Optomechanics – Ivory, MSC Patran/Nastran and MS Excel


I wish to correct a misimpression.

I illustrated my last note to you with a graphic of a stabilized inner (elevation) gimbal, with a laser transmitter, laser receiver, IR imager and a gyroscope.  Many of you assumed that was a CAD rendering or a meshed CAD model.  It was neither.  At the time that the FE model was prepared the CAD model could not support that level of detail.  All of that initial structural design on the inner gimbal was done with AEH Ivory in MSC Patran/Nastran supplemented with MS Excel.

Here’s a CAD graphic at the start the structural design on the elevation axis…

…and here’s that Patran graphic of the structural design concept developed from it. This was a design engineering task undertaken at the very start of the project, a trade-off study between pointing stability and on-gimbal mass.  I reduced the pointing error of the imager by 73% (39.6 mr to 10.6 mr) for a weight increase of just 18% (0.96 pounds).  Not a bad day’s work.  And I was able to give the CAD designer a reasonably stable design concept for mounting the imager.  That’s engineering.  The design trade-off study was made possible by the concurrent useof AEH Ivory, MSC Patran/Nastran and MS Excel during the formative early stage. 

Now for the important stuff.  Have you gotten your sun-block and water skis ready yet?

Al H.

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