Optomechanics – Iterate Quickly Early

Colleagues:

Putting EO gear on Navy aircraft is a special sort of challenge, particularly if it’s external stores.  Not only does it have to pass the normal shock and vibration tests, it has to pass the rigors of catapult launches and arrested landings.

AEH was on the team that put active IR countermeasures into NavAir service.  The big challenge was the survival of the IR source which, until that time, existed only in the research lab.  We had to establish its fragility threshold (by testing) and then design its installation to survive the cats-n-traps of carrier service.  The solution turned out to be custom, AEH-designed, shock isolators and snubbers, one of AEH’s applications of the principles of optical flexures.  It was a six-degree-of-freedom “kinematics” problem with about a dozen degrees-of-freedom in the kinetic (design) solution, and non-linear at that.  Great fun!

There aren’t always “canned” tools that the engineer can apply.  This case required writing an interactive numerical integration routine that could be iterated quickly to explore the effects of the numerous design variables.  Spreadsheet approaches were too cumbersome so source-code was written and compiled.  The engineer could quickly modify the design variables and/or computational parameters and rerun the problem.  This enabled a thorough survey of the design space, demonstrations of numerical stability and, ultimately, the determination of the most favorable design configuration.

It’s always good to have a source-code compiler around.  It also helps to keep your other tools sharp.

AEH:  Finding engineered solutions.

Spring must be coming.  The apple trees are in full bloom!

Al H.
2-29-16

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