresses for these three AOS flexure designs are calculated by handbook formulas. A comparison to an FEA for a couple of cases confirms the handbook formula accuracy to within a few per cent.

Note that torsional stresses have yet to be calculated.

The effect of the flexure's elastic restoring force on the pendulum frequency was calculated using ANSYS11 Workbench (dynamic analysis with gravitational acceleration).

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Notes and Changes:
calculated flexure extensional and bending stresses for:
a) Arm Cavity Baffle
b) ITM Elliptical Baffle
c) Manifold Cryopump Baffle

1) The Arm Cavity Baffle flexure was not adequate in 316SS (D1200781-v1), but is OK in Maraging c250 (D1200781-v2)
2) The ITM Elliptical Baffle flexure (D1002340-v3) must be changed from 316SS to:
a) Maraging c250, or
b) tempered 400 series SS, or
c) changed to D1200781-v2
3) The Manifold Cryopump Baffle flexure (D1001970-v3) is not adequate in 302SS, 304SS or 316SS. It must be changed to:
a) Maraging c250, or
b) tempered 400 series SS

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